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  • Lipid metabolism in mouse embryonic fibroblast cells in response to autophagy induced by nutrient stress
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Sensen Shen, Li Yang, Linnan Li, Yu Bai, Huwei Liu

    Autophagy is of great significance in maintaining cellular homeostasis. Aberrant autophagy has been reported to contribute to the disease aetiology of metabolic syndrome, especially several key lysosomal storage disorders. However, the molecular mechanisms and the correlation between autophagy and lipid metabolism remains unclear. This study was designed and aimed to reveal the alteration of lipid metabolism in response to the autophagy induced by nutrient stress to give new insights into the molecular mechanisms between autophagy and lipid metabolism. An online normal-phase/reversed-phase two-dimensional liquid chromatography-mass spectrometry (NP/RP 2D LC-MS) method was developed to perform the lipidomics analysis of Atg7−/− mouse embryonic fibroblast cells (MEFs) and wild-type MEFs under nutrient stress. 48 and 35 lipid species in wild-type and Atg7−/− MEFs respectively finally meet the screening criteria with p-value less than 0.05 and fold change more than 1.5 in response to nutrient stress. Their alterations indicated that autophagy participated lipid metabolism to generate energy and form autophagosomes with significantly increased free fatty acids and glycerophospholipids, which protected wild-type MEFs from serious damages and delayed cell death. However, in Atg7−/− MEFs, due to the inhibition of autophagy, lipids were continuously consumed and cells suffered from damages even death. These results illustrated the close relationship between autophagy and lipid metabolism comprehensively and revealed diverse lipid targets for the investigation of autophagy.

    更新日期:2017-11-15
  • Development of an LC-ESI(-)-MS/MS method for the simultaneous quantification of 35 isoprostanes and isofurans derived from the major n3- and n6-PUFAs
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Katharina M. Rund, Annika I. Ostermann, Laura Kutzner, Jean-Marie Galano, Camille Oger, Claire Vigor, Sabine Wecklein, Nina Seiwert, Thierry Durand, Nils Helge Schebb

    Misregulation of oxidative and antioxidative processes in the organism – oxidative stress – contributes to the pathogenesis of different diseases, e.g. inflammatory or neurodegenerative diseases. Oxidative stress leads to autoxidation of polyunsaturated fatty acids giving rise to prostaglandin-like isoprostanes (IsoP) and isofurans (IsoF). On the one hand they could serve as biomarker of oxidative stress and on the other hand may act as lipid mediators, similarly as the enzymatically formed oxylipins. In the present paper we describe the development of an LC-ESI(-)-MS/MS method allowing the parallel quantification of 27 IsoP and 8 IsoF derived from 6 different PUFA (ALA, AA, EPA, AdA, DPA, DHA) within 12 min. The chromatographic separation was carried out on a RP-C18 column (2.1 × 150 mm, 1.8 μm) yielding narrow peaks with an average width at half maximum of 3.3–4.2 s. Detection was carried out on a triple quadrupole mass spectrometer operating in selected reaction monitoring mode allowing the selective detection of regioisomers. The limit of detection ranged between 0.1 and 1 nM allowing in combination to solid phase extraction the detection of IsoP and IsoF at subnanomolar concentration in biological samples. The method was validated for human plasma showing high accuracy and precision. Application of the approach on the investigation of oxidative stress in cultured cells indicated a distinct pattern of IsoP and IsoF in response to reactive oxygen species which warrants further investigation.The described method is not only the most comprehensive approach for the simultaneous quantification of IsoP and IsoF, but it was also integrated in a targeted metabolomics method (Ostermann et al. (2015) Anal Bioanal Chem) allowing the quantification of in total 164 oxylipins formed enzymatically and non-enzymatically within 30.5 min.

    更新日期:2017-11-15
  • Development of a GC/MS method for the qualitative and quantitative analysis of mixtures of free fatty acids and metal soaps in paint samples
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Jacopo La Nasa, Francesca Modugno, Matteo Aloisi, Anna Lluveras Tenorio, Ilaria Bonaduce

    In this paper we present a new analytical GC/MS method for the analysis of mixtures of free fatty acids and metal soaps in paint samples. This approach is based on the use of two different silylating agents: N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and 1,1,1,3,3,3-hexamethyldisilazane (HMDS).Our experimentation demonstrated that HMDS does not silylate fatty acid carboxylates, so it can be used for the selective derivatization and GC/MS quantitative analysis of free fatty acids. On the other hand BSTFA is able to silylate both free fatty acids and fatty acids carboxylates. The reaction conditions for the derivatization of carboxylates with BSTFA were thus optimized with a full factorial 32 experimental design using lead stearate and lead palmitate as model systems. The analytical method was validated following the ICH guidelines. The method allows the qualitative and quantitative analysis of fatty acid carboxylates of sodium, calcium, magnesium, aluminium, manganese, cobalt, copper, zinc, cadmium, and lead and of lead azelate. In order to exploit the performances of the new analytical method, samples collected from two reference paint layers, from a gilded 16th century marble sculpture, and from a paint tube belonging to the atelier of Edvard Munch, used in the last period of his life (1916–1944), were characterized.

    更新日期:2017-11-14
  • Applying quantitative metabolomics based on chemical isotope labeling LC-MS for detecting potential milk adulterant in human milk
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Dorothea Mung, Liang Li

    There is an increasing demand for donor human milk to feed infants for various reasons including that a mother may be unable to provide sufficient amounts of milk for their child or the milk is considered unsafe for the baby. Selling and buying human milk via the Internet has gained popularity. However, there is a risk of human milk sold containing other adulterants such as animal or plant milk. Analytical tools for rapid detection of adulterants in human milk are needed. We report a quantitative metabolomics method for detecting potential milk adulterants (soy, almond, cow, goat milk and infant formula) in human milk. It is based on the use of a high-performance chemical isotope labeling (CIL) LC-MS platform to profile the metabolome of an unknown milk sample, followed by multivariate or univariate comparison of the resultant metabolomic profile with that of human milk to determine the differences. Using dansylation LC-MS to profile the amine/phenol submetabolome, we could detect an average of 4129 ± 297 (n = 9) soy metabolites, 3080 ± 470 (n = 9) almond metabolites, 4256 ± 136 (n = 18) cow metabolites, 4318 ± 198 (n = 9) goat metabolites, 4444 ± 563 (n = 9) infant formula metabolites, and 4020 ± 375 (n = 30) human metabolites. This high level of coverage allowed us to readily differentiate the six different types of samples. From the analysis of binary mixtures of human milk containing 5, 10, 25, 50 and 75% other type of milk, we demonstrated that this method could be used to detect the presence of as low as 5% adulterant in human milk. We envisage that this method could be applied to detect contaminant or adulterant in other types of food or drinks.

