首页期刊导航|Journal of chromatography
期刊信息/Journal information
Journal of chromatography
Elesevier
Journal of chromatography

Elesevier

0021-9673

Journal of chromatography/Journal Journal of chromatographySCIISTPCCR
正式出版
收录年代

    Capillary electrophoresis for enzyme-based studies: Applications to lipases and kinases

    Banni, Ghassan Al Hamoui DitNehme, Reine
    23页
    查看更多>>摘要：Capillary electrophoresis (CE) is a powerful technique continuously expanding into new application fields. One of these applications involves the study of enzymes, their catalytic activities and the alteration of this activity by specific ligands. In this review, two model enzymes, lipases and kinases, will be used since they differ substantially in their modes of action, reaction requirements and applications making them perfect subjects to demonstrate the advantages and limitations of CE-based enzymatic assays. Indeed, the ability to run CE in various operation modes and hyphenation to different detectors is essential for lipase-based studies. Additionally, the low sample consumption provided by CE promotes it as a promis-ing technique to assay human and viral nucleoside kinases. Undeniably, these are rarely commercially available enzymes and must be frequently produced in the laboratory, a process which requires special sets of skills. CE-based lipase and kinase reactions can be performed outside the capillary (pre-capillary) where the reactants are mixed in a vial prior to their separation or, inside the capillary (in-capillary) where the reactants are mixed before the electrophoretic analysis. These enzyme-based applications of CE will be compared to those of liquid chromatography-based applications in terms of advantages and limitations. Binding assays based on affinity CE and the compelling microscale thermophoresis (MST) will be briefly presented as they allow a broad understanding of the molecular mechanism behind ligand binding and of the resulting modulation in activity. (c) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Towards comprehensive non-target screening using heart-cut two-dimensional liquid chromatography for the analysis of organic atmospheric tracers in ice cores

    Beschnitt, AnjaSchwikowski, MargitHoffmann, Thorsten
    12页
    查看更多>>摘要：Non-target screening of secondary organic aerosol compounds in ice cores is used to reconstruct atmospheric conditions and sources and is a valuable tool to elucidate the chemical profiles of samples with the aim to obtain as much information as possible from one mass spectrometric measurement. The coupling of mass spectrometry to chromatography limits the results of a non-target screening to signals of compounds within a certain polarity range based on the utilized stationary phases of the columns. Comprehensive two-dimensional liquid chromatography (LCxLC) introduces a second column of different functionality to enable the analysis of a broader range of analytes. Conventional LCxLC requires complex instrumental setups and is difficult to implement for most laboratories. In this work we demonstrate an approach to approximate a comprehensive non-target screening using a simple instrumental setup employing two columns of orthogonal functionalities (HILIC and reversed-phase), an additional pump, and an additional six-port valve. The void volume of the first dimension is transferred to the reversed-phase column to analyze low-polarity compounds during the re-equilibration of the HILIC. Method validation showed adequate repeatability and detection limits for two selected void volume markers and application to snow samples collected at the high-alpine research station Jungfraujoch yielded a total of 270 signals. Comparison to the one-dimensional HILIC approach revealed 175 signals exclusively detected in the two-dimensional method, of which 23 were detected in the second dimension. Detailed analysis of the chemical composition showed consistency with expected compounds in snow samples like lignin or cellulose combustion products from biomass burning or secondary organic aerosol constituents. The results confirmed that one-dimensional chromatography was not sufficient to cover the entire range of compounds and the developed two-dimensional approach will improve the information content from non-target screening while maintaining time of analysis and a simple instrumental setup. (c) 2021 Published by Elsevier B.V.
      原文链接:
    • NSTL
    • Elsevier

    Highly sensitive novel fluorescent chiral probe possessing (S)-2-methylproline structures for the determination of chiral amino compounds by ultra-performance liquid chromatography with fluorescence: An application in the saliva of healthy volunteer

