显示样式:     当前期刊: Analytica Chimica Acta    加入关注       排序: 导出
我的关注
我的收藏
您暂时未登录!
登录
  • Nitrogen doped chiral carbonaceous nanotube for ultrasensitive DNA direct electrochemistry, DNA hybridization and damage study
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-12
    Mengjing Cui, Qiuyue Zhao, Qi Zhang, Mingxuan Fu, Yuexian Liu, Xinyu Fan, Haiyang Wang, Yufan Zhang, Huan Wang

    In the interest of developing novel electrocatalyst for high performance DNA biosensing, with distinctive chiral double helix nanostructure, nitrogen doped chiral carbonaceous nanotube (Chiral-CNT) was employed for ultrasensitive label-free DNA biosensing research. Chiral-CNT can quantitative detection of four DNA bases with high sensitivity and selectivity. Without any prehydrolysis and labeling process, direct electrochemistry of single-stranded DNA and double-stranded DNA, qualitative and quantitative detection of DNA hybridization (low detection limit: 0.0268 g L-1) were realized. Moreover, sensitive detection of DNA damage induced by fenton reagent was also realized with low detection limit of 0.0350 mg mL-1 and high sensitivity of 7.42 μA mg mL-1. The high biosensing performance attributes to the unique chiral structure of Chiral-CNT, leads to efficient interreaction between Chiral-CNT and DNA molecule.

    更新日期:2018-07-14
  • ε-MnO2-modified graphite electrode as a novel electrochemical sensor for the ultrasensitive detection of the newly FDA approved Hepatitis C antiviral drug ledipasvir
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-11
    Fatma A.M. Abdel-aal, Azza H. Rageh, Mohamed I. Said, Gamal A. Saleh

    A novel, simple and sensitive electrochemical method for the determination of ledipasvir (LED), the newly FDA approved Hepatitis C antiviral drug was developed and validated using ε-MnO2-modified graphite electrode. Two different MnO2 polymorphs (γ- and ε-MnO2 nanoparticles) were synthesized and characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA). Surface area measurements show that ε-MnO2 NPs have large surface area of 345 m2/g, which is extremely high if compared to that of γ-MnO2 NPs (38 m2/g). In addition, a comprehensive study of the difference in the electrochemical behavior of LED while using pencil graphite electrode (PGE) modified with either γ- or ε-MnO2 NPs is carried out. It was found that surface area and percentage of surface hydroxyls of MnO2 NPs are the key factors governing the sensitivity of the fabricated electrode toward the oxidation of the positively charged LED. Scanning electron microscopy (SEM) was employed to investigate the morphological shape of MnO2 NPs and the surface of the bare and modified electrodes. Moreover, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for the surface analysis of the modified electrodes. Based on the obtained results, ε-MnO2/PGE was applied as a selective and sensitive electrode for determination of LED. Under the optimized experimental conditions, ε-MnO2/PGE provides a linear response over the concentration range of 0.025–3.60 μmol L−1 LED with a low limit of detection, which was found to be 5.10 nmol L−1 (4.50 ng mL−1) for the 1st peak and 9.20 nmol L−1 (8.10 ng mL−1) for the 2nd one. In addition, the oxidation behavior of LED is discussed with a full investigation of the oxidized product using FT-IR and LC/MS. The fabricated sensor exhibits a good precision, selectivity and stability and was applied successfully for the determination of LED in its tablets and real rat plasma samples with a good recovery using a simple extraction technique.

    更新日期:2018-07-12
  • Dual-functional polymer-modified magnetic nanoparticles for isolation of lysozyme
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-11
    Mingming Zhang, Juan Qiao, Li Qi

    An artificial receptor approach for proteins capture and release was designed based on ionic-sensitive and thermo-sensitive functionalized polymers, which were modified onto the surface of magnetic nanoparticles. The dual-functional poly(styrene-sulfonate-N-isopropylacrylamide) (P(SS-NIPAm)) was synthesized via the free radical polymerization method and used as the artificial receptor with electrostatic, hydrophilic and hydrophobic properties. The affinity between the artificial receptor and lysozyme was investigated using high performance liquid chromatography. Arising from the strong and specific interactions between the negatively charged sulfonic acid groups of P(SS-NIPAm) and positively charged amino groups of the protein, the prepared artificial receptor exhibited outstanding affinity for lysozyme. Interestingly, due to the thermo-responsive and ionic strength-responsive features of the prepared P(SS-NIPAm), the capture and release process for lysozyme could be modulated by varying the environmental temperature and ionic strength. Further, the proposed artificial receptor based on P(SS-NIPAm) modification of magnetic nanoparticles surface was used for affinity capture of lysozyme in human serum with a recovery ranging from 89.9% to 100.4%, paving a new way for synthesis of artificial receptors and showing great potential for recognition of target protein in real bio-samples.

    更新日期:2018-07-12
  • A photoswitchable “host-guest” approach for the selective enrichment of dimethoate from olive oil
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-11
    Raquel Garcia, Elisabete P. Carreiro, João P. Prates Ramalho, Anthony J. Burke, João C. Lima, Marco D.R. Gomes da Silva, Ana Maria Costa Freitas, Maria João Cabrita

    This work describes the development of a new selective photocontrollable molecularly imprinted-based sorbent for the selective enrichment/pre-concentration of dimethoate from spiked olive oil samples. To achieve this goal an improved molecularly imprinted strategy relying on the embedding of a functional monomer containing an azobenzene chromophore as light-responsive element, on the crosslinked tridimensional molecular imprinted network, has been assessed. To address the mechanisms underlying template recognition and uptake/release of the analyte from the functional imprinted material, computational studies using a quantum chemical approach, have been explored. This new functional sorbent provides a straightforward controllable uptake/release of the target template using light as the stimuli tool, which is highly advantageous due to light manipulation characteristics, such as superior clean, precision and remote controllable properties. In general, this work will contribute to the implementation of a photoswitchable analytical methodology that proves to be suitable for the selective isolation and further quantification of dimethoate from spiked olive oil matrices at levels similar to the maximum residues limits imposed by the legislation. The limits of detection, calculated based on 3σ, was 1.6 mgL−1 and the limit of quantification, based on 10σ, was 5.2 mgL−1. The implemented sample preparation shows high reproducibility and recoveries (93.3 ± 0.4%).