    更新日期:2017-11-14
  • Homochiral porous organic cage used as stationary phase for open tubular capillary electrochromatography
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Jun-Hui Zhang, Peng-Jing Zhu, Sheng-Ming Xie, Min Zi, Li-Ming Yuan

    Porous organic molecular cages, as a new type of porous materials, have in recent years attracted a tremendous amount of attention for their potential applications. However, to the best of our knowledge, there has been no attempt to utilize porous organic molecular cages as stationary phases in capillary electrochromatography (CEC). We report herein the use of a homochiral porous organic cage (POC) (CC3-R) as a stationary phase in open tubular capillary electrochromatography (OT-CEC) for the separation of chiral compounds and positional isomers. The column was fabricated using CC3-R as the stationary phase by a static coating method. Separation of furoin, benzoin, and alprenlol were achieved on the CC3-R coated column, with the highest resolution value (Rs = 3.35) for the separation of benzoin. The influences of pH and buffer concentration on separation have been investigated. Besides, the CC3-R column also exhibited good selectivity for the separation of positional isomers, including those of nitrophenols, phenylenediamines, aminophenols, and ionones. The run-to-run (n = 5), day-to-day (n = 5), column-to-column (n = 3), and batch-to-batch (n = 3) relative standard deviations (RSDs) for the analyte migration time were in the range of 0.5–1.5%, 0.2–1.8%, 1.2–2.1% and 1.5–2.8%, respectively. The RSDs for the migration time and enantioselectivity of the analyte were less than 5.9% and 2.2% (inter-day, n = 5) after a week of continuous use. This work also indicates that porous organic molecular materials are promising for enantioseparation in CEC and look set to become more attractive in separation science.

    更新日期:2017-11-14
  • Effects of structure on the performance of latex nanoparticles as a pseudostationary phase in electrokinetic chromatography
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Jesse S. Hyslop, Julie R. McGettrick, Leah M.G. Hall, Hungngai Chuk, Christopher P. Palmer

    The fundamental relationships between the structure and chemistry of latex nanoparticles synthesized by reversible addition fragmentation chain transfer (RAFT) controlled living polymerization and their subsequent performance as pseudostationary phases (PSP) is reported in this paper. RAFT enables the rational optimization of latex nanoparticle pseudostationary phases and control of the behavior of the PSP. Nanoparticles comprised of amphiphilic diblock copolymers of 2-acrylamido-2-methylpropane sulfonic acid-derived ionic/hydrophilic blocks and butyl- ethyl- or methyl-acrylate-derived hydrophobic blocks were synthesized in two sizes. The mobility, methylene selectivity, and efficiency of each of the six pseudostationary phases are reported, as well as the relationship between monomer quantity and NP size. Linear solvation energy relationships are reported and compared to SDS micelles and previous nanoparticle pseudostationary phases. The solvation characteristics and selectivity of nanoparticle pseudostationary phases is shown to be affected primarily by the structure of the hydrophobic copolymer block. Butyl acrylate nanoparticles 17 nm in diameter are found to provide the best overall separation performance with over 500 thousand theoretical plates generated in 6 min separations.

    更新日期:2017-11-14
  • Quantification ethyl carbamate in wines using reaction-assisted-extraction with 9-xanthydrol and detection by heart-cutting multidimensional gas chromatography-mass spectrometry
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Qiqi Tu, Wanshu Qi, Junbo Zhao, Li Zhang, Yinlong Guo

    9-Xanthydrol was introduced as an assisted-extraction-reagent to quantify ethyl carbamate (EC) in wines by heart-cutting multidimensional gas chromatography coupled with mass spectrometry (MDGC-MS). 9-Xanthydrol could help to increase the extraction efficiency, because it could react with ethyl carbamate to form the low-polar product, which facilitated the transfer of ethyl carbamate into organic phase. Then the reaction product was decomposed in high temperature, so ethyl carbamate could be obtained again in injector port. Heart-cutting multidimensional gas chromatography coupled with mass spectrometry was used not only for avoiding 9-xanthydrol interference but also for getting a larger volume injector, higher sensitivity and lower limit of detection. The method was optimized and validated in terms of sample volume, sodium chloride, the acid concentration, the 9-xanthydrol concentration and the reaction time. Good linear relationship (R2 = 0.9998) over the concentration range of 2.00 μg L−1 - 200.00 μg L−1 was obtained. The limit of detection (LOD, 0.02 μg L−1) and quantification (LOQ, 0.10 μg L−1) were lower than previously reported. The RSDs of precision (repeatability and reproducibility) were lower than 8.15%, and the recovery (96.17–99.25%) and accuracy (99.21–110.93%) were validated as well. This methodology was applied to the quantification of ethyl carbamate in several different fermented wines with values ranging from 13.05 to 155.20 μg L−1.

    更新日期:2017-11-14
  • Carbon fiber brush electrode as a novel substrate for atmospheric solids analysis probe (ASAP) mass spectrometry: Electrochemical oxidation of brominated phenols
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Jana Skopalová, Petr Barták, Petr Bednář, Hana Tomková, Tomáš Ingr, Iveta Lorencová, Pavla Kučerová, Roman Papoušek, Lucie Borovcová, Karel Lemr

    A carbon fiber brush electrode (CFBE) was newly designed and used as a substrate for both controlled potential electrolysis and atmospheric solids analysis probe (ASAP) mass spectrometry. Electropolymerized and strongly adsorbed products of electrolysis were directly desorbed and ionized from the electrode surface. Electrochemical properties of the electrode investigated by cyclic voltammetry revealed large electroactive surface area (23 ± 3 cm2) at 1.3 cm long array of carbon fibers with diameter 6–9 μm. Some products of electrochemical oxidation of pentabromophenol and 2,4,6-tribromophenol formed a compact layer on the carbon fibers and were analyzed using ASAP. Eleven new oligomeric products were identified including quinones and biphenoquinones. These compounds were not observed previously in electrolyzed solutions by liquid or gas chromatography/mass spectrometry. The thickness around 58 nm and 45 nm of the oxidation products layers deposited on carbon fibers during electrolysis of pentabromophenol and 2,4,6-tribromophenol, respectively, was estimated from atomic force microscopy analysis and confirmed by scanning electron microscopy with energy-dispersive X-ray spectroscopy measurements.

