Highly sensitive and selective “off-on” fluorescent sensing platform for ClO − in water based on silicon quantum dots coupled with nanosilver Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-14 Lirong Liu, Gangbing Zhu, Wei Zeng, Baohe Lv, Yinhui Yi
We present a new “off-on” fluorescence probe for detecting hypochlorite (ClO−) based on silicon quantum dots coupled with silver nanoparticles (SiQDs/AgNPs) as nanocomplexes. Via introducing N-[3-(trimethoxysilyl)propyl]ethylenediamine and catechol as initial reactants, silicon quantum dots (SiQDs) with excellent properties were synthesized through a simple hydrothermal method. Transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the morphology and structure of quantum dots. The fluorescence of SiQDs could be quenched by the silver nanoparticles (AgNPs) by surface plasmon-enhanced energy transfer (SPEET) from SiQDs (donor) to AgNPs (acceptor). The AgNPs could be etched by adding ClO−, thus freeing the SiQDs from the AgNP surfaces and restoring the SiQDs’ fluorescence. The sensing system exhibits many advantages, such as wide linear response range, high sensitivity, and excellent selectivity. Under optimized conditions, wide linear ranges (from 0.1 to 100.0 μM) and low detection limits (0.08 μM) were obtained for ClO−.
Recent trends in analysis of nanoparticles in biological matrices Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-14 Zuzana Gajdosechova, Zoltan Mester
The need to assess the human and environmental risks of nanoparticles (NPs) has prompted an adaptation of existing techniques and the development of new ones. Nanoparticle analysis poses a great challenge as the analytical information has to consider both physical (e.g. size and shape) and chemical (e.g. elemental composition) state of the analyte. Furthermore, one has to contemplate the transformation of NPs during the sample preparation and provide sufficient information about the new species derived from such alteration. Traditional techniques commonly used for NP analysis such as microscopy and light scattering are still frequently used for NPs in simple matrices; however, they have limitations in the analysis of complex environmental and biological samples. On the other hand, recent improvements in data acquisition frequencies and reduction of settling time of ICP-MS brought inorganic mass spectrometry into the forefront of NPs analysis. However, with the increasing demand of analytical information related to NPs, emerging techniques such as enhanced darkfield hyperspectral imaging, nano-SIMS and mass cytometry are in their way to fill the gaps. This trend review presents and discusses the state-of-the-art analytical techniques and sample preparation methods for NP analysis in biological matrices.
Size-dependent sub-proteome analysis of urinary exosomes Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-14 Sheng Guan, Hailong Yu, Guoquan Yan, Mingxia Gao, Weibing Sun, Xiangmin Zhang
Exosomes are cell-derived functional microparticles which exist in most body fluids. They carry abundant signaling molecules to transfer information between cells and microenvironment. Research on exosomes’ heterogeneity and constitute variations has been a heated topic in recent years. In this work, size-dependent sub-proteome analysis of urinary exosomes was investigated by size exclusion chromatography (SEC) firstly. The particle size of urinary exosomes is distributed in four main ranges naturally. We found out that these fractions contained sub-proteomes with great difference in constitution. In each fraction, 206, 134, 157, and 276 unique proteins were identified by LC-MS/MS. Differential expression of exosomal markers such as TSG101, CD9, CD63, and caveolin-1 was observed in these fractions by western blots. Biological function annotation indicated that the proteins identified in each fraction were involved in different molecular and cellular processes. It is proven that SEC can serve as an efficient analytical tool for exosomes isolation and fractionation. This work provides a new strategy to classify exosomes into sub-populations for comprehensive study of heterogeneous functionalities.
Classifying single fibers based on fluorinated surface treatments Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-14 Michael J. Dolan, Robert D. Blackledge, Kaveh Jorabchi
Fibers are an important form of forensic evidence, but their evidential value can be severely limited when the identified characteristics of the fibers are common, such as blue cotton. Detecting chemical fiber treatments offers an avenue to further classify fibers and to improve their evidential value. In this report, we investigate the potential of fluoropolymer fiber coatings, used to impart oil and water-repellent properties in fabrics, for differentiating between fibers. The thin nature of these fiber surface modifications creates an analytical challenge for their detection on a single fiber, a typical sample size for forensic evidence. Specifically, pyrolysis-gas chromatography-mass spectrometry (py-GC-MS) has shown promising selectivity but the sensitivity of the method is not adequate for single-fiber analysis of fluorinated coatings. To overcome this challenge, we utilize a newly developed elemental ionization source, plasma-assisted reaction chemical ionization (PARCI). The high sensitivity of py-GC-PARCI-MS for elemental fluorine analysis offers selective and sensitive detection of fluorinated pyrolysates among the non-fluorinated pyrolysates of the fiber core. As a result, fluoropolymer coatings are detected from 10-mm single-fiber samples. The technique is applied for classification of 22 fiber types, resulting in 4 distinct groups via hierarchical cluster analysis based on similarity of fluorine pyrograms. These results present the first study to classify fibers based on fluorinated coatings, and highlight the potential of py-GC-PARCI-MS for forensic analyses.
A hierarchical cobalt/carbon nanotube hybrid nanocomplex-based ratiometric fluorescent nanosensor for ultrasensitive detection of hydrogen peroxide and glucose in human serum Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-13 Pengcheng Qian, Yingnan Qin, Yanlong Lyu, Yunfei Li, Lei Wang, Shuo Wang, Yaqing Liu
Highly sensitive detection of H2O2 and glucose is critical for fundamental research and disease diagnosis. A ratiometric sensor can simultaneously afford two readout signals that provide an internally normalized response to change, thereby reducing false results and improving detection accuracy. A novel ratiometric fluorescent nanosensor for ultrasensitive detection of hydrogen peroxide and glucose was constructed on the basis of the peroxidase-like properties of a hierarchical cobalt/carbon nanotube hybrid nanocomplex (Co-CNT). The as-prepared Co-CNT catalyzes the transformation of the non-fluorescent Amplex Red (AR) into a fluorescent derivative and the transformation of fluorescent scopoletin (SC) into a non-fluorescent derivative in the presence of H2O2. The sensing system changes colour from yellow to blue, which can be clearly seen with the naked eye. With the fluorescence ratio of AR to SC as readout, the detection limit of H2O2 reaches as low as 100 nM. The developed assay is further utilized for determining H2O2-related oxidase reactions with the glucose and glucose oxidase system as model. Glucose can be selectively and sensitively detected as low as 150 nM. Satisfactory recoveries are obtained for glucose detection in serum samples. The developed assay is simple in terms of preparation and operation and provides a straightforward method for cost-effective and reliable detection of H2O2 and H2O2-related reactions in clinical diagnosis and biomedical applications.
Liposome protein corona characterization as a new approach in nanomedicine Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-13 Anna Laura Capriotti, Chiara Cavaliere, Susy Piovesana
This trends article describes the analytical approaches for the in-depth characterization of the protein corona on liposome nanoparticles. In particular, examples since 2014 are summarized according to the analytical approach. Traditional protein corona characterizations from in vitro static experiments are provided along with the newly introduced experimental setups for characterization of the protein corona by in vitro dynamic and in vivo studies. Additionally, a special attention is also devoted to the need for introduction of new experimental workflows for characterization of a much wider array of biomolecules. In the most recent years, an extension of the protein corona concept to the biomolecular corona was introduced, and the analytical targets are no longer restricted to proteins, but to other important biomolecules as well, as they can potentially affect the biodistribution and interaction of nanoparticles with the biological systems. The few recent examples in this field are discussed for the characterization of metabolites and lipids in the biomolecular corona with examples, also extending the discussion from liposome to other types of nanoparticles. A final discussion is provided on the potential key role of the most recent omics approaches in the study of the nano-bio interface, with an overview on top-down proteomics, which allows a better elucidation of proteoforms, and on lipidomics and metabolomics, which allow a comprehensive untargeted characterization of lipids and metabolites, respectively.
Fluorescent kinetics combined with fourth-order calibration for the determination of diclofenac sodium in environmental water Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-13 Jiao Li, Jie Xu, Wenying Jin, Zhongsheng Yi, Chenbo Cai, Xuefen Huang, Jinfang Nie, Yun Zhang
A method that combines five-way fluorescence kinetics with fourth-order calibration for interference-free quantification of diclofenac sodium in river water was proposed and tested. Traditional fluorescence methods may not be suitable for such measurements since the fluorescence properties of the analyte are highly dependent on both pH and irradiation time in situ. In the method considered here, a five-way emission-excitation-time-pH data array was obtained from the samples by introducing the pH level and irradiation time as two extra modes. Then the data array was resolved by three fourth-order calibration algorithms: alternating fitting weighted residue quinquelinear decomposition (AFWRQQLD), five-way parallel factor analysis (five-PARAFAC), and alternating quinquelinear decomposition (AQQLD). The average recoveries and detection limits calculated for diclofenac sodium in a set of analyte-spiked river water samples using AFWRQQLD, five-PARAFAC, and AQQLD were 97.2 ± 3.2% and 1.9 ng mL−1, 96.8 ± 3.0% and 4.0 ng mL−1, and 92.6 ± 2.7% and 2.5 ng mL−1, respectively. A study of other figures of merit, statistical analysis, an elliptical joint confidence region test, and a t-test were additionally carried out to validate the analytical performance of the proposed method in detail. The results demonstrated that this new method required only two steps (fluorescence measurement and algorithm analysis) to determine the analyte concentration. It could therefore provide the basis for developing novel reliable and sensitive approaches for the accurate detection of pharmaceutical pollutants with unstable fluorescence properties in real complex matrices such as environmental water samples.
The role of incurred materials in method development and validation to account for food processing effects in food allergen analysis Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-13 Monica Mattarozzi, Maria Careri
The issue of undeclared allergens represents a matter of great concern, being the subject of many alert notifications by the Rapid Alert System for Food and Feed portal of the European Commission, often leading to food recalls. The availability of reliable analytical approaches able to detect and quantify hidden allergens in processed foods is increasingly requested by the food industry, food safety authorities and regulatory bodies to protect sensitive consumers’ health. The present review discusses the fundamental role of incurred materials for method development and analytical performance assessment in a metrology perspective on testing for undeclared allergens in processed foodstuffs. Due to the nature of the analytes and their susceptibility to various processing effects, reliability and comparability of results have posed a great challenge. In this context, the use of incurred samples as reference materials permits simulation of the effects of food processing on target analyte structure affecting analyte extractability and detectability.