    Li, Xi-LingHan, YuHuang, YuanSun, Xiaoqi...
    12页
    查看更多>>摘要：We developed a novel fluorescent chiral probe, DBD-trans-2-methyl-L-proline (DBD-M-Pro), which can be used to target recognition of amino functional groups using chiral resolution. To investigate the chiral resolution efficiency, 20 chiral amino enantiomers (19 DL-amino acids and phenylethylamine) were labeled using ultra-performance liquid chromatography (UPLC) with a fluorescence (FL) system. Diastereomers were formed by the reactions of DBD-M-Pro with enantiomers of amino functional groups at 60 degrees C for 60 mM and detected on a BEH C18 column (100 x 2.1 mm, 1.7 mu m). Gradient elution of 10 mM ammonium acetate with 0.05% formic acid (FA) aqueous solution and 0.1% FA acetonitrile or 0.1% FA methanol solution was performed at an excitation wavelength (Ex) 460 nm and emission wavelength (Em) 550 nm. Each resulting derivative of D- and L- type was effectively separated. The results showed that the resolution (Rs) of 17 amino acids and phenylethylamine (PEA) in the range of 1.59-24.11, except for histidine (His) (Rs = 1.32) and serine (Ser) (Rs = 1.47), achieved completely separation. The DBD-M-Pro chiral probe has a robust chiral selectivity for D-amino acids. Furthermore, a new method for the simultaneous determination of six DL-amino acids (Pro, Val, Trp, Phe, Leu, Lys) in human saliva was developed. The proposed method showed resolution values of 1.78-16.38, and an excellent linear relationship was obtained in the range of 2.5-500 pmol (R-2 >= 0.9990). The limit of detection (S/N = 3) ranged from 0.5 to 3.75 pmol. The intra-day and inter-day coefficient of variation (CV) were within the range of 1.75-11.73%. The average addition recoveries in saliva ranged from 95.99 to 106.97%. The methodology was used to determine the content of DL-amino acids and the D/L-amino acid ratio in the saliva of 40 healthy volunteers (15 males and 25 females), as well as evaluating the differences between men and women. Our study suggests that the DBD-M-Pro chiral probe could be an effective tool for screening potential D-amino acid biomarkers in disease. (C) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Chiral stationary phases based on lactide derivatives for high-performance liquid chromatography

    Wen, TaoZeng, GuangjianGao, YutingLi, Xinyu...
    8页
    查看更多>>摘要：Lactide is a natural and renewable lactone cyclic ester-containing intrinsic chiral center, providing an affordable natural compound that is potential for the development of chiral polymers. In this work, we reported two novel chiral stationary phases (CSPs) based on lactide derivatives, methylene lactide (MLA), for high-performance liquid chromatography (HPLC). By using free radical polymerization, chemically bonded CSPs of poly(methylene lactide) (PMLA) and side-chain modified PMLA by aminolysis (N-PMLA) can be prepared. Also, poly(L-lactic acid) (PLLA) was prepared as a control. The chiral resolution performance of the chromatographic columns was examined in both reversed-phase and normal-phase modes. PMLA and N-PMLA CSPs exhibited fairly good chiral recognition ability, whereas the separation ability of PLLA is much weaker. This work provides a new platform for the development of high-performance CSPs from affordable natural products. (C) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Structural characterization of methyl-beta-cyclodextrins by high-performance liquid chromatography and nuclear magnetic resonance spectroscopy and effect of their isomeric composition on the capillary electrophoresis enantioseparation of daclatasvir

    Scriba, Gerhard K. E.Krait, SulaimanSalgado, AntonioMalanga, Milo...
    9页
    查看更多>>摘要：The separation of daclatasvir and its R,R,R,R-enantiomer was studied by capillary electrophoresis using various randomly methylated beta-CDs and the single isomer heptakis(2,6-di-O-methyl)-beta-CD (2,6-DM-beta-CD) as chiral selectors in an acidic background electrolyte. Opposite enantiomer migration order was observed for randomly substituted CDs compared to 2,6-DM-beta-CD as well as methylated beta-CDs with different composition according to the specifications of the manufacturers. HPLC and NMR analyses confirmed that the presence of a high 2,6-DM-beta-CD content in the CDs enables to achieve the migration order R,R,R,R-enantiomer > daclatasvir. In contrast, products with low 2,6-DM-beta-CD isomer content and/or the presence of a large amount of methylated CD isomers, in which D-glucopyranose moieties are not substituted in either position 2 or 6, displayed the opposite enantiomer migration order daclatasvir > R,R,R,R-enantiomer. The study indicated the importance of the type and composition of derivatized CDs on chiral separations in capillary electrophoresis as well as the importance of proper quality control for cyclodextrin manufacturers. Moreover, the observed migration order could be rationalized based on the composition and substitution pattern of the CDs. (C) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Simultaneous quantification of eleven short-chain fatty acids by derivatization and solid phase microextraction - Gas chromatography tandem mass spectrometry