    更新日期:2017-11-14
  • Optimization of mass spectrometric parameters improve the identification performance of capillary zone electrophoresis for single-shot bottom-up proteomics analysis
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-14
    Zhenbin Zhang, Norman J. Dovichi

    The effects of MS1 injection time, MS2 injection time, dynamic exclusion time, intensity threshold, and isolation width were investigated on the numbers of peptide and protein identifications for single-shot bottom-up proteomics analysis using CZE-MS/MS analysis of a Xenopus laevis tryptic digest. An electrokinetically pumped nanospray interface was used to couple a linear-polyacrylamide coated capillary to a Q Exactive HF mass spectrometer. A sensitive method that used a 1.4 Th isolation width, 60,000 MS2 resolution, 110 ms MS2 injection time, and a top 7 fragmentation produced the largest number of identifications when the CZE loading amount was less than 100 ng. A programmable autogain control method (pAGC) that used a 1.4 Th isolation width, 15,000 MS2 resolution, 110 ms MS2 injection time, and top 10 fragmentation produced the largest number of identifications for CZE loading amounts greater than 100 ng; 7218 unique peptides and 1653 protein groups were identified from 200 ng by using the pAGC method. The effect of mass spectrometer conditions on the performance of UPLC-MS/MS was also investigated. A fast method that used a 1.4 Th isolation width, 30,000 MS2 resolution, 45 ms MS2 injection time, and top 12 fragmentation produced the largest number of identifications for 200 ng UPLC loading amount (6025 unique peptides and 1501 protein groups). This is the first report where the identification number for CZE surpasses that of the UPLC at the 200 ng loading level. However, more peptides (11476) and protein groups (2378) were identified by using UPLC-MS/MS when the sample loading amount was increased to 2 μg with the fast method. To exploit the fast scan speed of the Q-Exactive HF mass spectrometer, higher sample loading amounts are required for single-shot bottom-up proteomics analysis using CZE-MS/MS.

    更新日期:2017-11-14
  • A high sensitive and contaminant tolerant matrix for facile detection of membrane proteins by matrix-assisted laser desorption/ionization mass spectrometry
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-13
    Sheng Wang, Chunsheng Xiao, Liyan Jiang, Ling Ling, Xuesi Chen, Xinhua Guo

    Despite the significance of membrane proteins (MPs) in biological system is indisputable, their specific natures make them notoriously difficult to be analyzed. Particularly, the widely used Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) prefers analyses of hydrophilic cytosolic proteins and has a limited ionization efficiency towards hydrophobic MPs. Herein, a hydrophobic compound (E)-propyl α-Cyano-4-Hydroxyl Cinnamylate (CHCA-C3), a propyl-esterified derivative of α-cyano-4-hydroxycinnamic acid (CHCA), was applied as a contaminant tolerant matrix for high sensitivity MALDI-MS analyses of MPs. With CHCA-C3, the detection limits of hydrophobic peptides were 10- to 100-fold better than those using CHCA. Furthermore, high quality of spectra could be achieved in the presence of high concentration of chaotropes, salts and detergents, as well as human urinary and serum environment. Also, CHCA-C3 could generate uniform sample distribution even in the presence of contaminants. This high contaminant-resistance was revealed to be ascribed to the enhanced hydrophobicity of CHCA-C3 with a lower affinity towards hydrophilic contaminants. The application of CHCA-C3 is further demonstrated by the analysis of trypsin/CNBr digests of bacteriorhodopsin containing seven transmembrane domains (TMDs), which dramatically increased numbers of identified hydrophobic peptides in TMDs and sequence coverage (∼100%). Besides, a combined method by using CHCA-C3 with fluoride solvent and a patterned paraffin plate was established for analysis of integral MPs. We achieved a low detection limit of 10 fmol for integral bacteriorhodopsin, which could not be detected using traditional matrices such as 3,5-dimethoxy-4-hydroxycinamic acid, 2,5-dihydroxyacetophenone even at sample concentration of 10 pmol.

    更新日期:2017-11-14
  • Highly sensitive MicroRNA 146a detection using a gold nanoparticle–based CTG repeat probing system and isothermal amplification
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-13
    Binh Huy Le, Young Jun Seo

    We have developed a gold nanoparticle (AuNP)–based CTG repeat probing system displaying high quenching capability and combined it with isothermal amplification for the detection of miRNA 146a. This method of using a AuNP-based CTG repeat probing system with isothermal amplification allowed the highly sensitive (14 aM) and selective detection of miRNA 146a. A AuNP-based CTG repeat probing system having a hairpin structure and a dTF fluorophore exhibited highly efficient quenching because the CTG repeat–based stable hairpin structure imposed a close distance between the AuNP and the dTF residue. A small amount of miRNA 146a induced multiple copies of the CAG repeat sequence during rolling circle amplification; the AuNP-based CTG repeat probing system then bound to the complementary multiple-copy CAG repeat sequence, thereby inducing a structural change from a hairpin to a linear structure with amplified fluorescence. This AuNP-based CTG probing system combined with isothermal amplification could also discriminate target miRNA 146a from one- and two-base-mismatched miRNAs (ORN 1 and ORN 2, respectively). This simple AuNP-based CTG probing system, combined with isothermal amplification to induce a highly sensitive change in fluorescence, allows the detection of miRNA 146a with high sensitivity (14 aM) and selectivity.

    更新日期:2017-11-14
  • Enzyme-assisted polymer film degradation-enabled biomolecule sensing with poly (N-isopropylacrylamide)-based optical devices
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-11
    Wei Zhang, Menglian Wei, Wildemar S.P. Carvalho, Michael J. Serpe

    A biosensor for mouse Immunoglobulin G (IgG) was generated from responsive polymer-based interference filters (etalons). To accomplish this, an excess amount of alkaline phosphatase-modified goat anti-mouse IgG (AP-GAM, F(ab’)2 fragment specific to mouse IgG) was added to mouse IgG, and allowed to react for some time. After a given reaction time, the bound AP-GAM could be isolated from the unbound, excess AP-GAM by addition of goat anti-mouse IgG (Fc fragment specific)-modified magnetic microspheres (GAM-M) that bind the mouse IgG bound to AP-GAM. After application of a magnetic field, the free, unbound AP-GAM was isolated from the mixture and exposed to an etalon that has its upper Au surface modified with phosphate-containing polymer that can be degraded by AP-GAM. By the phosphate-containing polymer being degraded by the excess AP-GAM, the cleaved phosphate groups can diffuse into the interference filter's active polymer layer that yields a change in the optical properties that can be related to the amount of IgG in the sample. This concept is extremely straightforward to implement, and can be modified to detect a variety of other analytes of interest.