    更新日期:2018-07-12
  • A New Bifunctional Nanostructure Based on Two‐Dimensional Nanolayered of Co(OH)2 Exfoliated Graphitic Carbon Nitride as a High Performance Enzyme-Less Glucose Sensor: Impedimetric and Amperometric Detection
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-11
    Javad Tashkhourian, Sayedeh Fatemeh Nami-Ana, Mojtaba Shamsipur

    A novel non-enzymatic glucose sensor was constructed based on the nanolayered Co(OH)2 deposited on polymeric graphitic carbon nitride (Co(OH)2-g-C3N4) via chemical bath deposition. The two‐dimensional nanocomposite was used to modify a carbon paste electrode and its electrochemical performance of electrode was carefully evaluated. The electrochemical oxidation of glucose at modified electrode was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 0.2 M KOH. It revealed a remarkable electrocatalytic behavior and noticeably synergistic effect as a result of decent exfoliation of graphitic carbon nitride in the presence of Co(OH)2. The amperometric response achieved by the modified electrode showed two calibration ranges with an excellent selectivity. A single-frequency impedance method was applied for glucose determination as an alternative to conventional EIS methods. The developed sensor represents a high sensitivity, wide concentration range (25 μM - 420.0 mM by impedimetry and 6.6-9800 μM by amperometry), and high reproducibility. The modified electrode showed a good selectivity for glucose over potentially interfering materials such as dopamine, ascorbic acid, urea, and uric acid. Finally, the Co(OH)2-g-C3N4-CPE was utilized for quantification of glucose in blood serum samples.

    更新日期:2018-07-12
  • Point discharge microplasma reactor for high efficiency conversion of H2S to SO2 for speciation analysis of sulfide and sulfite using molecular fluorescence spectrometry
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-11
    Huimin Yu, Jing Hu, Xiaoming Jiang, Xiandeng Hou, Yunfei Tian

    A low temperature plasma integrating the merits of small size, simple operation and rich active particles has good performance in analytical chemistry. In this work, a point discharge microplasma was used as a reactor to facilitate the gaseous conversion reaction from H2S to SO2 with an excellent efficiency as high as 95%. By coupling this reactor with a fluorescence spectrometer, the speciation analysis of sulfide and sulfite was achieved in a simple, chromatographic separation-free, time-saving and practical way. Specifically, with the discharge off, only sulfite was quantified; with discharge on, both sulfide and sulfite were quantified; and with a simple subtraction, the speciation analysis could be easily attained. By the acidification process, a limit of detection of 7.7 μM by the proposed method was obtained for both sulfide and sulfite in aqueous medium, and this method was successfully utilized to analysis of real samples.

    更新日期:2018-07-12
  • Hairpin-structured probe conjugated nano-graphene oxide for the cellular detection of connective tissue growth factor mRNA
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-11
    Min Wang, Christian Wiraja, Meiling Wee, David Yeo, Lianzhe Hu, Chenjie Xu

    Identification of abnormal scars at their early stage has attracted increasing attentions as the scars can only be assessed qualitatively and subjectively upon maturity, when no invasive procedure is involved. This report introduces a fluorescent probe that targets a potential abnormal scar biomarker (connective tissue growth factor (CTGF) mRNA) in skin fibroblasts. This probe is constructed of hairpin-structured probes (HPs) targeting CTGF mRNA and the nano-graphene oxide (nano-GO) base. The HPs are non-covalently absorbed on the surface of nano-GO, which pre-quenches the fluorescence of HPs. Close proximity of complementary CTGF mRNA would lead to preferential HP hybridization and dissociation from nano-GO, which restores the fluorescence signal from HPs. Utilizing this probe, we can distinguish abnormal fibroblasts derived from abnormal scars and assess the effectiveness of anti-scarring drugs like Repsox and transforming growth factor-beta type I receptor (TGF-βRI) siRNA.

    更新日期:2018-07-12
  • LED based near infrared spectral acquisition for multiwavelength analytical ultracentrifugation: A case study with gold nanoparticles
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-11
    Joseph Pearson, Helmut Cölfen

    A pulsed light emitting diode, coupled with a properly configured spectrometer is implemented in open source analytical ultracentrifugation detection hardware, allowing for spectral acquisition spanning the visible to near infrared. Details of the challenges arising with the new hardware are described, along with the necessary solutions to overcome them. The system is successfully tested with polystyrene and gold nanoparticles, demonstrating effectiveness for different material and particle geometries. Sedimentation coefficient distributions and analytically extracted spectra are presented for the multiwavelength datasets extending into the near infrared. Additionally, deconvolution algorithms are applied as a further demonstration of tools applicable to these datasets and the resolving power possible. The results of gold nanoparticle analysis presented here show effective near infrared spectral acquisition is now possible for multiwavelength analytical ultracentrifugation, opening the door for analysis of many important samples with spectral properties in this range, including rich classes of metal and semiconductor nanoparticles.

    更新日期:2018-07-12
  • Electrochemical screening of single nucleotide polymorphisms with significantly enhanced discrimination factor by an amplified ratiometric sensor
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-12
    Baoting Dou, Jin Li, Bingying Jiang, Ruo Yuan, Yun Xiang

    The detection of single nucleotide polymorphisms (SNPs) is of great clinical significance to the diagnosis of various genetic diseases and cancers. In this work, the development of an ultrasensitive ratiometric electrochemical sensor for screening SNP with a significantly enhanced discrimination factor is reported. The ferrocene (Fc) and methylene blue (MB) dual-tagged triple helix complex (THC) probes are self-assembled on the gold electrode to construct the sensing interface. The addition of the mutant p53 gene causes the disassembly of the THC probes with the release of the Fc-tagged sequence and the folding of the MB-labeled sequence into a hairpin structure, causing the change in the current response ratio of MB to Fc for monitoring the mutant p53 gene. Such ratio is dramatically enhanced by the toehold-mediated displacement reaction-assisted target recycling amplification with the presence of an assistance hairpin sequence. With the significant signal amplification and the advantageous specificity of the THC probes, sub-femtomolar detection limit and a highly enhanced SNP discrimination factor for the mutant p53 gene can be obtained. Besides, the proof-of-demonstration application of the sensor for diluted real samples has been verified, offering such sensor new opportunities for monitoring various genetic related diseases.

    更新日期:2018-07-12
  • Direct sample injection from a syringe needle into a separation capillary
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-12
    František Opekar, Petr Tůma

    An automatic micro-injector was developed for electrophoretic analysis of a microlitre amount of clinical samples, enabling injection of the sample from a Hamilton syringe. The outlet of the syringe needle is located directly opposite the inlet of the separation capillary at a defined distance of the order of hundreds of μm in the injection space. During the injection, the background electrolyte is forced out by air from this space and a drop of the sample is forced out of the syringe by a micro-pump so that it is caught at the entrance to the capillary. From the drop the sample is injected into the capillary by applying a negative pressure pulse or simply by spontaneous injection. The injection space is then filled with background electrolyte, which washes away excess sample and separation is commenced. The injector was tested in electrophoretic separation of a model sample with equimolar concentrations of 100 μM NH4+, K+, Na+, Mg2+ and Li+ in a short capillary with total/effective length of 16.5/11.5 cm. The repeatability of the migration time and peak area expressed as the RSD value is 2% and 4%, respectively. The practical applicability of the injector was verified on the determination of the antiparasitic pentamidine in 10 μL of rat plasma. Electrophoretic separation of pentamidine was performed in 100 mM of acetic acid/NaOH at pH 4.55, the sample consumption per analysis is 125 nL, the separation time is 45 s and the attained LOQ using contactless conductivity detection is 8 μM.