Enhanced electrochemiluminescent brightness and stability of porphyrins by supramolecular pinning and pinching for sensitive zinc detection Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-12 Chenyu Zheng, Yufeng Sheng, Yong Liu, Ying Wan, Guang Liu, Xutong Zhang, Meng Yang, Kai Kang, Jingping Liu, Kefeng Ma, Shengyuan Deng
Ultrasensitive electrochemiluminescence (ECL) detection can benefit substantially from the rational configuration of emitter−enhancer stereochemistry. Here, using zinc(II) meso-5,10,15,20-tetra(4-sulfonatophenyl)porphyrin (ZnTSPP) as a model, we demonstrate that both the ECL intensity and the photostability of this emitter were significantly improved when it was trapped in pyridyl-bridged β-cyclodextrin dimer (Py(CD)2); a synthetic enhancer that is ECL inactive. Through NMR characterization, we confirmed that ZnTSPP formed a clam-like inclusion complex involving pinning and pinching forces from the biocompatible container Py(CD)2. Up to a threefold increase in the ECL brightness of ZnTSPP was witnessed when it was encapsulated in β-CD. Absorption and emission spectroscopic data revealed that both the extended excitation lifetime and the restricted mobility of the guest contributed to the observed improvement in signal transduction within the host molecule. This bioinspired entrapment also led to a marked boost in ECL stability. With the aid of the newly identified coreactant H2O2, the hollow TSPP@Py(CD)2 system was employed to create a Zn2+-selective probe that was capable of sensitive and accurate zinc detection. The observed increase in ECL conversion and enhanced photophysical properties of this compact supramolecular assembly render it a novel template for enhancing ECL in analytical applications.
Metabolomic and lipidomic characterization of Oxalobacter formigenes strains HC1 and OxWR by UHPLC-HRMS Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-11 Casey A. Chamberlain, Marguerite Hatch, Timothy J. Garrett
Diseases of oxalate, such as nephrolithiasis and primary hyperoxaluria, affect a significant portion of the US population and have limited treatment options. Oxalobacter formigenes, an obligate oxalotrophic bacterium in the mammalian intestine, has generated great interest as a potential probiotic or therapeutic treatment for oxalate-related conditions due to its ability to degrade both exogenous (dietary) and endogenous (metabolic) oxalate, lowering the risk of hyperoxaluria/hyperoxalemia. Although all oxalotrophs degrade dietary oxalate, Oxalobacter formigenes is the only species shown to initiate intestinal oxalate secretion to draw upon endogenous, circulating oxalate for consumption. Evidence suggests that Oxalobacter regulates oxalate transport proteins in the intestinal epithelium using an unidentified secreted bioactive compound, but the mechanism of this function remains elusive. It is essential to gain an understanding of the biochemical relationship between Oxalobacter and the host intestinal epithelium for this microbe to progress as a potential remedy for oxalate diseases. This investigation includes the first profiling of the metabolome and lipidome of Oxalobacter formigenes, specifically the human strain HC1 and rat strain OxWR, the only two strains shown thus far to initiate net intestinal oxalate secretion across native gut epithelia. This study was performed using untargeted and targeted metabolomics and lipidomics methodologies utilizing ultra-high-performance liquid chromatography-mass spectrometry. We report our findings that the metabolic profiles of these strains, although largely conserved, show significant differences in their expression of many compounds. Several strain-specific features were also detected. Discussed are trends in the whole metabolic profile as well as in individual features, both identified and unidentified.
Succinylated Jeffamine ED-2003 coated polycarbonate chips for low-cost analytical microarrays Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-11 Jonas Bemetz, Catharina Kober, Verena K. Meyer, Reinhard Niessner, Michael Seidel
Analytical microarrays feature great capabilities for simultaneous detection and quantification of multiple analytes in a single measurement. In this work, we present a rapid and simple method for bulk preparation of microarrays on polycarbonate sheets. Succinylated Jeffamine® ED-2003 was screen printed on polycarbonate sheets to create a polyfunctional shielding layer by baking at 100 °C. After microdispension of capture probes (antibodies, oligonucleotides, or small molecules) in a microarray format, chips were assembled with a flow cell from double-sided tape. It was shown that the shielding layer was firmly coated and suppressed unspecific binding of proteins. Universal applicability was demonstrated by transferring established flow-based chemiluminescence microarray measurement principles from glass slides to polycarbonate chips without loss of analytical performance. Higher chemiluminescence signals could be generated by performing heterogeneous asymmetric recombinase polymerase amplification on polycarbonate chips. Similar results could be shown for sandwich microarray immunoassays. Beyond that, lower inter- and intra-assay variances could be measured for the analysis of Legionella pneumophila Serogroup 1, strain Bellingham-1. Even surface regeneration of indirect competitive immunoassays was possible, achieving a limit of detection of 0.35 ng L−1 for enrofloxacin with polycarbonate microarray chips. Succinylated Jeffamine ED-2003 coated polycarbonate chips have great potential to replace microtiter plates by flow-based chemiluminescence microarrays for rapid analysis. Therefore, it helps analytical microarrays to advance into routine analysis and diagnostics.
Correction to: Analysis of glipizide binding to normal and glycated human serum albumin by high-performance affinity chromatography Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-09 Ryan Matsuda, Zhao Li, Xiwei Zheng, David S. Hage
The authors would like to call the reader’s attention to the following corrections in this article. In the description given for the process of preparing glycated human serum albumin under “In vitro glycation of HSA”, the concentrations of D-glucose that were employed were 15 mM and 30 mM.
Simultaneous detection of fumonisin B 1 and ochratoxin A using dual-color, time-resolved luminescent nanoparticles (NaYF 4 : Ce, Tb and NH 2 -Eu/DPA@SiO 2 ) as labels Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-09 Sobia Niazi, Imran Mahmood Khan, Lv Yan, Muhammad Issa Khan, Ali Mohsin, Nuo Duan, Shijia Wu, Zhouping Wang
A rapid and highly sensitive time-resolved fluorescence (TRF)-based aptasensor for simultaneous recognition of mycotoxins ochratoxin A (OTA) and fumonisin B1 (FB1) was developed using multi-color, Ln3+-doped time-resolved fluorescence nanoparticles (TRF-NPs) (NaYF4: Ce, Tb and NH2-Eu/DPA@SiO2 NPs) coupled with complementary strand DNA (cDNA) as luminescence probe and aptamers-conjugated amine-functionalized Fe3O4 magnetic nanoparticles (MNPs) act as a capture probe. Under the optimized conditions, the time-resolved fluorescence intensities at 544 and 618 nm corresponded with Tb3+ and Eu3+, respectively, were used to measure FB1 (Y = 19,177.1 + (− 12,054.4)x, R2 = 0.9917) and OTA (Y = 4138.8 + (− 11,182.6)x, R2 = 0.9924), respectively. The limits of detection (LODs) for FB1 and OTA were 0.019 pg mL−1 and 0.015 pg mL−1, respectively, which were much lower than previously described methods for simultaneous recognition of mycotoxins OTA and FB1 while detection range varied from 0.0001–0.5 ng mL−1. This aptasensor was effectively applied to quantity FB1 and OTA in maize samples and results were compared with ELISA method. This is the first reported time-resolved fluorescence (TRF)-based aptasensor to detect two agriculturally important toxins in the maize. The developed aptasensor has potential to be used for detection of toxins in food safety fields.
Graphene-modified electrodes for sensing doxorubicin hydrochloride in human plasma Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-09 Fereshteh Chekin, Vladyslav Myshin, Ran Ye, Sorin Melinte, Santosh K. Singh, Sreekumar Kurungot, Rabah Boukherroub, Sabine Szunerits
Doxorubicin (DOX), an anthracycline molecule, is currently one of the most widely used anticancer drugs in clinics. Systematic treatment of patients with DOX is known to be accompanied by several unpleasant side effects due to the toxicity of the drug. Thus, monitoring of DOX concentration in serum samples has become increasingly important to avoid side effects and ensure therapeutic efficiency. In this study, we discuss the construction of a disposable electrochemical sensor for the direct monitoring of DOX in clinical blood samples. The sensor is based on coating a gold electrode in a flexible integrated electrode construct formed on polyimide sheets using photolithography, with nitrogen-doped reduced graphene oxide (N-rGO) suspended in chitosan. Under optimized conditions, a linear relationship between the oxidative peak current and the concentration of DOX in the range of 0.010–15 μM with a detection limit of 10 nM could be achieved. The sensor was adapted to monitor DOX in serum samples of patients under anticancer treatment.
Quantitative characterization of glutaminolysis in human plasma using liquid chromatography-tandem mass spectrometry Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-09 Yunfei Hua, Xuping Yang, Ruiting Li, Peifang Liu, Peijia Liu, Linrui Li, Xia Yuan, Xiaoyi Hua, Yuan Tian, Zunjian Zhang, Yin Huang
Glutaminolysis is the metabolic pathway that lyses glutamine to glutamate, alanine, citrate, aspartate, and so on. As partially recruiting reaction steps from the tricarboxylic acid (TCA) cycle and the malate-aspartate shuttle, glutaminolysis takes essential place in physiological and pathological situations. We herein developed a sensitive, rapid, and reproducible liquid chromatography-tandem mass spectrometry method to determine the perturbation of glutaminolysis in human plasma by quantifying 13 involved metabolites in a single 20-min run. A pHILIC column with a gradient elution system consisting of acetonitrile-5 mM ammonium acetate was used for separation, while an electrospray ionization source (ESI) operated in negative mode with multiple reaction monitoring was employed for detection. The method was fully validated according to FDA’s guidelines, and it generally provided good results in terms of linearity (the correlation coefficient no less than 0.9911 within the range of 0.05–800 μg/mL), intra- and inter-day precision (less than 18.38%) and accuracy (relative standard deviation between 89.24 and 113.4%), with lower limits of quantification between 0.05 and 10 μg/mL. The new analytical approach was successfully applied to analyze the plasma samples from 38 healthy volunteers and 34 patients with type 2 diabetes (T2D). Based on the great sensitivity and comprehensive capacity, the targeted analysis revealed the imperceptible abnormalities in the concentrations of key intermediates, such as iso-citrate and cis-aconitate, thus allowing us to obtain a thorough understanding of glutaminolysis disorder during T2D.