    更新日期:2017-11-11
  • Review on microfluidic paper-based analytical devices towards commercialisation
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-11
    Tugce Akyazi, L. Basabe-Desmonts, Fernando Benito-Lopez

    Paper-based analytical devices introduce an innovative platform technology for fluid handling and analysis, with wide range of applications, promoting low cost, ease of fabrication/operation and equipment independence. This review gives a general overview on the fabrication techniques reported to date, revealing and discussing their weak points as well as the newest approaches in order to overtake current mass production limitations and therefore commercialisation. Moreover, this review aims especially to highlight novel technologies appearing in literature for the effective handling and controlling of fluids. The lack of flow control is the main problem of paper-based analytical devices, which generates obstacles for marketing and slows down the transition of paper devices from the laboratory into the consumers' hands.

    更新日期:2017-11-11
  • Potential of saliva steroid profiling for the detection of endogenous steroid abuse: Reference thresholds for oral fluid steroid concentrations and ratios
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-11
    Michael Polet, Laurie De Wilde, Pieter Van Renterghem, Wim Van Gansbeke, Peter Van Eenoo

    Urine and blood samples are the primary matrices for the detection of exogenous substances in doping control and toxicology. Although these matrices are, in general, very suitable for a wide range of substances, they do show some issues in particular cases. Here, alternative matrices may provide an answer. In this work, a quantitative method for steroid profiling (5 endogenous steroids and their ratios) in oral fluid was developed and validated. In total, 826 saliva samples were analyzed, and inter-individual reference population thresholds for saliva steroid profile parameters were set up. Alterations of this steroid profile after administration of naturally occurring anabolic androgenic steroids (e.g. testosterone (T) or dehydroepiandrosterone (DHEA)) were investigated. In addition, intra-individual short and long-term natural fluctuations were investigated. For longitudinal monitoring in oral fluid, steroid profile ratios (e.g., T/DHEA) were superior to absolute concentrations due to lower susceptibility towards the diurnal pattern. For the detection of a transdermal application of T, the salivary parameter T/DHEA proved to have the highest sensitivity. In contrast with the current screening procedures in urine, there is no need for an additional expensive and time-consuming isotope ratio mass spectrometry confirmation procedure to unequivocally attribute the elevated parameter to an exogenous origin.

    更新日期:2017-11-11
  • Using magnetic beads and signal amplifiers to produce short and simple immunoassays: Application to MMP-9 detection in plasma samples
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-10
    Manel Ben Ismail, Erica de la Serna, Gisela Ruiz-Vega, Teresa García-Berrocoso, Joan Montaner, Mohammed Zourob, Ali Othmane, Eva Baldrich

    Magnetic beads (MB) and signal amplifiers, such as horseradish peroxidase polymers (poly-HRP), have been used before for the production of highly sensitive immunoassays. However, most of the examples reported previously entailed long and tedious multi-step procedures, which were not necessarily shorter or simpler than classical paths such as Enzyme-Linked Immunosorbent Assay (ELISA). Here, instead of exploiting the combination of MB and poly-HRP to ameliorate sensitivity, we show that they conform a powerful tool that can be used to shorten the incubation times, which allows optimizing extremely simple, fast and efficient immunoassays with minimal technical requirements. In order to do so, here we used the highly sensitive and specific pair of antibodies of a commercial ELISA kit to optimize a magneto-ELISA for the detection of matrix metallopeptidase 9 (MMP-9). Three signal amplifiers were then tested and the best performing one was implemented in the magneto-assay to shorten the incubation times and improve assay performance. As we show, the shortened magneto-assay could be carried out in about 35 min, which included two 5-min incubations, washing, and incubation with enzyme substrate for 20 min before colorimetric detection. Moreover, the quantification of MMP-9 provided by the shortened assay in 12 plasma samples collected from patients was comparable to that generated by the 5-h ELISA, which was 8.5 times longer.

    更新日期:2017-11-11
  • Regulating immobilization performance of metal-organic coordination polymers through pre-coordination for biosensing
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-10
    Hua Yang, Xin Qi, Xinquan Wang, Xiangyun Wang, Qiang Wang, Peipei Qi, Zhiwei Wang, Xiahong Xu, Yingchun Fu, Shouzhuo Yao

    We propose a method for regulating biomolecules immobilization performance of metal-organic coordination polymers (MOCPs) through pre-coordination for highly sensitive biosensing. 2,5-dimercapto-1,3,4-thiadiazole (DMcT) was used as organic monomers. Firstly, using CuCl2 as the source of metal ions to form short oligomers with DMcT (MOCPsCu), which can regulate the length of ligands through pre-coordination. Then exploiting NaAuCl4 as the source of Au ions to coordinate both short oligomers and biomolecules (MOCPsCu+Au), since Au ions can coordinate with both N and S atoms. Through controlling the concentration of CuCl2, oligomers with desired length could be readily obtained to prepare MOCPsCu+Au framework with controllable porosity and enzyme entrapment efficiency. Thus MOCPsCu+Au offers several advantages including improved mass transfer efficiency and biocatalytic sensitivity than conventional MOCPs using single metal ions. Glucose oxidase (GOx) was used as the representative biomolecule, the entrapment ratio of enzyme in MOCPsCu+Au case reached an extreme value of 100%. These MOCPsCu+Au biocomposites modified electrode also showed greatly enhanced biocatalytic sensitivity (127 μA cm−2 mM−1) and very low detection limit (58 nM), compared with those reported analogues. The new materials/strategy may create new avenue to regulate the performance of ligand-constructed polymers and their composites for entrapment-based applications.

    更新日期:2017-11-11
  • Water-based alkyl ketene dimer ink for user-friendly patterning in paper microfluidics
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-10
    Nurul Nadiah Hamidon, Yumiao Hong, Gert I.J. Salentijn, Elisabeth Verpoorte

    We propose the use of water-based alkyl ketene dimer (AKD) ink for fast and user-friendly patterning of paper microfluidic devices either manually or using an inexpensive XY-plotter. The ink was produced by dissolving hydrophobic AKD in chloroform and emulsifying the solution in water. The emulsification was performed in a warm water bath, which led to the evaporation of chloroform. Subsequent rapid cooling led to the final product, an aqueous suspension of fine AKD particles. The effects of surfactant and AKD concentrations, emulsification procedure, and cooling approach on final ink properties are presented, as along with an optimized protocol for its formulation. This hydrophobic agent was applied onto paper using a plotter pen, after which the paper was heated (cured) to allow spreading of AKD molecules and chemical bonding with cellulose. A paper surface patterned with the ink (10 g L−1 AKD) yielded a contact angle of 135.6° for water. Unlike organic solvent-based solutions of AKD, this AKD ink does not require a fume hood for its use. Moreover, it is compatible with plastic patterning tools, due to the effective removal of chloroform in the production process to less than 2% of the total volume. Furthermore, this water-based ink is easy to prepare and use. Finally, the AKD ink can also be used for the fabrication of so-called selectively permeable barriers for use in paper microfluidic networks. These are barriers that stop the flow of water through paper, but are permeable to solvents with lower surface energies. We applied the AKD ink to confine and preconcentrate sample on paper, and demonstrated the use of this approach to achieve higher detection sensitivities in paper spray ionization-mass spectrometry (PSI-MS). Our patterning approach can be employed outside of the analytical lab or machine workshop for fast prototyping and small-scale production of paper-based analytical tools, for use in limited-resource labs or in the field.