    更新日期:2018-07-12
  • Development of a self-priming PDMS/paper hybrid microfluidic chip using mixed-dye-loaded loop-mediated isothermal amplification assay for multiplex foodborne pathogens detection
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-12
    Bo Pang, Kaiyue Fu, Yushen Liu, Xiong Ding, Jiumei Hu, Wenshuai Wu, Kun Xu, Xiuling Song, Juan Wang, Ying Mu, Chao Zhao, Juan Li

    Foodborne pathogen is the primary cause of foodborne disease outbreak. Given its great damage, a sensitive, simple and rapid detection method is demanded. Herein, we described a self-priming polydimethylsiloxane (PDMS)/paper hybrid microfluidic chip, termed SPH chip, with mixed-dye-loaded loop-mediated isothermal amplification (LAMP) for multiplex foodborne pathogens detection. Staphylococcus aureus (SA) and Vibrio parahaemolyticus (VP) were chosen to verify the novel method. Compared to other similar detection devices, the SPH chip required easier fabrication process, less operation steps and lower cost. Additionally, the reaction result, especially for the weak-positive reaction, could be judged more accurately and conveniently due to the use of mixed-dye. Without pre-enrichment of bacteria in the food contaminated sample, the limit of detection (LOD) reached down to 1000 CFU mL−1 with high specific. Additionally, for fully exploiting the potential of SPH chip, a conceptual eight-channel detection chip was also developed. Overall, the reliable and excellent result demonstrated that the novel method had great potential to be applied in the wider range of pathogens detection or disease diagnose, especially in some resource-limited area.

    更新日期:2018-07-12
  • Core-shell red silica nanoparticles based immunochromatographic assay for detection of Escherichia coli O157:H7
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-09
    Chunjie Zhu, Guangying Zhao, Wenchao Dou

    In this paper, a new type immunochromatographic assay (ICA) based on core-shell red silica nanoparticles (core-shell red SiO2NPs) was proposed and used to detect Escherichia coli O157:H7 (E. coli O157:H7). This is the first report of qualitative ICA for detecting E. coli O157:H7 in phosphate buffer saline (PBS) and food sample using core-shell red SiO2NPs. Monodispersed red SiO2NPs were synthesized in the aqueous solution by modifying amino silane and C.I Reactive Red 136 on unmodified silica nanoparticles. The limit of detection (LOD) of this core-shell red SiO2NPs based ICA for E. coli O157:H7 was 4.5 × 105 CFU/mL in sterile PBS within 20 min. The LOD of this ICA strip for E. coli O157:H7 in milk and pork samples both were 4.5 × 106 CFU/mL. The core-shell red SiO2NPs based ICA for detection of E. coli O157:H7 has no cross activity with other bacteria. All these results show that this new kind of core-shell colored SiO2NPs is promising for the practical applications in ICA and other rapid detection fields.

    更新日期:2018-07-09
  • A simple and sensitive fluorescence method for detection of telomerase activity using fusion protein bouquets
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-05
    Tao Wu, Yuanfu Zhang, Tingting Hou, Yinghong Zhang, Shuhao Wang

    Telomerase is considered as a widely accepted cancer biomarker for early cancer diagnostics. Herein, we develop a simple, ultrahigh sensitivity method for detection of telomerase activity, which relied on that RecA-GFP fusion proteins wrapped around telomeric DNA to form fluorescence bouquets. RecA-GFP fusion protein was synthesized through fusion protein technology. In the presence of telomerase, telomerase elongation products are wrapped around by RecA-GFP fusion protein to form big fluorescent bouquets, which resulted in strong fluorescence. This method has the linear range from 50 to 1000 HeLa cells and the detection limit is 8 HeLa cells, based on a signal-to-noise ratio (S/N) of 3. Compared with conventional methods, this method has the advantages of low toxicity, outstanding sensitivity, and excellent selectivity. Hence, it provides a promising approach for the detection of telomerase activity and diagnosis of cancer.

    更新日期:2018-07-08
  • Sensitive DNA detection by polymerase chain reaction with gold nanoparticles
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-05
    Li Zou, Ruidi Shen, Liansheng Ling, Gongke Li

    We developed a novel strategy for rapid colorimetric detection of specific DNA sequence based on gold nanoparticles assemblies induced by polymerase chain reaction (PCR) product. In the presence of target DNA, the two DNA-functionalized AuNP probes selectively hybridized with the prohibited nucleic acid segments of two primers owing to the zipping off of the hairpin structures during PCR process, resulted in the aggregation of AuNPs with a concomitant color change from red to blue-purple. It is a convenient and universal method for sensitive DNA detection with no need for any further post-treatment of the PCR products. Most importantly, our method showed a low limit of detection (LOD) of 4.3 fM with a wide range of target DNA from 16 fM to 1.6 nM. Owing to the versatility and low cost, the proposed strategy could be extremely useful for a wide range of applications, providing a promising tool for rapid disease diagnostics and gene sequencing.

    更新日期:2018-07-08
  • Ultra-high performance supercritical fluid chromatography in impurity control: Searching for generic screening approach
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-05
    Kateřina Plachká, František Švec, Lucie Nováková

    In this study, 63 compounds measured as 10 individual mixtures containing in each case an active pharmaceutical ingredient and its relevant impurities, and additional set of 7 basic beta blockers were analyzed using ultra-high performance supercritical fluid chromatography with UV and mass spectrometry detection. The separations were accomplished using 8 different stationary phases (diol, diethylamine, 2-picolylamine, 1-aminoanthracene, BEH 2-ethylpyridine, BEH, CSH pentafluorophenyl and HSS C18 SB), 6 modifiers (methanol, ethanol, isopropanol, methanol/acetonitrile, methanol/ethanol, ethanol/acetonitrile) and 5 additives in methanol (0.1% formic acid, 10 mmol/L ammonium formate, 10 mmol/L ammonium acetate, 0.4% ammonium hydroxide, and 2% water).

    更新日期:2018-07-08
  • Non-separative mass spectrometry methods for non-invasive medical diagnostics based on volatile organic compounds: A review
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-05
    Ana María Casas-Ferreira, Miguel del Nogal-Sánchez, José Luis Pérez-Pavón, Bernardo Moreno-Cordero

    In this review, an assessment of non-separative methods based on mass spectrometry used to analyse volatile organic compounds in the field of bioanalysis is performed. The use of non-separative methods based on mass spectrometry has been established as an attractive option for analysing compounds. These instrumental configurations are suitable for biomedical applications because of their versatility, rapid output of results, and the wide range of volatile organic compounds that can be determined.Here, techniques such as headspace sampling coupled to mass spectrometry, membrane introduction mass spectrometry, selected ion flow tube mass spectrometry, proton transfer reaction mass spectrometry, secondary electrospray ionization mass spectrometry and ion mobility mass spectrometry, are evaluated. Samples involving non-invasive methods of collection, such as urine, saliva, breath and sweat, are mainly considered. To the best of our knowledge, a comprehensive review of all the non-separative instrumental configurations applied to the analysis of gaseous samples from all matrices non-invasively collected has not yet been carried out.The assessment of non-separative techniques for the analysis of these type of samples can be considered a key issue for future clinical applications, as they allow real-time sample analysis, without patient suffering. Any contribution to the early diagnosis of disease can be considered a priority for the scientific community. Therefore, the identification and determination of volatile organic compounds related to particular diseases has become an important field or research.