Label-free evaluation of small-molecule–protein interaction using magnetic capture and electrochemical detection Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-09 Carolina V. Uliana, Tássia R. de Oliveira, Márcia R. Cominetti, Ronaldo C. Faria
The evaluation of interaction between small molecules and protein is an important step in the discovery of new drugs and to study complex biological systems. In this work, an alternative method was presented to evaluate small-molecule–protein interaction by using ligand capture by protein-coated magnetic particles (MPs) and disposable electrochemical cells. The interaction study was conducted using -gingerol from ginger rhizome and a transmembrane protein αVβ3 integrin. Initially, the electrochemical behavior of the natural compound -gingerol was evaluated with the disposable carbon-based electrodes and presented an irreversible oxidation process controlled by diffusion. The analytical curve for -gingerol was obtained in the range of 1.0 to 20.0 μmol L−1, with limit of detection of 0.26 μmol L−1. Then MPs coated with αVβ3 integrin were incubated with standard solutions and extracts of ginger rhizome for -gingerol capture and separation. The bioconjugate obtained was dropped to the disposable electrochemical cells, keeping a permanent magnet behind the working electrode, and the binding process was evaluated by the electrochemical detection of -gingerol. The assay method proposed was also employed to calculate the -gingerol–αVβ3 integrin association constant, which was calculated as 4.3 × 107 M−1. The method proposed proved to be a good label-free alternative to ligand–protein interaction studies.
Programmable RNA-based systems for sensing and diagnostic applications Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-08 Marianna Rossetti, Erica Del Grosso, Simona Ranallo, Davide Mariottini, Andrea Idili, Alessandro Bertucci, Alessandro Porchetta
The emerging field of RNA nanotechnology harnesses the versatility of RNA molecules to generate nature-inspired systems with programmable structure and functionality. Such methodology has therefore gained appeal in the fields of biosensing and diagnostics, where specific molecular recognition and advanced input/output processing are demanded. The use of RNA modules and components allows for achieving diversity in structure and function, for processing information with molecular precision, and for programming dynamic operations on the grounds of predictable non-covalent interactions. When RNA nanotechnology meets bioanalytical chemistry, sensing of target molecules can be performed by harnessing programmable interactions of RNA modules, advanced field-ready biosensors can be manufactured by interfacing RNA-based devices with supporting portable platforms, and RNA sensors can be engineered to be genetically encoded allowing for real-time imaging of biomolecules in living cells. In this article, we report recent advances in RNA-based sensing technologies and discuss current trends in RNA nanotechnology-enabled biomedical diagnostics. In particular, we describe programmable sensors that leverage modular designs comprising dynamic aptamer-based units, synthetic RNA nanodevices able to perform target-responsive regulation of gene expression, and paper-based sensors incorporating artificial RNA networks.
Enantioseparation of chiral β-blockers using polynorepinephrine-coated nanoparticles and chiral capillary electrophoresis Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-08 Jia Wu, Xue Xiao, Zhenqun Li, Li Jia
A method of combining magnetic solid-phase separation (MSPE) and chiral capillary electrophoresis (CE) is developed for enantioseparation of trace amounts of β-blockers. Polynorepinephrine-functionalized magnetic nanoparticles (polyNE-MNPs) are synthesized and applied to simultaneously extract three β-blockers (carteolol, metoprolol, and betaxolol). The prepared polyNE-MNPs are spherical with a diameter of 198 ± 17 nm and the thickness of the polyNE coating is about 14 nm. PolyNE possesses abundant catechol hydroxyl and secondary amine groups, endowing the MNPs with excellent hydrophilicity. Under the optimum conditions, the extraction efficiencies of polyNE-MNPs for β-blockers are in the range of 89.6 to 100%, with relative standard deviations (RSDs) below 3.5%. The extraction process can be finished in 4 min. Field-enhanced sample injection (FESI) in chiral CE is constructed to further enhance the sensitivities of β-blocker enantiomers. The limits of detection for β-blocker enantiomers by the FESI-CE with polyNE-MNPs are in the range of 0.401 to 1.59 ng mL−1. The practicability of this method in real samples is evaluated by analysis of human urine samples. The recoveries for each enantiomer of β-blockers in the real samples range from 89.5 to 92.8%, with RSDs ranging from 0.37 to 5.9%. The whole detection process can be finished in less than 0.5 h. The method demonstrates its great potential in the pharmacokinetic and pharmacodynamic studies of chiral drugs in humans.
Determination of the polyphenolic fraction of Pistacia vera L. kernel extracts by comprehensive two-dimensional liquid chromatography coupled to mass spectrometry detection Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-08 Katia Arena, Francesco Cacciola, Domenica Mangraviti, Mariosimone Zoccali, Francesca Rigano, Nino Marino, Paola Dugo, Luigi Mondello
Pistachio (Pistacia vera L.) belongs to the Anacardiaceae family and it is a small tree species. It is native of the Middle East and Central Asia, but currently, it is cultivated also in California and in some Mediterranean countries, such as Greece and Italy. The most important pistachio producers are Iran, the USA, and Turkey. Besides being a delicious nut, pistachio, due to its wholesome nutritional properties, could be considered as a functional food. According to the results of several studies, pistachios have been proven to have various groups of valuable phytochemicals such as anthocyanins, flavan-3-ols, proanthocyanidins, flavonols, isoflavones, flavanones, stilbenes, and phenolic acids, possessing excellent biological activities. The most common analytical technique employed for their analysis is represented by liquid chromatography coupled to photodiode array and mass spectrometry detection. However, conventional LC can present some limits especially in terms of resolving power. In this contribution, as a powerful alternative, comprehensive two-dimensional liquid chromatography (LC×LC) was applied to the determination of the polyphenolic fraction of pistachio kernels from different geographical origins. A 150-mm micro-bore cyano column (2.7 μm dp) and 50-mm superficially porous C18 silica column (2.7 μm dp) in the first (1D) and second (2D) dimensions were employed, respectively. For boosting orthogonality, a shift 2D gradient was investigated leading to an increase in the overall peak capacity. The newly developed LC×LC method showed satisfactory linearity, sensitivity, precision and accuracy, which was then applied to sample quantitative analysis. A total of 51 different polyphenolic compounds were determined in the four samples investigated and 18 out of them are hereby reported for the first time.
Solid-phase extraction of estrogens and herbicides from environmental waters for bioassay analysis—effects of sample volume on recoveries Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-08 Eszter Simon, Andrea Schifferli, Thomas B. Bucher, Daniel Olbrich, Inge Werner, Etiënne L. M. Vermeirssen
Ecotoxicological screening of surface waters can involve multiple analyses using multiple bioassay and chemical analytical methods that require enriched samples to reach low concentrations. Such broad screening of the same sample necessitates sufficient sample volume—typically several liters—to produce a sufficient amount of enriched sample. Often, this is achieved by performing parallel solid-phase extractions (SPE) where extracts are combined into a pool—this is a laborious process. In this study, we first validated our existing SPE method for the chemical recovery of an extended set of compounds. We spiked four estrogenic compounds and 11 herbicides to samples from independent rivers (1 L) and wastewater treatment plant effluents (0.5 L). Then, we investigated the effect of increased sample loading of the SPE cartridges on both chemical and biological recoveries by comparing the validated volumes with four times larger sample volumes (i.e., 4 L river water and 2 L effluent). Samples were analyzed by LC-MS/MS and three bioassays: an estrogen receptor transactivation assay (ERα-CALUX), the combined algae test, and a bacterial bioluminescence inhibition assay. Our existing SPE method was found to be suitable for enriching the extended set of estrogens and herbicides in river water and effluents with near to perfect chemical recoveries (~ 100%), except for the herbicide metribuzin (46 ± 19%). In the large volume river and effluent samples, the biological activities and concentrations of the spiked compounds were between 87 and 104% of those measured with the lower sample loading, which is adequate. In addition, the ratio between the large and original volume SPE method for the non-target endpoint (bacterial bioluminescence inhibition) was acceptable (on average 82 ± 9%). Results indicate that our current water extraction method can be applied to up to four times larger sample volumes, resulting in four times more extract volumes, without significant reductions in recoveries for the tested estrogens and herbicides.
A novel optical approach for determination of prolactin based on Pr-MOF nanofibers Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-08 Sheta M. Sheta, Said M. El-Sheikh, Mokhles M. Abd-Elzaher
The analytical quantification and follow-up of the hormone prolactin is very important in clinical diagnosis (e.g., in cases of breast cancer), treatment, and the medical laboratory. The development of a new simple, fast, and less costly method is of considerable importance. Novel praseodymium metal–organic framework nanofibers (Pr-MOF-NFs) were synthesized by a facile and simple method for the determination of human prolactin in serum samples. The Pr-MOF-NFs were well characterized with several spectroscopic tools, such as mass spectrometry, Fourier transform IR spectroscopy, UV–vis spectroscopy, elemental analysis, X-ray diffraction, field-emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. The photoluminescence of Pr-MOF-NFs was investigated, and the results revealed that Pr-MOF-NFs could be used as a sensitive and selective nanofiber optical sensor for the detection of human prolactin. The calibration graph was studied over a wide prolactin concentration range of 0–200 ng/mL, with limits of detection and quantitation of 0.276 and 0.838 ng/mL, respectively, lower than the values mentioned in previous reports. The correlation coefficient was 0.9792. Moreover, the Pr-MOF-NFs were applied successfully for the detection of serum human prolactin at clinically applicable concentrations without interference from several types of hormones and various interfering analytes.
Nanobody: outstanding features for diagnostic and therapeutic applications Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-08 J.-Pablo Salvador, Lluïsa Vilaplana, M.-Pilar Marco
Nanobodies (Nbs) have arisen as an alternative to conventional antibodies (Abs) and show great potential when used as tools in different biotechnology fields such as diagnostics and therapy. Different approaches have been described for the production of Nbs and these methods face new challenges focused on improving yield, affinity, and reducing production costs. This review summarizes these challenges, and also the latest advances in the detection of different kinds of molecules, such as proteins and small molecules, and describes their potential use for noninvasive in vivo imaging and for in vitro assays. Moreover, the unique properties of Nbs are outlined like internalization, size, thermal and chemical stability, affinity, blood clearance, and labeling procedures. Concerning therapeutic applications, we highlight some already reported examples about Nbs being used for the treatment of several diseases such as cancer, neurodegenerative or infectious diseases among others. Finally, future trends, opportunities, and disadvantages are also discussed.