    更新日期:2017-11-11
  • Ultrasensitive flexible FET-type aptasensor for CA 125 cancer marker detection based on carboxylated multiwalled carbon nanotubes immobilized onto reduced graphene oxide film
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-10
    Samira Mansouri Majd, Abdollah Salimi

    The development of a novel flexible and ultrasensitive aptasensor based on carboxylated multiwalled carbon nanotubes (MWCNTs)/ reduced graphene oxide-based field effect transistor (FET) has been reported for label-free detection of the ovarian cancer antigen 125 (CA125). The fabricated sensor has a straightforward design based on the noncovalent attachment of MWCNTs/aptamer conjugated onto few layers reduced graphene oxide nanosheets and its integration with poly-methyl methacrylate (PMMA) as a suitable platform for designing flexible field-effect transistors. The surface properties of the aptasensor were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Under optimal conditions, the proposed aptasensor exhibited a wide linear dynamic range for CA125 (1.0 × 10−9-1.0 U/mL) with a low detection limit of 5.0 × 10−10 U/mL. The proposed aptasensor was also successfully applied to detect CA125 in real human serum samples. Furthermore, sensor flexibility is also a challenging area in chemical and biological sensors, especially for portable, wearable, or even implantable sensors, so, the reduced graphene oxide-based FET-type aptasensor showed bendable flexibility on the PMMA substrate. In addition, the aptasensor exhibited high sensitivity, selectivity, stability and reproducibility which offers great promise as a high performance and flexible FET-type aptasensor to detect CA125 and other cancer biomarkers in clinical samples and biological fluids.

    更新日期:2017-11-11
  • The effect of hematocrit on solid-phase microextraction ☆
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-10
    Nathaly Reyes-Garcés, Md Nazmul Alam, Janusz Pawliszyn

    Solid-phase microextraction (SPME) is an approach to sample preparation that has demonstrated its appropriateness for isolating/enriching analytes present in complex biofluids with minimum sample pre-treatment. Several prior in vitro and in vivo studies have used SPME to monitor the concentrations of various drugs and metabolites in blood samples. In this work, we present the results of an investigation into how various levels of hematocrit (Hct) affect SPME recoveries. The matrices for this study consisted of whole blood samples that had been adjusted at three different Hct levels (20%, 45%, and 70%), and the selected model compounds were drugs with different physicochemical characteristics (log P range from 0.33 to 6.36). In addition, two experimental setups were employed to conduct the extractions: hydrophilic lipophilic balanced (HLB) coated SPME devices (HLB-D) at 1500 rpm (vortex agitation), and mixed mode SPME fibres (MM-F) at 400 rpm (orbital shaking agitation). Our results demonstrated that the Hct effect in SPME is dependent on the analytes of interest, and that different outcomes can be attained by altering experimental conditions, such as coating type, convection, and extraction time. Interestingly, a target compound's relative affinity for the matrix components and for the coating material proved to be one of the main factors that determine the final effect that different erythrocyte levels have on SPME recoveries. Finally, although the Hct content affects each analyte differently and the final Hct effect depends on the experimental parameters, matrix variability can be corrected by using appropriate internal standards, thereby resulting in correct quantification.

    更新日期:2017-11-11
  • Enhanced fluidity liquid chromatography of inulin fructans using ternary solvent strength and selectivity gradients
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Raffeal Bennett, Susan V. Olesik

    The value of exploring selectivity and solvent strength ternary gradients in enhanced fluidity liquid chromatography (EFLC) is demonstrated for the separation of inulin-type fructans from chicory. Commercial binary pump systems for supercritical fluid chromatography only allow for the implementation of ternary solvent strength gradients which can be restrictive for the separation of polar polymeric analytes. In this work, a custom system was designed to extend the capability of EFLC to allow tuning of selectivity or solvent strength in ternary gradients. Gradient profiles were evaluated using the Berridge function (RF1), normalized resolution product (NRP), and gradient peak capacity (Pc). Selectivity gradients provided the separation of more analytes over time. The RF1 function showed favor to selectivity gradients with comparable Pc to that of solvent strength gradients. NRP did not strongly correlate with Pc or RF1 score. EFLC with the hydrophilic interaction chromatography, HILIC, separation mode was successfully employed to separate up to 47 fructan analytes in less than 25 min using a selectivity gradient.

    更新日期:2017-11-10
  • A highly sensitive gold nanoparticle-based electrochemical aptasensor for theophylline detection
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Xifeng Chen, Zhenzhen Guo, Yuguo Tang, Ying Shen, Peng Miao

    Theophylline is a common bronchodilator for the treatment of diseases like asthma, bronchitis and emphysema. However, it should be strictly used and monitored due to its toxicity when the concentration is above certain levels. In this work, an electrochemical biosensor for theophylline detection is proposed by recognition of RNA aptamer and gold nanoparticle (AuNP)-based amplification technique. First, RNA aptamer is splitted into two single-stranded RNA probes. One is hybridized with DNA tetrahedron and the resulted nanostructure is then immobilized onto a gold electrode; the other is modified on the surface of AuNPs which is also labeled with methylene blue (MB) as electrochemical species. The recognition process between the two RNA probes and theophylline causes the localization of AuNPs and the enrichment of MB on the electrode interface. A significant electrochemical response is thus generated which is related to the concentration of initial theophylline. This proposed aptasensor shows excellent sensitivity and selectivity which could also be applied in quantitatively detection of theophylline in serums samples.