    更新日期:2018-07-08
  • Dual-mode fluorescent and colorimetric immunoassay for the ultrasensitive detection of alpha-fetoprotein in serum samples
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-05
    Yaofeng Zhou, Xiaolin Huang, Sicheng Xiong, Xiangmin Li, Shengnan Zhan, Lifeng Zeng, Yonghua Xiong

    We present a novel dual-mode fluorescent and colorimetric immunosensor based on conventional immunoassay platforms by utilizing a gold nanoflower (AuNF)-loaded fluorescein molecule (AuNF@Fluorescein) as signal output. The AuNFs were modified with thiolated carboxyl ligand, which consisted of a hydrophobic alkane chain as hydrophobic wallet for fluorescein encapsulation, a tetra (ethylene glycol) unit for biocompatibility and solubility, and a functional carboxyl group for the conjugation of biorecognition molecules for biosensing. The resultant AuNFs showed a high loading capacity of 3.74 × 106 fluorescein molecules per AuNF because of its flower-like shape with many complex branches. By adjusting the solution pH to 8.0, the fluorescein molecules can almost entirely be released from the hydrophobic wallet of AuNF@Fluorescein, which led to strong fluorescent-signal amplification. Under the optimal detection conditions, the proposed immunoassay based on fluorescent signal exhibited ultrahigh sensitivity for alpha-fetoprotein (AFP) detection, with a limit of detection (LOD) of 29 fg/mL. This value is approximately 9.3 × 103-fold lower than that of corresponding horseradish peroxidase (HRP)-based immunoaasy (LOD = 270 pg/mL). The fluorescein molecule also had intrinsic peroxidase-like activity to catalyze 3,3′,5,5′-tetramethylbenzidine oxidation with hydrogen peroxide for colorimetric signal. The proposed method with colorimetric mode further exhibited a sensitivity with a LOD of 17.7 pg/mL, which is about 15-fold lower than that of conventional HRP-based immunoassay. The recoveries of the proposed dual-mode immunoassay for AFP spiked serum samples ranged within 89.85% to 100.0%, with the coefficient of variations ranging from 0.5% to 2.4%, indicating acceptable accuracy and precision for AFP quantitative detection. The reliability of the developed dual-mode immunoassay was further compared with a commercial chemiluminiscence immunoassay kit by analyzing 20 clinical serum samples, showing that the two methods well agreed with each other, with high correlation coefficients of 0.997 and 0.986 based on recorded fluorescence and colorimetric signals, respectively. In summary, the proposed method was highly suitable for the ultrasensitive analysis of biomarkers or infectious diseases by fluorescence mode and can be used for routine clinical diagnosis by colorimetric mode.

    更新日期:2018-07-08
  • Simultaneous observation of concurrent two-dimensional carbon and chlorine/bromine isotope fractionations of halogenated organic compounds on gas chromatography
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-06
    Caiming Tang, Jianhua Tan

    It has been reported that isotope fractionation can occur on gas chromatography (GC), yet little is known about concurrent dual-elements isotope fractionations on GC. Revelation of concurrent two-dimensional carbon and chlorine/bromine isotope fractionations of halogenated organic compounds (HOCs) on GC may be of important significance for compound-specific isotope analysis (CSIA). This study presents an in-depth investigation of the two-dimensional C and Cl/Br isotope fractionations of HOCs on GC using GC-double focus magnetic-sector high resolution mass spectrometry (GC-DFS-HRMS). The two-dimensional C and Cl/Br isotope fractionations of four organochlorines and four bromobenzenes on GC were simultaneously measured by GC-DFS-HRMS. The isotope fractionations were evaluated with isotope ratios, relative variations of isotope ratios (△hE) and isotope fractionation extents (ΛhE). All the HOCs exhibited significant inverse C and Cl/Br isotope fractionations, with Λ13C of 38.14‰-307.56‰, Λ37Cl of 59.60‰-146.85‰, and Λ81Br of 25.89‰-142.10‰. The isotope fractionations were significant in both ends of chromatographic peaks, while the isotope ratios in center retention-time segments were the closest to comprehensive isotope ratios in the whole peaks. Significant correlations between C isotope fractionation and Cl/Br isotope fractionation were observed, indicating that the isotope fractionations might have strong relationships and/or be dominated by similar factors. Relevant mechanisms for the two-dimensional C and Cl/Br isotope fractionations were tentatively proposed on basis of a modified two-film model and the theories related to zero point energy. The results of this study gains new insights into concurrent two-dimensional isotope fractionation behaviors of HOCs during physical processes, and are conducive to CSIA studies involving C, Cl and Br for obtaining high-quality data, particularly to dual-elements CSIA of C and Cl/Br.

    更新日期:2018-07-08
  • Ultrasensitive and label-free electrochemical aptasensor of kanamycin coupling with hybridization chain reaction and strand-displacement amplification
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-06
    Ruijin Zeng, Lingshan Su, Zhongbin Luo, Lijia Zhang, Minghua Lu, Dianping Tang

    This work reports the proof-of-concept of an ultrasensitive label-free electrochemical aptasensor for Kanamycin (Kana) detection coupling strand-displacement amplification (SDA) with hybridization chain reaction (HCR). In the presence of target Kana, the analyte triggers conformational change of hairpin HP1 (HP1) and two-staged SDA to produce short single-stranded DNA (S1) with the aid of KF polymerase and nicking endonuclease. Meanwhile, the as-produced S1 hybridizes with the immobilized hairpin HP2 (HP2) on the electrode to open the hairpin, thereby resulting in the formation of DNA duplex. Thereafter, DNA duplex is selectively digested by Exo III accompanying S1 recycling. The residual single-stranded probe (S2) on the electrode opens another two hairpins in sequence and propagates a chain reaction of hybridization events between two alternating hairpins (H1 and H2) to form a long nicked double-helix. Upon addition of redox-active methylene blue (MB), numerous indicators are intercalated into the grooves of double-helix DNA polymers, each of which produces an electrochemical signal within the applied potentials. Under optimum conditions, the SDA/HCR-based electrochemical aptasensor exhibits a high sensitivity for detection of Kana down to 36 fM with a linear range from 0.05 to 200 pM. Additionally, the as-prepared aptasensor is successfully employed to determinate the Kana in animal derived food (milk). With the advantages of high sensitivity, label-free strategy and excellent selectivity, the developed aptasensor possesses great potential application value in food-safety analysis field.