DNA-modulated photosensitization: current status and future aspects in biosensing and environmental monitoring Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-08 Yanying Wang, Zhen Dong, Hao Hu, Qing Yang, Xiandeng Hou, Peng Wu
Recently, photosensitized oxidation has been explored in many fields of research and applications, such as photodynamic therapy (PDT) and photodynamic antimicrobial chemotherapy (PACT). Although the photosensitized generation of ROS features emerging applications, controllable management of the photosensitization process is still sometimes problematic. DNA has long been considered the carrier for genetic information. With the in-depth study of the chemical properties of DNA, the molecular function of DNA is gradually witnessed by the scientific community. Undoubtedly, the selective recognition nature of DNA endows them excellent candidate modulators for photosensitized oxidation. According to current research, reports on DNA regulation of photosensitized oxidation can be roughly divided into two categories in principle: P-Q quenching pair-switched photosensitization and host-guest interaction-switched photosensitization. In this review, the development status of these two analytical methods will be summarized, and the future development direction of DNA-modulated photosensitization in biosensing and environmental monitoring will also be prospected.
A high-throughput metabolomics approach for the comprehensive differentiation of four Pulsatilla Adans herbs combined with a nontargeted bidirectional screen for rapid identification of triterpenoid saponins Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-08 Wendan Zhang, Honghong Jiang, Jianxi Yang, Gengshen Song, Di Wen, Wenqiao Liu, Miaomiao Jin, Qiao Wang, Yingfeng Du, Qian Sun, Liang Cao, Huijun Xu
Pulsatilla Adans (PSA) herbs (Ranunculaceae) have been widely used in traditional medicine in China and other countries. However, the authentication and quality control of PSA herbs have always been a challenging task due to their similar morphological characteristics and the diversity of the multiple components that exist in the complicated matrix. Herein, a novel integrated strategy combining UHPLC/Q-Orbitrap-MS techniques with chemometrics analysis is proposed for the discrimination of PSA materials. We developed a comprehensive method integrating a nontargeted bidirectionally screened (NTBDS) MS data set and a targeted extraction peak area analysis for the characterization of triterpenoid saponins of PSA from different species. After that, partial least-squares discriminant analysis (PLS-DA) was performed on the obtained MS data set and the parameter variable importance for the projection (VIP) value and P value were employed to screen the valuable MS features to discriminate PSA from different species. In addition, the receiver operating characteristic (ROC) curve is used to verify the reliability of MS features. Finally, heatmap visualization was employed to clarify the distribution of the identified triterpenoid saponins, and four medicinal species of PSA were successfully differentiated. Additionally, 34 constituents were reported in PSAs for the first time, 81 triterpenoid saponins were identified as differential components, and 12 chemical ingredients were characterized as potential chemical markers to differentiate the four officinal PSA herbs. This is the first time that the differences in different PSA herbs have been observed systematically at the chemical level. The results suggested that using the identified characteristic components as chemical markers to identify different PSA herbs was effective and viable. This method provides promising perspectives in the analysis and identification of the ingredients of Chinese herbal medicines, and the identification of similar herbs from the same species.
An integrated proteomic and glycoproteomic study for differences on glycosylation occupancy in rheumatoid arthritis Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-07 Xu Li, Lang Ding, Xue Li, He Zhu, Ebtesam A. Gashash, Zhanguo Li, Peng George Wang, Cheng Ma
Rheumatoid arthritis (RA) is an autoimmune disease in which certain immune cells are dysfunctional and attack their own healthy tissues. There has been great difficulty in finding an accurate and efficient method for the diagnosis of early-stage RA. The present shortage of diagnostic methods leads to the rough treatments of the patients in the late stages, such as joint removing. Nowadays, there is an increasing focus on glyco-biomarkers discovery for malicious disease via MS-based strategy. In this study, we present an integrated proteomics and glycoproteomics approach to uncover the pathological changes of some RA-related glyco-biomarkers and glyco-checkpoints involved in the RA onset. Among 39 distinctly expressive N-glycoproteins, 27 N-glycoproteins were discovered with over twofold expression significances. On the other hand, 13 proteins have been distinguished with significant differences in 53 distinctly expressed proteins identified in this study. Such an integrated approach will provide a comprehensive strategy for new potential glyco-biomarkers and checkpoints discovery in rheumatoid arthritis.
Comparison of operator- and computer-controlled scanning electron microscopy of particles from different atmospheric aerosol types Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-06 Stine Eriksen Hammer, Martin Ebert, Stephan Weinbruch
Individual aerosol particles from an urban background site in Mainz (Germany), a traffic hotspot site in Essen (Germany), the free troposphere in the Swiss Alps (high altitude research station Jungfraujoch), a rural background/marine site on Cyprus (Cyprus Atmospheric Observatory) and a rural background site in the forested area of Odenwald (Germany) were characterised with two different scanning electron microscopy techniques, operator controlled (opSEM) and computer controlled (ccSEM). For all samples, about 500 particles were investigated by opSEM, and between 1103 and 6940 particles by ccSEM. Large systematic differences (in some cases a factor up to ~ 20) in the abundance of the various particle groups are observed in the results of the two techniques. These differences are dependent on particle type and size. With ccSEM, information on the mixing state of particles (e.g., presence of heterogeneous inclusions, surface coatings or gradients in chemical composition) cannot be obtained, and particle groups which are recognised by their complex morphology (e.g., soot and fly ash particles) are classified into other particle groups. In addition, highly volatile particles (i.e., particles which evaporate under electron bombardment within seconds) will be overlooked by ccSEM. If these limitations of ccSEM are not considered, normalising the particle group abundances to 100% (a popular practise in many publications) may lead to drastic misinterpretation of the real aerosol composition. OpSEM is indispensable when detailed information of particle composition is required, although it suffers from a much higher expenditure of time. In conclusion, both techniques might be used for single particle characterisation as long as drawbacks of each are considered.
Quantitative and rapid detection of amantadine and chloramphenicol based on various quantum dots with the same excitations Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-05 Sanlei Xie, Kai Wen, Sihan Wang, Jianyi Wang, Tao Peng, Ghulam Mujtaba Mari, Jiancheng Li, Zhanhui Wang, Xuezhi Yu, Haiyang Jiang
Herein, we developed a sensitive and quantitative flow assay for simultaneous detection of amantadine (AMD) and chloramphenicol (CAP) in chicken samples based on different CdSe/ZnS quantum dots (QDs). In contrast to other reports, the QDs could be excited by the same excitations that lowered the requirements for the matching instruments. Under the optimal conditions, the strategy permitted sensitive detection of AMD and CAP in a linear range of 0.23 to 1.02 ng/g and 0.02 to 0.66 ng/g. The limits of detection were 0.18 ng/g and 0.016 ng/g, respectively. Moreover, the whole detection process could be completed within 20 min with no additional sophisticated instruments and complicated operations. Spiked samples were analyzed using both QD-based lateral flow immunoassay (QD-LFIA) and commercial ELISA kits with good correlation (R2 = 0.96). Moreover, this study laid the foundation and simplified the development of the requisite instrument.
Label-free detection of exosomes using a surface plasmon resonance biosensor Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-05 Abu Ali Ibn Sina, Ramanathan Vaidyanathan, Alain Wuethrich, Laura G. Carrascosa, Matt Trau
The development of a sensitive and specific detection platform for exosomes is highly desirable as they are believed to transmit vital tumour-specific information (mRNAs, microRNAs, and proteins) to remote cells for secondary metastasis. Herein, we report a simple method for the real-time and label-free detection of clinically relevant exosomes using a surface plasmon resonance (SPR) biosensor. Our method shows high specificity in detecting BT474 breast cancer cell–derived exosomes particularly from complex biological samples (e.g. exosome spiked in serum). This approach exhibits high sensitivity by detecting as low as 8280 exosomes/μL which may potentially be suitable for clinical analysis. We believe that this label-free and real-time method along with the high specificity and sensitivity may potentially be useful for clinical settings.
Carbon isotope compositions of whole wine, wine solid residue, and wine ethanol, determined by EA/IRMS and GC/C/IRMS, can record the vine water status—a comparative reappraisal Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-04 Jorge E. Spangenberg, Vivian Zufferey
Recently, we reported that the carbon isotope composition of the solid residues obtained by freeze-drying white and red wines (δ13CWSR) could be used for tracing the water status of the vines whose grapes were used to produce them. Here, we compare different methods using δ13C values of other wine components, particularly those of whole wine (δ13CWW) obtained by elemental analysis and isotope ratio mass spectrometry (EA/IRMS) and of wine ethanol (δ13CWEtOH) obtained by gas chromatography/combustion/IRMS (GC/C/IRMS), for their suitability to assess the vine water status. The studied wines were obtained from field-grown cultivars (Vitis vinifera L. cv. Chasselas, Petite Arvine, and Pinot noir) under different water treatments during the 2009–2014 seasons and were the same wines in which the δ13CWSR was measured previously. The EA/IRMS method for whole wine used two successive EA analytical cycles in each acquisition period to reduce the residence time of the sample capsules in the autosampler. The sample aliquots for the EA/IRMS and GC/C/IRMS analyses were optimized for peak-size differences less than 10% between the sample and reference gas. For all wine varieties, the δ13CWW and δ13CWEtOH values were linearly correlated with the predawn leaf water potential (Ψpd) and therefore serve as reliable indicators of vine water status, as do the δ13C values for must sugars and wine solid residues. The strongest negative correlations with Ψpd were for δ13Csugars (r = −0.94, n = 54) and δ13CWEtOH (r = −0.91) and were lower but still highly significant (p < 0.00001) for δ13CWW (r = −0.71) and δ13CWSR (r = −0.70). An evaluation of the advantages and drawbacks of the different methods is presented, showing that the δ13C analysis of wine ethanol by GC/C/IRMS is the most appropriate.