    更新日期:2017-11-10
  • Development and validation of a LC/MS-based method for the measurement of intracellular superoxide anion
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Ze-Yuan Wang, Yi Li, Wen-Qi Chang, Jia-Yi Zheng, Ping Li, Li-Fang Liu, Gui-Zhong Xin

    Superoxide anion (O2.-), as the first generated reactive oxygen species (ROS), has been considered to be highly deleterious to cell functions. The measurement of intracellular O2.- level is of great importance to uncover its roles in a variety of oxidative damage diseases. Hydroethidium (HE) fluorescence-based method is dominating intracellular O2.- assay by monitoring the unique product 2-OH-E+ of HE/O2.- reaction. However, the avoid-less cross-interference of red fluorescence limited its ability to provide trustworthy information on intracellular O2.- formation. By the detection of 2-OH-E+, we herein developed and validated an improved LC/MS-based method for the measurement of intracellular O2.-. Firstly, we demonstrated the proportionality of HE/O2.- reaction. Secondly, ungerimine was used as internal standard to eliminate daily basis and matrix effect in the LC/MS-based detection of 2-OH-E+. Afterward, the total protein concentration was utilized for cell number normalization. Accordingly, an equation was further proposed to calculate the relative abundance (RA) of intracellular O2.-. Finally, the developed method has been successfully utilized to evaluate the inhibitory effects of natural compounds on O2.- generation, the result of which was validated by the HE-based fluorescent measurement. Compared with the fluorescent measurement, the LC/MS-based intracellular O2.- assay method is more sensitive, selective and accurate.

    更新日期:2017-11-10
  • QCM-based rapid detection of PCR amplification products of Ehrlichia canis
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Kespunyavee Bunroddith, Nareerat Viseshakul, Kosum Chansiri, Peter Lieberzeit

    Ehrlichia canis is an intracellular parasitic bacterium and arthropod-borne pathogen that receives growing attention, because it leads to increasing morbidity and mortality in animals. It does so by causing canine monocytotropic ehrlichiosis (CME). Infected canines may lack obvious clinical signs and stay in chronic stage. Herein we report a rapid screening method based on PCR assay combined with quartz crystal microbalance (QCM) to design a DNA sensor for detecting E. canis in early stages of infection. The test relies on DNA amplification of target nucleotide sequences via PCR followed by detecting DNA-DNA hybridization using QCM. The approach did not result in any cross-hybridization toward other blood bacteria or parasites in dogs, such as Anaplasma platys, Babesia canis and Trypanosoma spp, but turned out selective for the target species. The limit of detection of QCM was as low as 4.1 × 109 molecules/μl of 289 bp E. canis PCR products corresponding to 22 copy numbers/μl of E. canis. Furthermore, the technique is also simple, does not require complicated equipment and can in principle be reused.

    更新日期:2017-11-10
  • Rapid differentiation of Ganoderma species by direct ionization mass spectrometry
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Ho-Yi Wong, Melody Yee-Man Wong, Bin Hu, Pui-Kin So, Chi-On Chan, Daniel Kam-Wah Mok, Zhong-Ping Yao

    In this study, direct ionization mass spectrometry (DI-MS) has been developed for rapid differentiation of Ganoderma (known as Lingzhi in Chinese), a very popular and valuable herbal medicine. Characteristic mass spectra can be generated by DI-MS directly from the raw herbal medicines with the application of a high voltage and solvents. Rapid differentiation of the Ganoderma species that are officially stated in the Chinese pharmacopoeia from easily confused Ganoderma species could be achieved based on this method, as the acquired DI-MS spectra showed that ganoderic acids, the major active components of Ganoderma, could be found only in the official Ganoderma species but not in the confused Ganoderma species. In addition, classification of wild and cultivated Ganoderma and potential differentiation of Ganoderma from different geographical locations could be accomplished based on principal component analysis (PCA) or hierarchical clustering analysis (HCA). The method is rapid, simple and reproducible, and can be further extended to analysis of other herbal medicines.

    更新日期:2017-11-10
  • Needle-based sampling coupled with colorimetric reaction catalyzed by layered double hydroxide peroxidase mimic for rapid detection of the change of d-glucose levels with time in bananas
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Wei Shen, Jun Sun, Jowy Yi Hoong Seah, Lei Shi, Sheng Tang, Hian Kee Lee

    For analyte detection in raw fruits, the conventional sample pretreatment method usually involves mashing (blending or homogenization), extraction, and dilution. This process is time-consuming, solvent-intensive and laborious. Usually, there is also a lot wastage with multiple fruits being combined into composite samples. In this work, a new micro-sampling approach based on a syringe needle is developed; it was coupled with micro liquid-phase extraction to determine and quantify d-glucose in bananas. This sampling and extraction approach was quick, easy and required only minimal use of solvent. The d-glucose in the extracted banana flesh was first oxidized enzymatically with glucose oxidase. The resulting peroxide was then detected colorimetrically via oxidation of 3,3′,5,5′-tetramethylbenzidine in the presence of a catalyst. The latter, consisting of an iron (III)–nickel (II) layered double hydroxide (LDH[NiII-FeIII]) was synthesized in this work for the purpose. The results of this new detection method for d-glucose in fruits provided low limits of detection (0.025 μg/mL), wide linear range (0.1–3000 μg/mL) and good linearity (r2 = 0.9998). Quantification of d-glucose using this approach was applied to banana samples over a period of 10 days. The results showed that the d-glucose levels in bananas increased as the fruits ripened, as expected. This work demonstrated a new and interesting approach for easy and efficient detection of analytes in raw fruit samples.

    更新日期:2017-11-10
  • Development of a modified QuEChERS method for multi-class pesticide analysis in human hair by GC-MS and UPLC-MS/MS
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Edouard Lehmann, Christelle Oltramare, Luiz Felippe de Alencastro

    The present study assessed the suitability of using QuEChERS procedure for the simultaneous determination and quantification of 37 multi-class pesticides in human hair. Matrix co-eluted material had a large influence on instrumental response sensitivity. Purification was needed although dSPE cleanup sorbent selection critically influenced analyte recovery. Optimized protocol using Z-Sep+sorbent successfully achieved recovery of 28 pesticides with high sensitivity, precision, and accuracy. Limits of detection ranged from 0.2 to 86.6 pg mg−1 and from 0.5 to 6.3 pg mg−1 for GC and UPLC amenable substances respectively. Pyrethroid pesticides were the most influenced by matrix effects which explained the higher limits of quantification retained for these substances. On the contrary, high sensitivity was achieved for UPLC amenable substances (LOD < 1 pg mg−1 for atrazine, deisopropylatrazine, desethylatrazine, and imidacloprid). Suitability for monitoring pesticide exposure was assessed by application of the proposed protocol to samples collected on the field. Hairs of the volunteers were found positive to 8 pesticides with every sample containing at least one residue. Among these pesticides, only 3 were reported as used in local vegetable production, which suggested other sources of exposure. The developed method offers a sensitive, robust, and accessible tool for biomonitoring of human exposure.