    Fu, ZhiboJia, QiangqiangZhang, HongyangKang, Lu...
    8页
    查看更多>>摘要：As metabolites of the gut microbiome, short-chain fatty acids (SCFAs) played an important role in the diagnosis of the metabolic diseases. Because of the high polarity, high volatility and complex matrix of biological samples, the highly sensitive, selective and accurate method to determine SCFAs remains a major challenge. Herein, a new method for simultaneous quantification of eleven SCFAs by derivatization combined with solid phase microextraction (SPME) and gas chromatography tandem mass spectrometry (GC-MS/MS) was developed. Isobutyl chloroformate coupled with isobutanol was used as the reaction reagent to derivatize SCFAs. The method validation data showed a satisfactory linearity with the linear regression coefficients (R) ranging from 0.9964 to 0.9996. The limit of detection (LOD) of all SCFAs ranges from 0.01 ng.mL(-1) to 0.72 ng.mL(-1) and the limit of quantification (LOQ) ranges from 0.04 ng.mL(-1) to 2.41 ng.mL(-1) . The intra-day and inter-day precision (RSDs) ranged from 0.65% to 8.92% and 1.62% to 15.61%, respectively. The recovery ranged from 88.10% to 108.71%. Finally, the developed method was successfully used to determine SCFAs in mice fecal sample, and ten of the SCFAs were found in feces of mice, including formic acid. (C) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    A predictive model of organic acids separation by chromatography with strong anionic resins in sulfate form

    Lemaire, JulienZhong, WuyangPerre, PatrickDuval, Fanny...
    13页
    查看更多>>摘要：Organic acids commonly have quite symmetrical chromatography profiles at low pH ( < 1.5) with strong anionic resins, but a significant tailing can be observed with succinic and citric acids. Classical adsorption models, like the Langmuir model, fail to predict this behavior, which can have a major influence on mean retention times and profile shapes, therefore on chromatography performances. A new retention model was developed to better predict organic acid separation with strong anionic resin. This model combines a refined Langmuir adsorption model and an ion-exchange model. Organic acid adsorption is assumed to be due to hydrogen bonding with sulfate and hydrogen sulfate counteranions on the resin. The adsorption capacity depends mostly on molecular size: up to sixteen formic acid molecules could be adsorbed per counter-anions, meanwhile only two succinic acid or one citric acid molecules could be adsorbed. This adsorption model was then embedded in a generic and accurate modeling approach (continuous column with mass balance equations solved by the conservation element/solution element (CE/SE) method). All parameters of this column model were identified by fitting the simulation to experimental results (equilibrium curves and pulse tests). Then, the column model was validated with original experimental results from a binary mixture pulse test (formic and succinic acids). Results show that simulations are much more predictive for multi-component pulse tests, both in terms of profile shape and retention time, which cannot be captured without considering ion-exchange. (c) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Combining high performance thin layer chromatography with minispectrometer-fiber optic probe-coupled to smartphone for in place analysis: Lactose quantification in several matrices

    Martinez-Avino, AdriaMolins-Legua, CarmenCampins-Falco, Pilar
    9页
    查看更多>>摘要：An in place colorimetric method has been proposed for estimation of the quantity of lactose in several matrix (milk, water effluents and surfaces). Analyzing the amount of this carbohydrate it can be control the product, the cleanliness of the parts of the dairy companies and it can avoid contamination of milk products produced there. This method combines the use of HPTLC for sugars separation with novel analytical devices as minispectrophotometer with fiber optic coupled to a smartphone. In order to measure the lactose a colorimetric reaction has been used. Variable volumes of samples or stock solutions were deposited in nano-silica gel layer, a mobile phase of acetonitrile:water:acetic acid was used for carbohydrate separation and a solution of thymol (0.05 g Thymol in 95 mL of EtOH and 5 mL H2SO4) was used for revealed the carbohydrate spot. Finally, the reflectance of samples and stock solutions were measured. The achieved limits of detection were 0.03 mg mL(-1) and 0.003 mg mL(-1) for the working concentration range and the analysis at traces level respectively. (C) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Combination of pipette tip solid phase extraction and high performance liquid chromatography for determination of plant growth regulators in food samples based on the electrospun covalent organic framework/polyacrylonitrile nanofiber as highly efficient sorbent