Fast liquid chromatography-tandem mass spectrometry methodology for the analysis of alkylphenols and their ethoxylates in wastewater samples from the tank truck cleaning industry Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-04 Mélanie Mignot, Maarten Nagels, Sven Poelmans, Alexander Kensert, Jan Dries, Raf DewiI, Deirdre Cabooter
A fast methodology to quantify 4-tert-octylphenol (4-t-OP) and 4-nonylphenol (4-NP) and their mono- and di-ethoxylates was developed, validated, and applied to real wastewater samples. Dispersive liquid-liquid microextraction was employed as a sample preparation step, leading to a pre-concentration factor of roughly 30. Analysis was carried out by liquid chromatography-tandem mass spectrometry with electrospray ionisation in multiple reaction monitoring mode. Average recoveries were generally between 80 and 120% for both the alkylphenols and their mono- and di-ethoxylates in influent and effluent wastewater. A minimum of 5 concentration levels per compound, ranging between 1 and 500 ng/mL, were prepared to construct calibration curves making use of isotopically labelled internal standards. The method presented good linearity and repeatability over the whole range of concentrations. Taking into account the concentration factor, and the recovery of the compounds, lower limits of quantification obtained in effluent wastewater were 0.04 ng/mL for 4-t-OP and 0.14 ng/mL for 4-NP, complying with European regulations, and between 0.03 ng/mL and 0.39 ng/mL for the ethoxylates. In influent wastewater, these limits were slightly higher. The total run time of 5 min for the alkylphenols and 8 min for the ethoxylates ensured high throughput. The developed method was applied to determine 4-t-OP and 4-NP and their mono- and di-ethoxylates in wastewater from several tank truck cleaning companies, which was subjected to ozonation and/or biological treatment. It was demonstrated that ozonation was best applied after the biological treatment, since in this case, the biological treatment could degrade most of the biodegradable organic matter, after which ozone could react directly with the recalcitrant organic pollutants. In this case, the concentrations of the target compounds in the wastewater of the investigated company decreased below the legally allowed concentration of the European water legislation.
A new boronic acid reagent for the simultaneous determination of C 27 -, C 28 -, and C 29 -brassinosteroids in plant tissues by chemical labeling-assisted liquid chromatography-mass spectrometry Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-04 Lei Yu, Wen-Jing Cai, Tiantian Ye, Yu-Qi Feng
Brassinosteroids (BRs) are endogenous plant growth-promoting hormones affecting growth and development during the entire life cycle of plants. Naturally occurring BRs can be classified into C27-, C28-, or C29-BRs based on the nature of the alkyl groups occupying the C-24 position in the side chain of the 5a-cholestane carbon skeleton. However, while C27-BRs exhibit similar bioactivities to C28- and C29-BRs, the biosynthetic pathways of C27-BRs in plants have not yet been clearly characterized. In addition to a lack of biochemical and enzymatic evidence regarding the biosynthetic pathways of C27-BRs, even most of the intermediate compounds on their pathways have not been explored and identified due to the lower endogenous levels of C27-BRs. Therefore, the development of highly sensitive analytical methods is essential for studying the biosynthetic pathways and physiological functions of C27-BRs. Accordingly, this study establishes qualitative and quantitative methods for identifying and detecting C27-, C28-, and C29-BRs using a newly synthesized boronic acid reagent denoted as 2-methyl-4-phenylaminomethylphenylboronic acid (2-methyl-4-PAMBA) in conjunction with liquid chromatography-mass spectrometry (LC-MS). Labeling with 2-methyl-4-PAMBA provides derivatives with excellent stability, and the detection sensitivities of BRs, particularly for C27-BRs, are dramatically improved. The limits of detection (with a signal-to-noise ratio of 3) for six BRs, including 2 C27-BRs (28-norCS and 28-norBL), 3 C28-BRs (CS, BL, and TY), and a single C29-BR (28-homoBL), are found to be 0.10–1.68 pg/mL after labeling with 2-methyl-4-PAMBA. Finally, the proposed analytical method is successfully applied for the detection of endogenous BRs in small mass samples of Oryza sativa seedlings, Rape flowers, Arabidopsis shoots, and Arabidopsis flowers. In addition, a method for profiling potential BRs in plants is also developed using LC-MS in multiple reaction monitoring scan mode assisted by 2-methyl-4-PAMBA and 2-methyl-4-PAMBA-d5 labeling. The developed method is able to identify 10 potential BRs in a Rape flower extract. The proposed quantitative and qualitative methods established by 2-methyl-4-PAMBA labeling are helpful for facilitating an understanding of the physiological functions and biosynthetic pathways of BRs, particularly for C27-BRs.
Rapid determination of isocitrate dehydrogenase mutation status of human gliomas by extraction nanoelectrospray using a miniature mass spectrometer Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-02 Fan Pu, Clint M. Alfaro, Valentina Pirro, Zhuoer Xie, Zheng Ouyang, R. Graham Cooks
Isocitrate dehydrogenase (IDH) I and II mutations in gliomas cause an abnormal accumulation of 2-hydroxyglutarate (2-HG) in these tumor cells. These mutations have potential prognostic value in that knowledge of the mutation status can lead to improved surgical resection. Information on mutation status obtained by immunohistochemistry or genomic analysis is not available during surgery. We report a rapid extraction nanoelectrospray ionization (nESI) method of determining 2-HG. This should allow the determination of IDH mutation status to be performed intraoperatively, within minutes, using a miniature mass spectrometer. This study demonstrates that the combination of tandem mass spectrometry with low-resolution mass spectrometry allows this analysis to be performed with confidence.
Toward an efficient workflow for the analysis of the human milk peptidome Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-02 Kelly A. Dingess, Henk W. P. van den Toorn, Marko Mank, Bernd Stahl, Albert J. R. Heck
There is a growing interest for investigating endogenous peptides from human biofluids which may provide yet unknown functional benefits or provide an early indication of disease states as potential biomarkers. A major technical bottleneck in the investigation of endogenous peptides from body fluids, e.g., serum, urine, saliva, and milk, is that each of these fluids seems to require unique workflows for peptide extraction and analysis. Thus, protocols optimized for serum cannot be directly translated to milk. One biofluid that is readily available, but which has not been extensively explored, is human milk, whose analysis could contribute to our understanding of the immune development of the newborn infant. Due to the occurrence of highly abundant lipids, proteins, and saccharides, milk peptidomics requires dedicated sample preparation steps. The aim of this study was to develop a time and cost-efficient workflow for the analysis of the human milk peptidome, for which we compared peptide extraction methodologies and peptide fragmentation methods. A method using strong acid protein precipitation and analysis by collision-induced dissociation fragmentation was found to be superior to all other test methods, allowing us qualitative and quantitative detection of about 4000 endogenous human milk peptides in a total analysis time of just 18 h.
Development and application of water-compatible molecularly imprinted polymers for the selective extraction of carbamazepine from environmental waters Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-02 Porkodi Kadhirvel, Audrey Combès, Louis Bordron, Valérie Pichon
A molecularly imprinted polymer (MIP) was designed in order to allow the selective solid-phase extraction of carbamazepine (CBZ), an anticonvulsant and mood-stabilizing drug, at ultra-trace level from aqueous environmental samples. A structural analog of CBZ was selected as a dummy template and different synthesis conditions were screened. The selectivity of the resulting imprinted polymers was evaluated by studying the retention of CBZ in a solvent similar to the one used for the synthesis. The presence of imprinted cavities in the polymers was then demonstrated by comparing the elution profiles (obtained by using MIP and a non-imprinted polymer, NIP, as a control) of the template, of CBZ, and of a structural analog of CBZ. Then, the extraction procedure was further optimized for the treatment of aqueous samples on the two most promising MIPs, with special attention being paid to the volume and composition of the percolation and washing solutions. The best MIP provided a highly selective retention in tap water with 81% extraction recovery for CBZ in the elution fraction of the MIP and only 14% for NIP. The repeatability of the extraction procedure was demonstrated for both tap and river waters (RSD below 4% in river water) for the drugs CBZ, oxcarbamazepine, and one metabolite (carbamazepine 10,11-epoxide). A MIP capacity of 1.15 μmol g−1 was determined. Finally, an analytical procedure involving the MIP was developed allowing the detection of CBZ at a concentration level of only a few nanograms per liter in river water. The selectivity provided by the MIP resulted in a 3000-fold increase of the signal-to-noise ratio in LC/MS analysis as compared to the use of conventional sorbent.
Advanced methods for microRNA biosensing: a problem-solving perspective Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-02 Roberta D’Agata, Giuseppe Spoto
MicroRNAs (miRNAs) present several features that make them more difficult to analyze than DNA and RNA. For this reason, efforts have been made in recent years to develop innovative platforms for the efficient detection of microRNAs. The aim of this review is to provide an overview of the sensing strategies able to deal with drawbacks and pitfalls related to microRNA detection. With a critical perspective of the field, we identify the main challenges to be overcome in microRNA sensing, and describe the areas where several innovative approaches are likely to come for managing those issues that put limits on improvement to the performances of the current methods. Then, in the following sections, we critically discuss the contribution of the most promising approaches based on the peculiar properties of nanomaterials or nanostructures and other hybrid strategies which are envisaged to support the adoption of these new methods useful for the detection of miRNA as biomarkers of practical clinical utility.
Correction to: Comparison of turn-on and ratiometric fluorescent G-quadruplex aptasensor approaches for the detection of ATP Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-01 Sathya Srinivasan, Velu Ranganathan, Maria C. DeRosa, Bhaskar Mohan Murari
Regrettably, before online publication the figure of Scheme 2 has been pasted twice as Scheme 1.
Fabrication of micro-patterned substrates for plasmonic sensing by piezo-dispensing of colloidal nanoparticles Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-01 Angelina Pittner, Sebastian Wendt, David Zopf, André Dathe, Norman Grosse, Andrea Csáki, Wolfgang Fritzsche, Ondrej Stranik
In this work we describe a very fast and flexible method for fabrication of plasmon-supporting substrates with micro-patterning capability, which is optimized for plasmonic sensing. We combined a wet chemistry approach to synthesize metallic nanoparticles with a piezo-dispensing system enabling deposition of nanoparticles on the substrates with micrometer precision. In this way, an arbitrary pattern consisting of 200 μm small spots containing plasmonic nanostructures can be produced. Patterns with various nanoparticles exhibiting different plasmonic properties were combined, and the surface density of the particles could be easily varied via their solution concentrations. We showed that under controlled conditions the dispensing process caused no aggregation of the particles and it enabled full transfer of the colloidal solutions onto the substrate. This is an important condition, which enables these substrates to be used for reliable plasmonic sensing based on monitoring the spectral shift of the nanoparticles. We demonstrated the functionality of such substrates by detection of small protein adsorption on the spots based on plasmon label-free sensing method.