    更新日期:2017-11-10
  • An integrated method for simultaneously determining 10 classes of per- and polyfluoroalkyl substances in one drop of human serum
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Ke Gao, Jianjie Fu, Qiao Xue, Yili Li, Yong Liang, Yuanyuan Pan, Aiqian Zhang, Guibin Jiang

    Per- and polyfluoroalkyl substances (PFASs) represent a group of synthetic chemicals, and they have quite different physicochemical properties, which result in difficulties of their simultaneous determination in a single injection. A sensitive, reliable, and fully automated method was developed for simultaneously detecting 10 classes of PFASs (total of 43) in human serum using online Turboflow SPE-UHPLC-MS/MS. This method provided high linearity of matrix-matched calibration standards (R > 0.99), excellent method limits of detection (MLODs) (0.013–0.089 ng mL−1), satisfactory matrix spiked recoveries (84.3%–109%) and relative standard deviations (RSDs) (intra-day RSDs: 1.3%–12.6%, inter-day RSDs: 1.7%–13.8%, inter-week RSDs: 1.8–13.5%, inter-month RSDs: 3.1–12.4%), short analysis time (19 min per sample) and small sample amount requirement (25 μL), which were suitable for large-scale epidemiologic studies. Moreover, the method provided the feasibility of real-time monitoring for the degradation kinetics of PFASs precursors both in vitro and in vivo. The quality of the present method was further verified by repetitive analysis of a standard reference material (SRM 1957), with the deviations of the targeted PFAS concentrations ranging from 1.9% to 14.2% (n = 5) between the detected and reference values. The present study also determined values for several PFASs in SRM 1957 other than those on the certificate, for the first time, such as N-EtFOSA, 6:2 Cl-PFESA, and PFBA. Finally, the established method was applied to detect PFASs in serum samples of 15 ordinary people and 15 occupational workers, and 6:2 FTSA was found as the dominant precursor.

    更新日期:2017-11-10
  • A novel triplex isobaric termini labeling quantitative approach for simultaneously supplying three quantitative sources
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-09
    Hucong Jiang, Hongrui Yin, Liqi Xie, Ying Zhang, Lei Zhang, Peng-Yuan Yang, Haojie Lu

    Benefiting from high sensitivity and great ability to measure multiple samples simultaneously, isobaric tandem Mass spectrometry (MS2) quantification has been widely applied for protein biomarker screening. Here, a newly developed isobaric MS2 quantification method named triplex quantification by isobaric termini labeling (Triplex-QITL) was established. This method enables the accurate comparison of various fragment ions (reporter ions, amino acid fragments and N-/C-terminal fragments) based quantification to be operated in a single run. To our knowledge, this is the first time that this kind of comparison is achieved. In Triplex-QITL, proteins were first digested with Lys-C to produce peptides with lysine (K) at the C-termini, then dimethylation reagents and mTRAQ reagents were used to label the N-termini and C-termini of the peptides respectively. N- and C-terminal fragment ion pairs, reporter ions from mTRAQ (113,117,121) and a1 ion pairs were simultaneously generated in MS2 spectra. In simple sample experiment, not much difference in using various fragment ions for quantification was observed. When analyzing SW480 cell lysate, comparing with a1 ions, about two times of reproducible quantification results were achieved by reporter ions and N- and C-terminal ions. Meanwhile the measured quantification results were much closer to the expected results even in large ratios (1:10:10) using N- and C-terminal ions. Finally, Triplex-QITL was successfully applied to profile metastatic differences of three hepatocellular carcinoma (HCC) cell lines. In all, Triplex-QITL shows a promising future in quantitative proteomics.

    更新日期:2017-11-10
  • Rapid determination of immunosuppressive drug concentrations in whole blood by coated blade spray-tandem mass spectrometry (CBS-MS/MS)
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-08
    Germán Augusto Gómez-Ríos, Marcos Tascon, Nathaly Reyes-Garcés, Ezel Boyacı, Justen James Poole, Janusz Pawliszyn

    Coated Blade Spray (CBS) is a technology that efficiently integrates sample preparation and direct coupling to mass spectrometry (MS) on a single device. In this article, we present CBS-tandem mass spectrometry (CBS-MS/MS) as a novel tool for the rapid and simultaneous determination of four commonly used immunosuppressive drugs (ISDs) in whole blood: tacrolimus (TAC) and cyclosporine-A (CycA), which are calcineurin inhibitors; and sirolimus (SIR) and everolimus (EVR), which are both mTOR (mechanistic target of rapamycin) inhibitors. Given that CBS extracts via free concentration, analytes that are largely bound to plasma proteins or red blood cells provide considerably lower extraction recovery rates. Therefore, we defy the solventless philosophy of SPME-based techniques, like CBS, by performing the analyte-enrichment step via direct immersion in a solvent-modified matrix. The assay was linear within the evaluated range of concentrations (between 1 and 100 ng/mL for EVR/SIR/TAC and 10–1000 ng/mL for CycA), and the limits of quantification were determined to be 10 ng/mL for CycA and 1 ng/mL for EVR/SIR/TAC. Good accuracy (87–119%) and linearity (r2 ≥ 0.99) were attained over the evaluated range for all ISDs. Interassay imprecision (CV) determined from incurred sample reanalysis was ≤10% for all ISDs. Our method was validated using Liquichek™ whole blood immunosuppressant quality control (QC) standards purchased from Bio-Rad. Concentrations determined by CBS-MS/MS were inside the range specified by Bio-Rad and within 15% of the expected mean value for all ISDs at all QC levels. Furthermore, the effect of different hematocrit levels (20, 45, and 70%) in the entire calibration range was carefully studied. No statistical differences (RSD ≤ 7%) in the calibration curve slopes of ISDs in blood were observed. CBS offers a simpler workflow than that of traditional methods; it eliminates the need for chromatographic separation and provides a clean extract that allows for long-term MS instrumental operation with minimal maintenance. Additionally, because CBS integrates all analytical steps into one device, it eliminates the risk of instrumental carry-over and can be used as a low-cost disposable device for sample preparation and analysis. Fully-automated sample preparation simplifies the method and allows for total analysis times as short as 3 min with turn-around times of less than 90 min.