    更新日期:2018-07-08
  • Flavanols react preferentially with quinones through an electron transfer reaction, stimulating rather than preventing wine browning
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-06
    Lingjun Ma, Andrew L. Waterhouse

    Wine oxidation changes the chemistry, sensory profile and color of wines. In wine oxidation, phenolics are oxidized to quinones and these reactive compounds can be quenched by sacrificial nucleophiles, such as the A-ring on flavanoids, preventing oxidative damage from the loss of desirable flavor molecules. The “catechol” B-ring on flavanoids, in contrast, can be oxidized by quinones through electron transfer reactions that lead to flavanoid quinones, precursors of browning products. Here we compared the rate of flavanoids reacting by either nucleophilic quinone quenching, or by electron transfer to generate flavanoid quinones. Our approach is based on mathematical modeling of reaction data to derive the rate constants of reactions of A-ring quenching vs B-ring electron transfer with caffeic acid quinone, by fitting the predicted loss of precursors and the appearance of products (or derivatives) with experimental data collected by LC/MS. The rate constant of the electron transfer reaction of caffeic acid quinone towards 4-methyl-catechol was fast (k4MC = 3.43E-2 mLmol−1sec−1) but nucleophilic reactions with afzelechin (kAfz = 2.53E-3 mLmol−1sec−1) or malvidin-3-glucoside (kMal = 5.34E-3 mLmol−1sec−1), were much slower. No reaction was detected between caffeic acid quinone and isorhamnetin. Additionally, the electron transfer reaction rate of catechin and caffeic acid quinone was much faster at pH 7 (1.22E-02 mLmol−1sec−1) vs pH 3.5 (1.79E-03 mLmol−1sec−1). These results help explain why the reaction of catechin and caffeic acid quinone favors the formation of browning products, and more so at higher pH values. Furthermore, bisulfite reacted with quinones faster than the electron transfer reactions, preventing the browning observed in the reaction of catechin with caffeic acid quinone in the absence of bisulfite.

    更新日期:2018-07-08
  • Ultrasensitive quantitative detection of small molecules with rapid lateral-flow assay based on high-affinity bifunctional ligand and magnetic nanolabels
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-06
    Sergey L. Znoyko, Alexey V. Orlov, Averyan V. Pushkarev, Elizaveta N. Mochalova, Natalia V. Guteneva, Afanasy V. Lunin, Maxim P. Nikitin, Petr I. Nikitin

    An ultrasensitive lateral-flow assay is developed for rapid quantitative detection of small molecules on-site. The conceptual novelty, which transfers lateral-flow assays to the category of highly sensitive quantitative systems, is due to employment of a bifunctional ligand combined with volumetric registration of magnetic nanolabels. The ligand provides extremely high affinity for trapping the nanolabels and, simultaneously, efficiently competes with the analyzed molecules for the limited quantity of antigen-binding sites on the nanolabels. The developed assay has been demonstrated as the first express method for measuring in human serum of free thyroxine (fT4). The limit of detection is 20 fМ or 16 fg/ml at the assay time < 30 min with the dynamic range of 3 orders. Besides, we present the results of first characterization of kinetic parameters of interaction between free thyroxine and monoclonal antibody, as well as of competitive relationship between fT4 and fT4-biotin. The proposed universal platform can be used for ultrasensitive detection of small molecules in human in vitro diagnostics, veterinary, biosafety and counter-terrorism, food quality control, environmental monitoring, etc., as well as for search of new, previously undetectable, diagnostic markers in medicine.

    更新日期:2018-07-08
  • Curcumin-graphene quantum dots for dual mode sensing platform: electrochemical and fluorescence detection of APO e4, responsible of Alzheimer's disease
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-06
    Abdelmoneim Mars, Maroua Hamami, Linda Bechnak, Digambara Patra, Noureddine Raouafi

    New dual electrochemical and fluorescence sensitive curcumin-graphene quantum dots sensing platform coated on the transparent Indium-Tin-Oxide electrode was developed to sense APO e4 DNA, responsible of Alzheimer's disease. Curcumin molecule with its dual fluorescence and electrochemical properties was electropolymerized on GQDs-ITO surface. EDC/NHS chemistry was used to covalently immobilize an amino-substituted DNA probe via a malonic acid spacer. Quenching of curcumin signals following hybridized DNA complex was employed to quantify APO e4 DNA. Amperometric studies revealed an ultrasensitive behavior toward the formation of DNA complex with a sensitivity of 4.74 nA.mL.pg –1 and a limit of detection as low as 0.48 pg mL –1. The platform exhibits very good performances such as repeatability, reproducibility, selectivity and long storage stability. Fluorescence results were established for the support and the complementarity of electrochemical results. Founded results confirmed the ultrasensitivity of platform with comparable performances. Recorded results in human blood plasma demonstrated the high efficacy of curcumin system sensing even in the clinical matrix.

    更新日期:2018-07-08
  • Aptamer proximity recognition-dependent strand translocation for enzyme-free and amplified fluorescent detection of thrombin via catalytic hairpin assembly
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-06
    Jing Li, Wenjiao Zhou, Ruo Yuan, Yun Xiang

    By coupling a new aptamer proximity recognition-dependent strand translocation strategy with catalytic hairpin assembly (CHA) signal amplification, we have developed a simple and sensitive method for detecting thrombin in human serums. Simultaneous binding of two engineered aptamer probes to the thrombin target significantly increases the local concentrations of the two probes and facilitates the translocation of a ssDNA strand from one of the probes to the other through toehold mediated strand displacement. Such a strand translocation leads to the generation of a ssDNA tail in the aptamer sequence for subsequent initiation of the assembly of two fluorescently quenched hairpins into many DNA duplexes via CHA. The formation of the DNA duplexes thus results in significant fluorescence recovery for amplified detection of thrombin down to 8.3 pM. The developed method is highly selective to the thrombin target against other interference proteins due to the dual recognition mode, and can be employed to monitor thrombin in human serum samples. With the advantage of simplicity, sensitivity and selectivity, this method can be a universal non-enzymatic and nanomaterial-free amplified sensing platform for detecting different protein molecules.