Critical evaluation of the use of total reflection X-ray fluorescence spectrometry for the analysis of whole blood samples: application to patients with thyroid gland diseases Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-01 Eva Marguí, Jasna Jablan, Marko Gerić, Suzana Inić, Ana-Marija Domijan, Renato Janušić, Božena Šarčević, Ignasi Queralt, Verica Garaj-Vrhovac
Multielemental analysis of whole blood can provide significant information for the evaluation of nutritional status and diagnosis of certain diseases as well as for the assessment of exposure to potentially toxic metals. However, the quantification of multiple elements in whole blood is not easy partly because of the wide variation in element concentrations (from ng L−1 to g L−1) and the complex matrix. The aim of this work was to develop a fast, sustainable, and reliable analytical method, in combination with low-power TXRF, for multielemental analysis of blood samples. Firstly, a set of experiments were carried out to select the best diluent type and dilution factor using the control material SeronormTM Trace Elements Whole Blood L-1. A critical evaluation of the parameters affecting the sample deposition on the reflector was also carried out including a study of the shape and element distribution of the deposited residue on the reflector by micro X-ray fluorescence spectrometry. Using the best analytical conditions, limits of detection estimated were in the low milligrams per kilogram range and similar to those obtained using more complex sample treatments such as digestion. Accuracy and precision of the results were in most cases acceptable (recoveries 89–102%, RSD 6–8%, n = 5). Only underestimated values were obtained for light elements such as potassium. To prove the applicability of the method, several blood samples from control and thyroid disease patients were analyzed. Despite the fact that more samples need to be analyzed, it seems that Zn and Br contents in some of the patients are significantly higher compared to control samples.
A multichannel microchip containing 16 chambers packed with antibody-functionalized beads for immunofluorescence assay Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-02-01 Si Peng, Tingting Hong, Wenbin Liang, Wenfang Liu, Chuanpin Chen
A multichannel chip containing 16 microchambers was developed for fast and sensitive immunoassays. In each chamber, antibody-functionalized nonmagnetic beads were applied as the solid phase to capture target antigens. Four types of IgGs (human, rabbit, chicken, and mouse) could be detected simultaneously by our combining this microchip with a sandwich immunoassay technique. A three-layer chip structure was investigated for integration of multiple processes, including washing, immune reaction, and detection, in one microchip. Moreover, the proposed chip design could improve batch-to-batch repeatability and avoid interferences between different channels without the preparation of complex microvalves. The total operation time of this system was less than 30 min, with a desirable detection limit of 0.2 pg/mL. The results indicate that the microfluidic platform is promising for the immunoassay of multiple clinical biomarkers.
The behavior of a bipedal DNA walker moving on the surface of magnet microparticles and its application in DNA detection Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-28 Ningxing Li, Mingyuan Du, Songbai Tian, Xinghu Ji, Zhike He
In this work, a three-dimensional DNA machine based on the isothermal strand-displacement polymerase reaction (ISDPR) has been constructed. The walking behavior of a DNA walker on the obstructive surface of magnetic beads has also been studied by adding different nucleic acid blocks. The “leg” of the DNA walker could hybridize with a hairpin structure DNA named H1 and lead to the opening of it. And the newly exposed stem would interact with a primer. A strand exchange has happened with the assistance of polymerase and dNTPs, so that the “leg” has been displaced and the DNA walker could be pushed to move on the surface. But the nucleic acid blocks could increase steric hindrance and obstruct this process, which is similar to the behavior of human beings walking on craggy paths. Through changing these blocks, such as the structure, the amount, and the length of blocks, the movement of the DNA walker has been controlled. What’s more, the results of its application for DNA detection are satisfactory. The limit of detection is 21.6 pM. Also, this method has been successfully applied in complex biological samples.
Application of direct analysis in real time to the study of chemical vapor generation mechanisms: identification of intermediate hydrolysis products of amine-boranes Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-28 Lucia D’Ulivo, Enea Pagliano, Massimo Onor, Zoltan Mester, Alessandro D’Ulivo
In order to elucidate controversial results emerging in chemical vapor generation (CVG) for trace element determination, we conducted a series of experiments devoted to the identification of intermediates formed by acid hydrolysis of amine-boranes. For the first time, direct analysis in real time coupled with high-resolution mass spectrometry (DART-Orbitrap) was applied for detection of this class of compounds. Mass spectra of both solid amine-boranes and their aqueous solutions (pH ~ 8, no hydrolysis) were acquired for understanding their ionization pathway. Mass spectra of aqueous solutions of t-BuNH2·BH3 and Me2NH·BH3 were acquired under conditions that are employed in CVG (0.017–4.0 mol L−1 HCl, 0.167–0.2 mol L−1 borane reagent). The results disclose a reactivity driven by pH of amine-boranes undergoing hydrolysis. At low acidity, the hydrolysis proceeds according to the currently accepted displacement mechanisms (i.e., R3N·BH3 + H3O+ → R3NH+ + H2OBH3). At higher acidity, N-tert-butyl, cyclotriborazane, and bis(dimethylamino)boronium were identified, for the first time, during the hydrolysis of t-BuNH2·BH3 and Me2NH·BH3, respectively. Formation of these intermediates was ascribed to a hydrolysis pathway starting with the ionization of the amine-borane, (i.e., R3N·BH3 + H3O+ → [(H2O)R3NBH2] + + H2). The new evidence explains the anomalous behavior observed in CVG by amine-borane derivatization, and updates the currently accepted mechanisms for the acid hydrolysis of amine-boranes.
Simultaneous metabolic mapping of different anatomies by 1 H HR-MAS chemical shift imaging Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-28 Alan Wong, Covadonga Lucas-Torres
Localized information on a specimen is considered indispensable for deciphering biological activity. Magnetic resonance spectroscopy is a notable method because of its versatility; however, one limitation is the spectral quality on a static sample. This study explores an amalgamated method with two magnetic resonance experiments: high-resolution magic-angle spinning (HR-MAS) for high-quality spectral acquisition from a spinning sample and chemical shift imaging (CSI) for spatial localization. The advantage of HR-MAS CSI is its amenity for simultaneously profiling the metabolome—with good spectral data—at different spatial regions in a single experiment. Herein, 1H HR-MAS CSI (including a T2-contrast CSI) was described and performed on various food tissues and an intact organism. Different data analyses such as multivariate and quantification were explored to identify the metabolic variants in different anatomical regions and in one case, to assist in a spatial allocation. The limitation and drawback of the experiment are also discussed.
Critical assessment of two sample treatment methods for multiresidue determination of veterinary drugs in milk by UHPLC-MS/MS Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-26 Delia Castilla-Fernández, David Moreno-González, Miriam Beneito-Cambra, Antonio Molina-Díaz
In this work, two sample treatment procedures have been evaluated for the determination of veterinary drug residues in milk. In order to cover a wide range of polarities, a total of 66 veterinary drugs with log Kow ranging from − 1 to 5 were selected. Two sample cleanup steps, (i) dispersive solid-phase extraction (dSPE) using enhanced matrix removal lipid as sorbent and (ii) solid-phase extraction (in pass-through mode) using Oasis HLB PRiME cartridges, were critically assessed in terms of sample throughput, recovery, matrix effect, cleanliness of extracts, limit of quantification, and repeatability. The veterinary drugs tested (viz. benzimidazoles, cephalosporins, imidazothiazoles, macrolides, NSAIDs, penicillins, quinolones, steroids, sulfonamides, and β-agonists) were analyzed by ultra-high-performance liquid chromatography tandem mass spectrometry. According to the results, both methods exhibited similar recovery rates between 70 and 120% for most of compounds tested. Matrix effects were satisfactory for both methodologies, although the tolerance to matrix effects was slightly higher with HLB PRiME with nearly negligible matrix effects in most cases. Limits of quantitation were also well below the current maximum residue levels established by the European Union. Notably, sample throughput was higher in the case of HLB PRiME, since this pass-through SPE cleanup approach involved fewer steps than the EMR-Lipid dSPE approach. The results in terms of analysis time, sensitivity, precision, cleanliness of extracts, and matrix effect showed the suitability of both procedures for the monitoring of veterinary drugs residues in milk samples in a single run.
Long noncoding RNAs: from genomic junk to rising stars in the early detection of cancer Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-26 Rebeca Miranda-Castro, Noemí de-los-Santos-Álvarez, María Jesús Lobo-Castañón
Despite having been underappreciated in favor of their protein-coding counterparts for a long time, long noncoding RNAs (lncRNAs) have emerged as functional molecules, which defy the central dogma of molecular biology, with clear implications in cancer. Altered expression levels of some of these large transcripts in human body fluids have been related to different cancer conditions that turns them into potential noninvasive cancer biomarkers. In this review, a brief discussion about the importance and current challenges in the determination of lncRNAs associated to cancer is provided. Different electrochemical nucleic acid-based strategies for lncRNAs detection are critically described. Future perspectives and remaining challenges for the practical implementation of these methodologies in clinical medicine are also discussed.
Metal–organic framework-based affinity materials in proteomics Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-25 Adeela Saeed, Dilshad Hussain, Shafaq Saleem, Sehrish Mehdi, Rabia Javeed, Fahmida Jabeen, Muhammad Najam-ul-Haq
Metal–organic frameworks (MOFs) are an eminent addition to materials science research because of their versatile properties due to which their applications are wide spread in proteomics. They are used in various fields due to their characteristics like higher surface area, specific symmetry, ease of modification, and availability of a variety of ligands. As affinity sorbents, they have shown higher selectivity, sensitivity, and reproducibility than conventionally used materials. They are applied for the enrichment of phosphopeptides, glycopeptides, low mass peptides, and as laser desorption/ionization (LDI) matrices for small-molecule analysis. This review captures the insight of applying MOFs in the field of mass spectrometry-based proteomics. The specific features are discussed regarding MOFs as affinity sorbents for the selective capture of biological molecules like phosphopeptides and glycopeptides from complex samples. The potential of MOFs as LDI mass spectrometry (LDI-MS) matrices for small-molecule analysis is also evaluated. MOFs have also been used as enzymatic reactors for the digestion of proteins, prior to MS analysis. MOF-based affinity materials and bioreactors reduce proteome complexity and improve detection sensitivity and coverage. Size-exclusion effects of MOFs help in subtracting the abundant proteins in peptidomics. Several limitations of MOFs are addressed, which include stability under varying pH conditions, the unclear interaction mechanism between the MOFs and targeted analytes, and the non-specific binding that interferes during the analysis because of metal centers and ligands in the MOFs. This will open up MOF-based research to overcome the limitations and improve the performance of MOFs as selective and sensitive materials.