    更新日期:2017-11-10
  • Behavior and kinetic of hydrolysis of amine boranes in acid media employed in chemical vapor generation
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-03
    Lucia D'Ulivo, Roberto Spiniello, Massimo Onor, Beatrice Campanella, Zoltan Mester, Alessandro D'Ulivo
    更新日期:2017-11-03
  • Tutorial: Correction of shifts in single-stage LC-MS(/MS) data
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-02
    Vikram Mitra, Age Smilde, Rainer Bischoff, Péter Horvatovich
    更新日期:2017-11-03
  • Mass spectrometry based analytical approaches and pitfalls for toxicometabolomics of arsenic in mammals: A tutorial review
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-11-02
    T. García-Barrera, G. Rodríguez-Moro, B. Callejón-Leblic, A. Arias-Borrego, J.L. Gómez-Ariza
    更新日期:2017-11-03
  • 更新日期:2017-10-31
  • A simple and sensitive competitive bio-barcode immunoassay for triazophos based on multi-modified gold nanoparticles and fluorescent signal amplification
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-30
    Chan Zhang, Pengfei Du, Zejun Jiang, Maojun Jin, Ge Chen, Xiaolin Cao, Xueyan Cui, Yudan Zhang, Ruixing Li, A.M. Abd El-Aty, Jing Wang
    更新日期:2017-10-31
  • Chromatographic separation of the theranostic radionuclide 111Ag from a proton irradiated thorium matrix
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-30
    Tara Mastren, Valery Radchenko, Jonathan W. Engle, John W. Weidner, Allison Owens, Lance E. Wyant, Roy Copping, Mark Brugh, F. Meiring Nortier, Eva R. Birnbaum, Kevin D. John, Michael E. Fassbender
    更新日期:2017-10-30
  • Hydrogel-based suspension array for biomarker detection using horseradish peroxidase -mediated silver precipitation
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-30
    Dina Shohatee, Joshua Keifer, Nicholas Schimmel, Swetaparna Mohanty, Gargi Ghosh
    更新日期:2017-10-30
  • Thread based electrofluidic platform for direct metabolite analysis in complex samples
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-28
    Joan M. Cabot, Michael C. Breadmore, Brett Paull
    更新日期:2017-10-28
  • 更新日期:2017-10-27
  • Novel immunochromatographic assay based on Eu (III)-doped polystyrene nanoparticle-linker-monoclonal antibody for sensitive detection of Escherichia coli O157:H7
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-27
    Ke-Yu Xing, Juan Peng, Dao-Feng Liu, Li-Ming Hu, Chun Wang, Guo-Qiang Li, Gang-Gang Zhang, Zhen Huang, Song Cheng, Fang-Fei Zhu, Na-Mei Liu, Wei-Hua Lai
    更新日期:2017-10-27
  • A fluorescence aptasensor based on two-dimensional sheet metal-organic frameworks for monitoring adenosine triphosphate
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-27
    Xiao-man Hai, Nan Li, Ke Wang, Zhi-qi Zhang, Jing Zhang, Fu-quan Dang
    更新日期:2017-10-27
  • 更新日期:2017-10-27
  • 更新日期:2017-10-27
  • Inner filter effect-based fluorescent sensing systems: A review
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-27
    Shuai Chen, Yong-Liang Yu, Jian-Hua Wang
    更新日期:2017-10-27
  • Simultaneous determination of renal function biomarkers in urine using a validated paper-based microfluidic analytical device
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-27
    Eduardo Luiz Rossini, Maria Izabel Milani, Emanuel Carrilho, Leonardo Pezza, Helena Redigolo Pezza
    更新日期:2017-10-27
  • An ultra-sensitive fluorescent “Turn on” biosensor for glutathione and its application in living cells
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-27
    Wei Wang, Xiaoshan Hou, Xin Li, Chen Chen, Xiliang Luo
    更新日期:2017-10-27
  • 更新日期:2017-10-27
  • 更新日期:2017-10-27
  • Surface sieving coordinated IMAC material for purification of His-tagged proteins
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-27
    Senwu Li, Kaiguang Yang, Lukuan Liu, Baofeng Zhao, Yuanbo Chen, Xiao Li, Lihua Zhang, Yukui Zhang
    更新日期:2017-10-27
  • 更新日期:2017-10-27
  • Photometric flow analysis system for biomedical investigations of iron/transferrin speciation in human serum
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-23
    Kamil Strzelak, Natalia Rybkowska, Agnieszka Wiśniewska, Robert Koncki
    更新日期:2017-10-23
  • The differences in matrix effect between supercritical fluid chromatography and reversed phase liquid chromatography coupled to ESI/MS
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-23
    Alfred Svan, Mikael Hedeland, Torbjörn Arvidsson, Curt E. Pettersson
    更新日期:2017-10-23
  • Optimization of GC/TOF MS analysis conditions for assessing host-gut microbiota metabolic interactions: Chinese rhubarb alters fecal aromatic Amino acids and phenol metabolism
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-19
    Shan Yin, Pan Guo, Dafu Hai, Li Xu, Jiale Shu, Wenjin Zhang, Muhammad Idrees Khan, Irwin J. Kurland, Yunping Qiu, Yumin Liu
    更新日期:2017-10-19
  • High throughput screening of phenoxy carboxylic acids with dispersive solid phase extraction followed by direct analysis in real time mass spectrometry
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-18
    Jiaqin Wang, Jun Zhu, Ling Si, Qi Du, Hongli Li, Wentao Bi, David Da Yong Chen
    更新日期:2017-10-19
  • Low-background and visual detection of antibiotic based on target-activated colorimetric split peroxidase DNAzyme coupled with dual nicking enzyme signal amplification
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-18
    Xuejun Cui, Rongguo Li, Xiaofei Liu, Jingfeng Wang, Xueqi Leng, Xiaolei Song, Qianqian Pei, Yu Wang, Su Liu, Jiadong Huang
    更新日期:2017-10-19
  • Label-free determination of prostate specific membrane antigen in human whole blood at nanomolar levels by magnetically assisted surface enhanced Raman spectroscopy
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-17
    Zuzana Chaloupková, Anna Balzerová, Jitka Bařinková, Zdenka Medříková, Pavel Šácha, Petr Beneš, Václav Ranc, Jan Konvalinka, Radek Zbořil
    更新日期:2017-10-18
  • 更新日期:2017-10-18
  • Advances in sensing and biosensing of bisphenols: A review
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-17
    Dhanjai, Ankita Sinha, Lingxia Wu, Xianbo Lu, Jiping Chen, Rajeev Jain
    更新日期:2017-10-18
  • 更新日期:2017-10-18
  • Identification of new tetrahydroxylated metabolites of Polycyclic Aromatic Hydrocarbons in hair as biomarkers of exposure and signature of DNA adduct levels
    Anal. Chim. Acta (IF 4.95) Pub Date : 2017-10-17
    Nathalie Grova, Jean-Philippe Antignac, Emilie M. Hardy, Fabrice Monteau, Karine Pouponneau, Bruno Le Bizec, Brice M.R. Appenzeller
    更新日期:2017-10-18
  • 更新日期:2017-10-17
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.
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