    更新日期:2018-07-08
  • Fabricating carbon-nanotubes-based porous foam for superoxide electrochemical sensing through one-step hydrothermal process induced by phytic acid
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-06
    Xuan Cai, Kaicha Chen, Zhenxing Wang, Wenqian Sun, Hongli Zhao, Huanhuan Zhang, Huilan Chen, Minbo Lan

    The detection of superoxide anions (O2•−) is widely considered as a potential way for cancer diagnosis and the development of enzyme-mimic catalysts is the main challenge in the establishment of electrochemical sensors for O2•− sensing in real samples. Here we present a novel enzyme- and metal-free electrochemical catalyst for superoxide (O2•−) sensing based on the widely-used carbon nanotubes (CNT). Through a one-step hydrothermal process induced by phytic acid (PA), CNT-based porous foam (PACNTF) was successfully obtained. Characterizations demonstrated the enhanced defect and disorder degree of PACNTF after PA treatment, which leaded to the increased active sites of PACNTF for electron transfer and the adhesion of O2•− during the electrochemical process. As a result, the PACNTF presented higher conductivity and larger current response toward O2•− sensing when compared with CNT precursor and CNTF without PA treatment. The sensitivity of PACNTF/SPCE was calculated to be 1230 μA cm-2 mM-1 in the linear range of 0-193.6 μM (R2 = 0.965) and 373 μA cm-2 mM-1 in the linear range of 193.6-1153.6 μM (R2 = 0.995) with a limit of detection of 0.16 μM (S/N = 3). Further, the PACNTF/SPCE presented fast response toward cell-released O2•− stimulated by Zymosan A. The above results indicated that the fabricated sensor holds potential usage in in biological samples.

    更新日期:2018-07-08
  • A highly conductive thin film composite based on silver nanoparticles and malic acid for selective electrochemical sensing of trichloroacetic acid
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-06
    R.M. Bashami, M. Tahir Soomro, Amna N. Khan, Elham S. Aazam, Iqbal M.I. Ismail, M.S. El-Shahawi

    A highly conductive thin film composite based on silver nanoparticles (AgNPs) and malic acid (MA) was deposited on glassy carbon electrode (GCE) for the selective and sensitive electrochemical sensing of trichloroacetic acid (TCA). The casting solution containing MA functionalized AgNPs was employed as a precursor for the thermal deposition of the AgNPs integrated MA thin film composite onto the GCE surface. The uniform coverage of AgNPs within the thin film composite at GCE was obtained by field emission scanning electron microscopy (FESEM). A significantly high charge transfer resistance of the modified electrode (85.7 Ω for AgNPs-MA/GCE in 2 mM [Fe(CN)6]3-/4- at a bias of +0.235 V as compared to bare GCE (38.01 Ω) verified the optimum coating of AgNPs-MA composite at the surface of the electrode. The AgNPs-MA composite deposited GCE revealed substantial electrocatalytic activity toward TCA reduction with significantly enhanced reduction current. The novel electrode manifested a linear square wave voltammetric (SWV) response over the concentration ranges of 0.1-2 (R2 = 0.9953) and 4-100 μM (R2 = 0.9969) with a limit of detection (LOD) and limit of quantification (LOQ) of 30 nM and 92.5 nM, respectively. The modified electrode exhibited an excellent long-term stability (30 days) with the retention of >95% of initial current. The selectivity of the proposed electrode for the determination of TCA was examined in the presence of dichloroacetic acid (DCA) and monochloroacetic acid (MCA) with the retention of high recovery percentages.

    更新日期:2018-07-08
  • Macro-mesoporous organosilica monoliths with bridged-ethylene and terminal-vinyl: high-density click functionalization for chromatographic separation
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-04
    Ci Wu, Yu Liang, Xudong Zhu, Qun Zhao, Fei Fang, Xiaodan Zhang, Zhen Liang, Lihua Zhang, Yukui Zhang

    A novel kind of macro-mesoporous organosilica monolith, with not only bridged-ethylene groups incorporated into the skeleton but also terminal-vinyl groups protruded from the pore-wall, was prepared so that high-loaded double bonds were achieved. Via highly efficient “thiol-ene” click reaction of such high-loaded double bonds, the surface coverage of C18 groups on monolith could be 5.54 μmol m-2, significantly larger than that of the reported separation materials, beneficial to improvement of separation resolution, especially for peptide separation. The separation performance was evaluated using alkylbenzenes and standard peptides. Furthermore, the tryptic digests of complex sample was successfully analyzed. Because of high separation resolution of our prepared hybrid monolith, the peak capacity for 6-h gradient was achieved as 482. Coupling to LTQ Orbitrap Velos Mass Spectrometry, 22523 tryptic peptides from 4423 proteins were identified from the HeLa cells, more than that using the other long-gradient separation by the same system reported, showing great promising of such monolith for large-scale in-depth proteomic analysis.

    更新日期:2018-07-05
  • A novel enzyme-free glucose and H2O2 sensor based on 3D graphene aerogels decorated with Ni3N nanoparticles
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-03
    Duanduan Yin, Xiangjie Bo, Jian Liu, Liping Guo

    In this work, a novel enzyme-free glucose and hydrogen peroxide (H2O2) sensor based on Ni3N nanoparticles on conductive 3D graphene aerogels (Ni3N/GA) has been successfully synthesized by using hydrothermal reaction, freeze-dried and then calcined under NH3 atmosphere. The obtained Ni3N/GA composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption–desorption isotherms and electrochemical methods. The results show the obtained 3D Ni3N/GA composites exhibit excellent electrochemical performance toward glucose oxidation and H2O2 reduction with larger catalytic rate constant Kcat value of 3.75 × 103 M-1 s −1 and 1.24 × 103 M-1 s −1, respectively. As a glucose sensor, the obtained electrode provides a wide detection range of 0.1–7645.3 μM, fast response time within 3 s, high sensitivity of 905.6 μA mM-1 cm-2 and low detection limit of 0.04 μM. For detection of H2O2, this prepared sensor offers a wide detection range (5 μM–75.13 mM), fast response time (within 5 s), sensitivity (101.9 μA mM-1 cm-2) and low detection limit (1.80 μM). This enzyme-free glucose and H2O2 sensor display satisfactory selectivity, reproducibility and long-term storage stability. Additionally, the sensor can also be used for glucose and H2O2 detection in human blood serum. The results demonstrate that 3D GA nanostructures provide an enviable conductive network for efficient charge transfer and avoid Ni3N nanoparticles aggregation, which is advantageous for electrocatalytic applications.

    更新日期:2018-07-04
  • Determination of volatile fatty acids in digestate by solvent extraction with dimethyl carbonate and gas chromatography-mass spectrometry
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-03
    Michele Ghidotti, Daniele Fabbri, Cristian Torri, Sergio Piccinini

    Volatile fatty acids (VFAs) are among the most important parameters in process monitoring of anaerobic digestion plants for biogas production. The concentration of single VFA species is typically determined by direct injection of the acidified aqueous phase of digestate samples into GC-FID. Analysis of dimethyl carbonate extracts was investigated as an alternative method consisting of a simple and rapid in-vial procedure of acidification and solvent extraction of the sample, followed by centrifugation and GC-MS analysis. The principal figures of merit resulting from internal standard calibration were comparable to those proposed for the direct analysis of aqueous digestate, while the analysis of real samples did not provide statistically significant differences between the two methods according to parametric and non-parametric tests. Procedural aspects including sample amount and solid removal improved with dimethyl carbonate, while GC contamination was reduced. The method was applied to seventeen samples from fully operating anaerobic digesters fed with various feedstocks and enabled the individuation of high probability of system stress through the values of total VFA, propanoic acid, longer chained VFA concentrations and the ratio between acetic and propanoic acid concentrations. The use of dimethyl carbonate allowed the detection of alicyclic and aromatic acids that could represent new molecular markers in assessing the origin of feed and process conditions.