A simple, fast method for the analysis of 20 contaminants of emerging concern in river water using large-volume direct injection liquid chromatography-tandem mass spectrometry Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-25 Josep Borrull, Agustí Colom, Josepa Fabregas, Eva Pocurull, Francesc Borrull
A fast and sensitive method for the determination of a structurally and physico-chemically diverse group of contaminants of emerging concern (CEC) based on large-volume direct injection liquid chromatography-tandem mass spectrometry was developed. The method can be used to determine 20 CECs belonging to different pollutant families (pharmaceuticals, personal care products, and pesticides) in river water at nanogram per liter. A single analytical run is required and the positive and negative ionization modes can be used simultaneously. Because of the large-volume injections of samples and the high sensitivity of the current mass spectrometers, the method has no need of a preconcentration step. The analytes are quantitated with matrix-matched calibration curves. The estimated limits of detection were in the range 0.1–5 ng L−1. The accuracy of the method was in the range 86–114%, and the precision, expressed as a relative standard deviation (RSD %), was below 18% for all the analytes (n = 5, at 5, 10, and 25 ng L−1). The method was applied to water samples taken from different points along the lower course of the Ebro River, Spain. A total of 12 out of the 20 target analytes were detected, and the ones at higher concentrations were caffeine and the pharmaceuticals paracetamol and ibuprofen (184.8 ng L−1, 63.3 ng L−1, and 23.3 ng L−1, respectively).
Non-target data acquisition for target analysis (nDATA) of 845 pesticide residues in fruits and vegetables using UHPLC/ESI Q-Orbitrap Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-25 Jian Wang, Willis Chow, Jon W. Wong, Daniel Leung, James Chang, Mengmeng Li
A non-target data acquisition for target analysis (nDATA) workflow based on accurate mass measurements using UHPLC/ESI Q-Orbitrap full MS-data-independent acquisition and a compound database was developed to screen pesticide residues in fruit and vegetable samples. The compound database of 845 pesticides was built from dd-MS2 (data-dependent acquisition) product ion spectral data and LC retention times of individual pesticide standards. MS2 spectra of samples were acquired using multiplexing data-independent acquisition (mDIA) and variable data-independent acquisition (vDIA). Screening of pesticides in samples was based on either the retention time (± 0.5 min) and the mass accuracy (± 5 ppm) of a precursor (RTP by full MS) or the retention time (± 0.5 min) and the mass accuracy (± 5 ppm) of a precursor and its fragment ion (RTFI by full MS/DIA). In validation studies involving mDIA and vDIA analysis of 10 fruits and vegetables spiked with pesticides prior to QuEChERS sample preparation, RTP correctly found up to 765 and 796 pesticides at 10 and 100 μg/kg, respectively, whereas RTFI correctly identified up to 729 and 764 pesticides at the same respective concentrations. UHPLC/ESI Q-Orbitrap full MS/mDIA or vDIA proved to be a comprehensive detection technique and has potential for pesticide residue screening in fruits and vegetables.
Delineating the tumor margin with intraoperative surface-enhanced Raman spectroscopy Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-25 Chunhuan Jiang, Ying Wang, Wei Song, Lehui Lu
The failure of complete tumor resection during cancer surgery is a leading cause of lethal recurrence and metastasis. However, achieving accurate delineation of tumor margins intraoperatively remains extremely difficult because the infiltrated nature of a tumor usually gives an obscure margin and spreading microtumors. Recent studies show that surface-enhanced Raman scattering (SERS) has the potential to depict precisely the actual tumor extent with high sensitivity, specificity, and spatial resolution; thus providing a promising platform to improve the therapeutic efficiency. In this review, we discuss the recent progress in the use of SERS spectroscopy for intraoperative image-guided resection. We highlight key successes in the development of SERS tags and give insights into the design mechanism of rational SERS tags. We also discuss how to improve the performance of intraoperative navigation based on SERS and explore the challenges and future opportunities for the development of a more effective SERS-based platform.
In situ analysis and imaging of aromatic amidine at varying ligand densities in solid phase Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-24 Christian J. Ortiz-Hernandez, Adriana N. Santiago-Ruiz, Adaliz J. Torres-Rosado, Jomarie Jiménez-Gonzalez, Sean B. Yeldell, Rolando Oyola, Ivan J. Dmochowski, Jose Sotero-Esteva, Vibha Bansal, Ezio Fasoli
We report the development of a fast and accurate fluorescence-based assay for amidine linked to cellulose membranes and Sepharose gel. The assay is founded on the glyoxal reaction, which involves reaction of an amidine group with glyoxal and an aromatic aldehyde, leading to the formation of a fluorophore that can be analyzed and quantified by fluorescence spectroscopy and imaging. While the assay has been reported previously for aromatic amidine estimation in solution phase, here we describe its adaptation and application to amidine linked to diverse forms of solid matrices, particularly benzamidine Sepharose and benzamidine-linked cellulose membranes. These functionalized porous matrices find important application in purification of serine proteases. The efficacy of a protein separation device is determined by, among other factors, the ligand (amidine) density. Hence, a sensitive and reproducible method for amidine quantitation in solid phase is needed. The glyoxal reaction was carried out on microbead-sized Sepharose gel and cellulose membranes. Calibration curves were developed for each phase, which established linearity in the range of 0–0.45 μmol per mL amidine for free amidine in solution, 0–0.45 μmol amidine per mL Sepharose gel, and 0–0.48 μmol per mL cellulose membrane. The assay showed high accuracy (~ 3.4% error), precision (RSD < 2%), and reproducibility. Finally, we show how this fluorescent labeling (glyoxal) method can provide a tool for imaging membranes and ligand distribution through confocal laser scanning microscopy.
In vitro assessment of pediococci- and lactobacilli-induced cholesterol-lowering effect using digitally enhanced high-performance thin-layer chromatography and confocal microscopy Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-24 Rohawi Nur Syakila, Siong Meng Lim, Snezana Agatonovic-Kustrin, Fei Tieng Lim, Kalavathy Ramasamy
The cholesterol-lowering properties of 12 lactic acid bacteria (LAB) in the absence or presence of 0.3% bile salts were assessed and compared quantitatively and qualitatively in vitro. A new, more sensitive and cost-effective high-performance thin-layer chromatography method combined with digital image evaluation of derivatised chromatographic plates was developed and validated to quantify cholesterol in LAB culture media. The performance of the method was compared with that of the o-phthalaldehyde method. For qualitative assessment, assimilated fluorescently tagged cholesterol was visualised by confocal microscopy. All LAB strains exhibited a cholesterol-lowering effect of various degrees (19–59% in the absence and 14–69% in the presence of bile salts). Lactobacillus plantarum LAB12 and Pentosaceus pentosaceus LAB6 were the two best strains of lactobacilli and pediococci. They lowered cholesterol levels by 59% and 54%, respectively, in the absence and by 69% and 58%, respectively, in the presence of bile salts. Confocal microscopy showed that cholesterol was localised at the outermost cell membranes of LAB12 and LAB6. The present findings warrant in-depth in vivo study.
Entacapone detection by a GOQDs-molecularly imprinted silica fluorescent chemical nanosensor Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-23 Hamed Ahmadi, Farnoush Faridbod, Mina Mehrzad-Samarin
A sensitive fluorescent chemical nanosensor for the detection of entacapone (EN) in pharmaceutical samples is introduced. EN is a nitrocatechol drug that functions as a selective and reversible inhibitor of catechol-O-methyl transferase and is widely prescribed in the treatment of Parkinson disease. Molecularly imprinting technology and graphene oxide quantum dots (GOQDs) were employed in designing the EN fluorescent nanosensor. GOQDs were embedded into an inorganic polymer while the imprinting process occurred. The synthesized GOQDs-embedded silica molecularly imprinting polymer (SMIP) showed strong fluorescent emission at 450 nm by exciting at 360 nm. The fluorescence intensity of GOQDs-embedded SMIP was quenched effectively by adsorption of EN as a template molecule. The quenching corresponded to EN concentration in a linear range of at least 0.40–6.00 μM with a limit of detection of 0.31 μM. The designed chemical nanosensor was successfully applied to the analysis of entacapone in some pharmaceutical tablets also containing carbidopa and levodopa (RSD 3.8%).
Synthesis and purification of biotinylated oligodeoxynucleotides containing single TpT dimeric pyrimidine (6-4) pyrimidone lesion Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-22 Danni Wu, Ning Zhang, Bingjie Kong, Haiying Hang, Hailin Wang
Ultraviolet (UV) radiation could induce pyrimidine-related dimeric lesions in genomic DNA. Though the cyclobutane pyrimidine dimers (CPDs) are the most abundant UV-induced lesions, the pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) may have more serious, potentially lethal, and mutagenic effects. It is important to have 6-4PP-containing oligodeoxynucleotides to be prepared for studying their adverse biological effects. Here, we developed a UV-irradiated water droplet method for the preparation of a biotinylated, 6-4PP-containing 10-mer oligodeoxynucleotide. By the use of HPLC purification and enrichment twice, the final yield is estimated to be about 8.1%. In contrast, without applying droplet technique, the direct UV irradiation against oligonucleotide-containing aqueous solution, the product yield is very low. The enzymatic hydrolyzation of the obtained product shows a 6-4PP characteristic ion transition of 545.12 → 432.13 in negative ion mode UHPLC-Q-TOF/MS. The established procedure for the preparation of 6-4PP-containing oligonucleotides is convenient with an improved yield.
Gas chromatography–mass spectrometry of sapucainha oil ( Carpotroche brasiliensis ) triacylglycerols comprising straight chain and cyclic fatty acids Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-22 Habtewold D. Waktola, Chadin Kulsing, Yada Nolvachai, Claudia M. Rezende, Humberto R. Bizzo, Philip J. Marriott
Sapucainha oil, which may be used to treat leprosy, comprises straight chain and cyclic fatty acids (FA), and triacylglycerols (TAG). The FA and TAG content of the oil sample was analysed using gas chromatography–electron ionisation mass spectrometry (GC–EIMS). FA analysis was performed after derivatisation to fatty acid methyl esters (FAME). For free FA and TAG analysis, the oil sample was dissolved in hexane and injected into a short, high-temperature column, for GC with MS analysis. Free FA and FAME were tentatively identified based on mass spectrum information of their molecular and fragment ions, as well as library matching. Overlapping TAG peaks were deconvoluted based on mass fingerprint data. The FA composition was utilised to predict possible TAG identities. FA residues of TAG were identified based on characteristic fragment ions, such as [M–RCO2]+, [RCO+128]+, [RCO+74]+ and RCO+ where R is the aliphatic hydrocarbon chain. FAME analysis showed that the cyclic FA hydnocarpic (36.1%), chaulmoogric (26.5%) and gorlic (23.6%) acids were the major components. In addition, straight chain FA such as palmitic, palmitoleic, stearic, oleic and linoleic acids were detected. Palmitic, oleic, hydnocarpic, chaulmoogric and gorlic acids were also detected as free FA in the oil sample. Six groups of TAG peaks were eluted from GC at temperatures ≥330 °C. After deconvolution and mass spectrum analysis, each TAG peak group was revealed to comprise 2 to 5 co-eluted TAG molecules; >18 TAG were identified. These TAG consisted of a mix of both cyclic and straight chain FA, but were mostly derived from cyclic FA.