    Dai, YueCheng, YuanyuanZhang, LingdongKong, Rong-Mei...
    11页
    查看更多>>摘要：Facile and sensitive determination of plant growth regulators (PGRs) in food samples is important but still remains great challenge. Herein, a pipette tip solid phase extraction (PT-SPE) method was de-veloped for fast and sensitively detecting PGRs. The PT-SPE adsorbent was prepared by integrating a novel covalent organic framework (COF) of schiff base network 3 (SNW-3) and polyacrylonitrile (PAN) through electrospinning. The SNW-3 can easily adsorb PGRs with high special affinity through electrova-lent bands between the ammonium ions of SNW-3 and the carboxy groups of PGRs. The polymer of PAN acts as scaffold material for SNW-3, which can lower seepage pressure hence accelerates adsorp-tion/desorption kinetics. By combination with HPLC-DAD, a satisfactory method was successfully devel-oped for simultaneous determination of ten PGRs in watermelon. Good analytical performances were achieved with this proposed method, including good linearity (5-500 ng/mL) with high correlation co-efficients ( R >= 0.9981), low limits of detection (S/N = 3, 0.24-3.19 ng/mL) and limits of quantification (S/N = 10, 1.65-5.72 ng/mL), satisfactory precision (intra-day RSDs < 2.7%, inter-day RSDs < 3.7%), and high accuracy (recovery: 82.8-113.0%). The method developed in this study shows high potential for de-sign of high target-affinity adsorbents for food sample preparing. (c) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier

    Determination of six thyroid hormones in dog brain and liver using acidic extraction, mixed-mode cleanup, and liquid chromatography-tandem mass spectrometry

    Takaguchi, KohkiOno, SumikaTanoue, RumiKunisue, Tatsuya...
    9页
    查看更多>>摘要：Thyroid hormones (THs) play a critical role in the regulation of biological processes, such as growth, metabolism, and development, in various animal species. Prohormone L-thyroxine (T4) is secreted from the thyroid gland and carried to peripheral tissues. T4 is then biotransformed to several metabolites which play different roles, mainly by iodothyronine deiodinases. Determination of deiodinated TH metabolites in key organs such as liver and brain would help to understand tissue-specific TH metabolism and homeostasis. In this study, we thus developed a highly sensitive method for the determination of six THs [T4, 3,5,3'-triodo-L-thyronine (T3), 3,3',5'-triiodo-L-thyronine (rT3), 3,5-diiodo-1-thyronine (3,5-T2), 3,3'-diiodo-1-thyronine (3,3'-T2), and 3-iodo-1-thyronine (3-T1)] in the brain and liver by using stored dog samples. The analytical method consisted of ultrasonic-assisted extraction in acetone acidified with formic acid, cleanup with a EVOLUTE (R) EXPRESS CX cartridge (reversed-phase combined with strong cation-exchange cartridge), and quantification with liquid chromatography-tandem mass spectrometry. Acceptable accuracy (internal standard-corrected recovery: 80%-120%) and intra- and inter-day precision (coefficient of variation: <6% and <15%, respectively) (n = 3/ batch, three days) were obtained for both brain and liver samples. In addition, low method detection limits were achieved for both brain (0.013-0.12 ng g(-1)) and liver (0.030-0.78 ng g(-1)), which resulted in the quantitation of not only T4, T3, and rT3, but also 3,3/-T2 in both dog brain and liver samples. The developed method was successfully applied to the analysis of THs in the brain and liver of dogs (Canis lupus familiaris) which were exposed to polychlorinated biphenyls (PCBs). As a result, concentration ratios of rT3/T4 and 3,3'-T2/T3 in the PCB-exposed dogs were significantly higher than those in the control groups, suggesting the enhanced inner (tyrosyl)-ring deiodination (5-deiodination) by PCB exposure. The analytical method developed in the present study enables comprehensive evaluation of alterations in peripheral TH metabolism which are caused by exposure to environmental pollutants. (C) 2021 Elsevier B.V. All rights reserved.
      原文链接:
    • NSTL
    • Elsevier