    更新日期:2018-07-04
  • Ultra-performance supercritical fluid chromatography: a powerful tool for the enantioseparation of thermotropic fluorinated liquid crystals
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-03
    Petra Vaňkátová, Květa Kalíková, Anna Kubíčková

    A fast and simple supercritical fluid chromatography method for the enantioseparation of twenty newly synthesized orthoconic antiferroelectric liquid crystals is reported for the first time. The effects of alkoxy spacer length and fluorine atom presence and position in the phenyl ring on chromatographic behavior were investigated. Baseline enantioseparation of all compounds was achieved using simple mobile phases consisting of carbon dioxide and alcohol as cosolvent on (3,5-dimethylphenylcarbamate) derivative of amylose as chiral stationary phase. The analysis times ranged from 2 to 4 and from 4 to 7 min for most samples when using methanol and propane-2-ol, respectively. The significant effect of cosolvent type on the enantioseparation of these compounds was assessed and partial complementarity of methanol and propane-2-ol was observed.

    更新日期:2018-07-04
  • A novel malic acid-enhanced method for the analysis of 5-methyl-2′-deoxycytidine, 5-hydroxymethyl-2′-deoxycytidine, 5-methylcytidine and 5-hydroxymethylcytidine in human urine using hydrophilic interaction liquid chromatography-tandem mass spectrometry
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-03
    Cheng Guo, Cong Xie, Qin Chen, Xiaoji Cao, Mengzhe Guo, Shu Zheng, Yinsheng Wang

    5-Methyl-2′-deoxycytidine (5-mdC), 5-hydroxymethyl-2′-deoxycytidine (5-hmdC), 5-methylcytidine (5-mrC) and 5-hydroxymethylcytidine (5-hmrC) are epigenetic marks of DNA and RNA, and aberrant levels of these modified nucleosides were found to be associated with various cancers. Urine is a preferred source of biological fluid for biomarker discovery because the sample collection process is not invasive to patients. Herein, we developed a novel malic acid-enhanced hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method for sensitive and simultaneous quantification of the modified cytosine nucleosides in human urine. Malic acid markedly increased the detection sensitivities of all four cytosine nucleosides, with the limits of detection (LODs) for 5-mdC, 5-hmdC, 5-mrC and 5-hmrC being 0.025, 0.025, 0.025 and 0.050 fmol, respectively. By using this method, we demonstrated, for the first time, the presence of 5-hmrC in human urine, and we successfully quantified 5-mdC, 5-hmdC, 5-mrC and 5-hmrC in urine samples collected from 90 patients with colorectal cancer (CRC) and 90 healthy controls. We found that the levels of 5-mdC, 5-hmdC, 5-mrC and 5-hmrC in urine were all substantially decreased in CRC patients, suggesting that these modified nucleosides might have great potential to be noninvasive biomarkers for early detection and prognosis of CRC. Together, we established a novel and sensitive method for detecting 5-methylated and 5-hydroxymethylated cytosine nucleosides in human urine and the results from this study may stimulate future investigations about the regulatory roles of these cytosine derivatives in the initiation and development of CRC.

    更新日期:2018-07-04
  • A rapid LC-MS method for qualitative and quantitative profiling of plant apocarotenoids
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-03
    Jianing Mi, Kun-Peng Jia, Jian You Wang, Salim Al-Babili

    Carotenoid cleavage products (apocarotenoids; APOs) exert important biological functions in light perception and as vitamin A source, signaling molecules, hormone precursors, pigments and volatiles. However, an analytical method that allows simultaneous profiling of these diverse compounds is still missing. We developed an efficient method to analyze APOs present in plant tissues, which is based on ultra-high performance liquid chromatographic separation and high-resolution hybrid quadrupole-Orbitrap (Q-Orbitrap) mass spectrometry (MS). Our approach allowed unambiguous identification and quantification of volatile and non-volatile APOs in a single run. Modified sample preparation and optimized ultra-high performance liquid chromatography (UHPLC)-MS parameters permitted the measurement of APOs in Oryza sativa seedlings and Spinacia oleracea leaves, unraveling 20 endogenous APOs with chain lengths ranging from C10 to C30, confirmed by high-resolution MS, MS/MS data and using synthetic standards. Our experimentation demonstrates that the usage of methanol with 0.1% butylated hydroxytoluene facilitates the extraction of both short-chain and long-chain APOs from plant materials. In addition, our validated analytical method allows the quantitative analysis of APOs with a wide content range from 2.5 pg/mg to 10 ng/mg dried weight. The adoption of the analytical protocol, as described in this study, realizes the measurement of volatile APOs by using a LC-MS method, hence, allowing informative and reliable profiling of APOs, which is important for determining the content of these compounds in food and crucial for understanding their function and metabolism in plants.

    更新日期:2018-07-04
  • Electrochemical recognition of nitrophenol isomers by assembly of pillar[5]arenes mutifilms
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-03
    Xiaoping Tan, Genfu Zhao, Xu Zhou, Taohong Li, Hong Lei, Guanben Du, Long Yang

    The rational design of electrochemical methods for isomer recognition is a focus of research in the molecular recognition and separation fields. In this work, a novel, rapid, and convenient electrochemical approach for recognition of nitrophenol isomers was constructed based on the alternating layer-by-layer (LbL) assembly of water-soluble cationic and anionic pillar [5]arene on a carboxylic graphene (C-Gra) modified glass carbon electrode. The electrochemical recognition of nitrophenol isomers was investigated by differential pulse voltammetry (DPV). The electrochemical results reveal that both the peak currents of m-nitrophenol (m-NP) and p-nitrophenol (p-NP) increased with the increasing of the layer number of the assembled pillar [5]arene, whereas the peak current of o-nitrophenol (o-NP) decreased with the increased layers, which demonstrated an efficient route for discriminating the nitrophenol isomers. The molecular recognition mechanism was studied by 1H NMR spectra, which indicated that the m-NP and p-NP can be included in the cavity of the pillar [5]arene host. However, the o-NP could not enter into the host of pillar [5]arene, which was ascribed to the formation of intramolecular hydrogen bond of o-NP. The LbL assembly modified GCE was used for detecting p-NP and m-NP. A low detection limit of 0.33 μM (S/N=3) and a linear response range of 1–90 μM for p-NP were obtained by using this method. And the detection limit of 0.16 μM (S/N=3) and a linear response range of 0.5–70 μM for m-NP were obtained. This method of LbL assembly modified GCE has potential application in molecular recognition and separation.