Cost-effective imprinting to minimize consumption of template in room-temperature ionic liquid for fast purification of chlorogenic acid from the extract of E. ulmoides leaves Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-22 Ya Kun Sun, Guang-Ying Sun, Man Jia, Jian Yang, Zhao-Sheng Liu, Yan-Ping Huang, Haji Akber Aisa
One of the main challenges in large-scale applications of molecularly imprinted polymers (MIPs) is the significant amount of template needed in polymer preparation. A new strategy based on room-temperature ionic liquids (RTILs) was suggested to solve this problem by reducing the amount of template in the polymerization recipe. The MIP was synthesized with a mixture of dimethyl sulfoxide and RTIL (1-butyl-3-methylimidazolium tetrafluoroborate) as porogen, in which chlorogenic acid (CGA) was used as template, 4-vinylpyridine (4-VP) as functional monomer, and ethylene glycol dimethacrylate (EDMA) as cross-linker. The influence of polymerization variables, including CGA concentrations, and the ratio of 4-VP to EDMA on imprinting effect were investigated comprehensively. Moreover, the properties involving the column permeability, the number of binding sites, and the polymer morphology of the CGA-MIP monoliths were studied thoroughly. The MIP monolith had an excellent column permeability (1.53 × 10−13 m2) and allowed an ultra-fast on-line SPE, which dramatically shortens the separation time (< 10 min) and improves the separation efficiency. At high flow velocity (5.0 mL min−1), 50 μL of the extract from Eucommia ulmoides leaves can be loaded directly on the CGA-MIP monoliths and CGA with high purity can be obtained with a recovery of 89.01 ± 0.05%. As a conclusion, the resulting RTIL-induced approach of preparing MIP may be an effective tool in fabricating MIP in a low-cost way.
Multicolor bioluminescence resonance energy transfer assay for quantification of global DNA methylation Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-19 Yuji Baba, Kaho Yamamoto, Wataru Yoshida
Abnormal DNA methylations such as hypermethylation on tumor suppressor genes and global hypomethylation have been recognized as hallmarks of cancer. Previously, we reported a bioluminescence resonance energy transfer (BRET)-based global DNA methylation level assay using a methyl-CpG-binding domain-fused firefly luciferase (MBD-Fluc) and unmethylated CpG-binding domain-fused firefly luciferase (CXXC-Fluc). The BRET signal between MBD-Fluc and BOBO-3 DNA intercalating dye depends on the methylated CpG contents, whereas the BRET signal between CXXC-Fluc and BOBO-3 depends on the unmethylated CpG contents. Therefore, the global DNA methylation level can be quantified using the BRET assay. However, these assays must be performed separately, because the same luciferase fuses to both MBD and CXXC. In this study, we developed a one-step quantification assay of global DNA methylation based on a multicolor BRET assay using MBD-Fluc and CXXC-fused Oplophorus luciferase (CXXC-Oluc). We demonstrated that MBD-Fluc and CXXC-Oluc simultaneously excite BOBO-3 and BOBO-1 DNA intercalating dyes on genomic DNA, respectively. Moreover, the BRET signals produced from MBD-Fluc and CXXC-Oluc depended on the methylation status of the CpG contents. These results demonstrate that global DNA methylation can be quantified by this multicolor BRET assay in a single tube.
Adenoviral detection by recombinase polymerase amplification and vertical flow paper microarray Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2018-11-29 Susanna Nybond, Pedro Réu, Samuel Rhedin, Gustav Svedberg, Tobias Alfvén, Jesper Gantelius, Helene Andersson Svahn
Respiratory viral infections often mimic the symptoms of infections caused by bacteria; however, restricted and targeted administration of antibiotics is needed to combat growing antimicrobial resistance. This is particularly relevant in low-income settings. In this work, we describe the use of isothermal amplification of viral DNA at 37 °C coupled to a paper-based vertical flow microarray (VFM) setup that utilizes a colorimetric detection of amplicons using functionalized gold nanoparticles. Two oligonucleotide probes, one in-house designed and one known adenoviral probe were tested and validated for microarray detection down to 50 nM using a synthetic target template. Furthermore, primers were shown to function in a recombinase polymerase amplification reaction using both synthetic template and viral DNA. As a proof-of-concept, we demonstrate adenoviral detection with four different adenoviral species associated with respiratory infections using the paper-based VFM format. The presented assay was validated with selected adenoviral species using the in-house probe, enabling detection at 1 ng of starting material with intra- and inter-assay %CV of ≤ 9% and ≤ 13%. Finally, we validate our overall method using clinical samples. Based on the results, the combination of recombinase polymerase amplification, paper microarray analysis, and nanoparticle-based colorimetric detection could thus be a useful strategy towards rapid and affordable multiplexed viral diagnostics.
Silver nanoflowers-enhanced Tb(III)/La(III) co-luminescence for the sensitive detection of dopamine Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-15 Chongmei Sun, Jin Shen, Rongwei Cui, Fangzheng Yuan, Hui Zhang, Xia Wu
A sensitive fluorescent analytical method for the detection of dopamine (DA) was developed based on surface-enhanced Tb(III)/La(III) co-luminescence using silver nanoflowers (AgNFs). Anisotropic AgNFs show strong surface-enhanced fluorescence effect owing to the abundant sharp tips. Tb(III)/La(III)-DA complexes mainly bind to the sharp tips of AgNFs and thus shorten the distance between the complexes. The shortened distance gives rise to obvious surface-enhanced Tb(III)/La(III) co-luminescence effect. In this work, AgNFs offer many superior properties, such as enhanced intrinsic green fluorescence of Tb(III) (λex/λem = 310/546 nm), increased fluorescence lifetime, and improved energy transfer efficiency. Under the optimum conditions, the fluorescence intensity is linearly correlated with the concentration of DA in the range of 0.80–10 nM (R2 = 0.9970), and the detection limit is 0.34 nM (S/N = 3). The fluorescent nanoprobe was successfully applied to the determination of DA in human serum samples with recoveries ranging from 99.1 to 102.6%.
Photoluminescent Ag nanoclusters for reversible temperature and pH nanosenors in aqueous solution Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-14 Yanyan Zhang, Xiaohong Guo, Gao Li, Guomei Zhang
A facile, straightforward, and green method was reported for the preparation of water-soluble and highly luminescent silver nanoclusters (AgNCs) using captopril (Capt) as a stabilizing agent. The as-prepared Capt@AgNCs exhibited bright red emission with a strong peak centered at 637 nm and showed low toxicity and good stability. Interestingly, the AgNCs displayed temperature sensitivity based on obvious temperature dependence of the fluorescence emission intensity. Furthermore, the AgNCs showed a good reversible and linear response to the environment temperature over the range from 10 °C to 45 °C with a high resolution and activation energy, which allowed its potential application as a fluorescent nanothermometer. In addition, the AgNCs were prepared to monitor pH via the fluorescence intensity of AgNCs responding sensitively to pH fluctuating within a wide range from 2.08 to 6.06. The study provides promising applications as a convenient and eco-friendly fluorescent temperature and pH nanosenser in environmental and biological fields.
Development and validation of a glass-silicon microdroplet-based system to measure sulfite concentrations in beverages Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-14 Yannick Vervoort, Rodrigo Sergio Wiederkehr, Michiel Smets, Maarten Fauvart, Tim Stakenborg, Gabrielle Woronoff, Liesbet Lagae, Kevin J. Verstrepen
Sulfite is often added to beverages as an antioxidant and antimicrobial agent. In fermented beverages, sulfite is also naturally produced by yeast cells. However, sulfite causes adverse health effects in asthmatic patients and accurate measurement of the sulfite concentration is therefore very important. Current sulfite analysis methods are time- and reagent-consuming and often require costly equipment. Here, we present a system allowing sensitive, ultralow-volume sulfite measurements based on a reusable glass-silicon microdroplet platform on which microdroplet generation, addition of enzymes through chemical-induced emulsion destabilization and pillar-induced droplet merging, emulsion restabilization, droplet incubation, and fluorescence measurements are integrated. In a first step, we developed and verified a fluorescence-based enzymatic assay for sulfite by measuring its analytical performance (LOD, LOQ, the dynamic working range, and the influence of salts, colorant, and sugars) and comparing fluorescent microplate readouts of fermentation samples with standard colorimetric measurements using the 5,5′-dithiobis-(2-nitrobenzoic acid) assay of the standard Gallery Plus Beermaster analysis platform. Next, samples were analyzed on the microdroplet platform, which also showed good correlation with the standard colorimetric analysis. Although the presented platform does not allow stable reinjection of droplets due to the presence of a tight array of micropillars at the fluidics entrances to prevent channel clogging by dust, removing the pillars, and integrating miniaturized pumps and optics in a future design would allow to use this platform for high-throughput, automated, and portable screening of microbes, plant, or mammalian cells.
Potassium triiodide-quenched gold nanocluster as a fluorescent turn-on probe for sensing cysteine/homocysteine in human serum Anal. Bioanal. Chem. (IF 3.307) Pub Date : 2019-01-14 John Nebu, J. S. Anjali Devi, R. S. Aparna, B. Aswathy, G. M. Lekha, George Sony
A fluorescent sensing platform using KI3-quenched bovine serum albumin stabilized gold nanoclusters has been designed and used as a fluorescent probe for the turn-on detection of homocysteine/cysteine (Cys/Hcy). The fluorescence of gold nanoclusters was quenched by iodine. The fluorescence of quenched gold nanoclusters was effectively switched on by Cys/Hcy devoid of the interference of glutathione. The transmission electron microscopy image, X-ray photoelectron spectroscopy analysis, time-correlated single photon counting analysis, and dynamic light scattering data confirmed the aggregation-induced quenching of fluorescence of gold nanoclusters by iodine. The turn-on response of Cys/Hcy shows two linear ranges from 0.0057 to 5 μM and from 8 to 25 μM, with a limit of detection of 9 nM for cysteine and 12 nM for homocysteine. Real samples were analyzed to monitor Cys/Hcy added to human serum. The fluorescence turn-on response of the probe on a paper strip in the presence of Cys/Hcy was studied.
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