    更新日期:2018-07-04
  • A gold nanoparticle-based lateral flow biosensor for sensitive visual detection of the potato late blight pathogen, Phytophthora infestans
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-07-03
    Fangfang Zhan, Tian Wang, Linda Iradukunda, Jiasui Zhan

    Phytophthora infestans, the causal agent of late blight in potatoes and tomatoes, is the most important and ongoing pathogenic threat to agricultural production worldwide. Rapid and early identification of P. infestans is an essential prerequisite for countering the further spread of infection. In this study, a novel method for visual detection of P. infestans has been developed by integrating universal primer mediated asymmetric PCR with gold nanoparticle (AuNP)-based lateral flow biosensor. We employed asymmetric PCR to generate large amounts of single-stranded DNA (ssDNA) by amplifying a region of P. infestans-specific repetitive DNA sequence. The ssDNA products were then applied to the lateral flow biosensor to perform a visual detection using sandwich-type hybridization assays. In the presence of target DNA, sandwich-type hybridization reactions among the AuNP–probe, target DNA and capture probe were performed on the test line of the biosensor, and then a characteristic red band was produced for the accumulation of AuNPs. Quantitative analysis obtained by recording the optical intensity of the red band demonstrated that this biosensor could detect as little as 0.1 pg μL-1 genomic DNA. Furthermore, the specificity of the biosensor was confirmed by detecting three other Phytophthora species and two pathogenic fungi. We believe this method has potential application in early prediction of potato late blight disease and instigation of management actions to reduce the risk of epidemic development.

    更新日期:2018-07-04
  • 更新日期:2018-07-02
  • Cu(Ⅱ) triggering redox-regulated anti-aggregation of gold nanoparticles for ultrasensitive visual sensing of iodide
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-30
    Ruifeng Peng, Haibo He, Qian Wang, Xiaoxia Yan, Qiongwei Yu, Haixiao Qin, Yunyi Lei, Liqiang Luo, Yuqi Feng
    更新日期:2018-07-01
  • Enhanced catalytic capability of electroactive biofilm modified with different kinds of carbon nanotubes
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-30
    Zhaohong Jiang, Di Zhang, Lei Zhou, Dandan Deng, Min Duan, Ying Liu
    更新日期:2018-07-01
  • 更新日期:2018-07-01
  • 更新日期:2018-07-01
  • Phosphorus-doped graphene-based electrochemical sensor for sensitive detection of acetaminophen
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-30
    Xuan Zhang, Kai-Ping Wang, Li-Na Zhang, Yi-Chi Zhang, Li Shen
    更新日期:2018-07-01
  • Past-in-the-Future. Peak detection improves targeted mass spectrometry imaging
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-28
    Francesca Falcetta, Lavinia Morosi, Paolo Ubezio, Silvia Giordano, Alessandra Decio, Raffaella Giavazzi, Roberta Frapolli, Mridula Prasad, Pietro Franceschi, Maurizio D'Incalci, Enrico Davoli
    更新日期:2018-06-30
  • 更新日期:2018-06-30
  • SPE–LC-MS investigations for the isolation and fractionation of acidic oil degradation products
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-29
    Dieter Schemeth, Nikoline Juul Nielsen, Jan H. Christensen
    更新日期:2018-06-30
  • Kinetic study of continuous liquid-liquid extraction of wine with real-time detection
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-29
    Hui-Hsien Yang, Ewelina P. Dutkiewicz, Pawel L. Urban
    更新日期:2018-06-30
  • 更新日期:2018-06-28
  • Comparison of different speciation techniques to measure Zn availability in hydroponic media
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-27
    Encarna Companys, Josep Galceran, Jaume Puy, Maria Sedó, Ruben Vera, Enriqueta Anticó, Clàudia Fontàs
    更新日期:2018-06-28
  • 更新日期:2018-06-28
  • 更新日期:2018-06-27
  • Infrared laser ablation sampling coupled with data independent high resolution UPLC-IM-MS/MS for tissue analysis
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-26
    Michael E. Pettit, Fabrizio Donnarumma, Kermit K. Murray, Touradj Solouki
    更新日期:2018-06-27
  • A validated multi-matrix platform for metabolomic fingerprinting of human urine, feces and plasma using ultra-high performance liquid-chromatography coupled to hybrid orbitrap high-resolution mass spectrometry
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-26
    Ellen De Paepe, Lieven Van Meulebroek, Caroline Rombouts, Steve Huysman, Kaat Verplanken, Bruno Lapauw, Jella Wauters, Lieselot Y. Hemeryck, Lynn Vanhaecke
    更新日期:2018-06-27
  • A cotton thread fluidic device with a wall-jet pencil-drawn paper based dual electrode detector
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-26
    Nicolò Dossi, Rosanna Toniolo, Fabio Terzi, Nicola Sdrigotti, Franco Tubaro, Gino Bontempelli
    更新日期:2018-06-27
  • 更新日期:2018-06-27
  • Characterization of ion exchange functionalized cyclic olefin polymer open tubular columns
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-26
    Weixiong Huang, Sasikarn Seetasang, Purnendu K. Dasgupta
    更新日期:2018-06-27
  • Harnessing the affinity of magnetic nanoparticles toward dye-labeled DNA and developing it as an universal aptasensor revealed by lipopolysaccharide detection
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-26
    Long Ma, Nana Sun, Yuanyuan Meng, Chunhao Tu, Xiuqi Cao, Yongchang Wei, Liqiang Chu, Aipo Diao
    更新日期:2018-06-27
  • Electro-addressable conductive alginate hydrogel for bacterial trapping and general toxicity determination
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-26
    N. Vigués, F. Pujol-Vila, A. Marquez-Maqueda, X. Muñoz-Berbel, J. Mas
    更新日期:2018-06-27
  • Recent advances in microfluidic technology for manipulation and analysis of biological cells (2007–2017)
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-26
    Md Kowsar Alam, Koomson Emmanuel, Zou Heng, Yi Changqing, Li Cheuk-Wing, Xu Tao, Yang Mengsu
    更新日期:2018-06-27
  • 更新日期:2018-06-25
  • A novel one- and two-photon fluorescent probe induced by light for selective imaging of Cys in living cells and tissues
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-22
    Yuxiang Ma, Ying Zhao, Lili Xia, Jinxin Huang, Yueqing Gu, Peng Wang
    更新日期:2018-06-22
  • 更新日期:2018-06-22
  • Optimization of extraction methods for comprehensive profiling of perfluoroalkyl and polyfluoroalkyl substances in firefighting foam impacted soils
    Anal. Chim. Acta (IF 5.123) Pub Date : 2018-06-20
    Gabriel Munoz, Prisca Ray, Sandra Mejia-Avendaño, Sung Vo Duy, Dat Tien Do, Jinxia Liu, Sébastien Sauvé
    更新日期:2018-06-22
  • 更新日期:2018-06-22
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
化学 • 材料 期刊列表