23,890 results match your criteria Journal of Chromatography A[Journal]


Preparation and evaluation of dextran-grafted mixed-mode chromatography adsorbents.

J Chromatogr A 2019 Apr 12. Epub 2019 Apr 12.

College of Life Sciences, Huzhou University, Huzhou 313000, China.

In the present work, mixed-mode chromatography adsorbents grafted with dextran of different molecular weight were prepared. Compared to non-grafted adsorbent (BA-6B), the morphology of dextran-grafted adsorbents (BA-6B-Ts) did not change significantly, while the water content (ω), porosity (P) and pore volume (V) decreased. Static adsorption, salt tolerance and dynamic adsorption behaviors of adsorbents BA-6B-Ts against BSA/IgG were studied. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.021DOI Listing

Nerve agent markers screening after accumulation in garden cress (Lepidium sativum) used as a model plant object.

J Chromatogr A 2019 Apr 12. Epub 2019 Apr 12.

Institute of Analytical Chemistry, Johannes Kepler University Linz, Altenberger Strasse 69, 4040, Linz, Austria.

In this research an accumulation of nerve agent markers in garden cress (Lepidium sativum) as a model plant object was studied using LC-QTOF hybrid system. For the determination of methylphosphonic acid and alkyl methylphosphonates, which are specific markers of sarin, soman, VR and VX, simple and sensitive approach was developed. Direct analysis of aqueous extracts on the reversed phase column with polar endcapping allowed to achieve satisfactory retention factor for methylphosphonic acid, which has high polarity and is usually very weakly retained on the ordinary reversed phase columns. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.025DOI Listing

Solid phase extraction of carbamate pesticides with porous organic polymer as adsorbent followed by high performance liquid chromatography-diode array detection.

J Chromatogr A 2019 Apr 13. Epub 2019 Apr 13.

College of Science, Hebei Agricultural University, Baoding 071001, Hebei, China. Electronic address:

A solid phase extraction (SPE) method with a porous organic polymer as adsorbent was established for the extraction of five carbamate pesticides (metolcarb, carbaryl, isoprocarb, bassa and diethofencarb) from milk, white wine and juice samples prior to high performance liquid chromatography-diode array detection. The main factors affecting the SPE were optimized, including sample volume, sample loading rate, sample solution pH, desorption conditions and cartridge reusability. Under the optimal conditions, a good linearity existed in the range from 1. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.031DOI Listing

Development of a new method for the analysis of cannabinoids in honey by means of high-performance liquid chromatography coupled with electrospray ionisation-tandem mass spectrometry detection.

J Chromatogr A 2019 Apr 3. Epub 2019 Apr 3.

Department of Life Sciences, University of Modena and Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy.

Fibre-type Cannabis sativa L. (hemp) represents a valuable resource in many different fields, including both the pharmaceutical and food ones. This plant contains non-psychoactive cannabinoids, a class of bioactive compounds biosynthesized in both female and male inflorescences. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.034DOI Listing
April 2019
1 Read

Bar adsorptive microextraction coated with multi-walled carbon nanotube phases - Application for trace analysis of pharmaceuticals in environmental waters.

J Chromatogr A 2019 Apr 13. Epub 2019 Apr 13.

Centro de Química e Bioquímica e Centro de Química Estrutural, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal. Electronic address:

Bar adsorptive microextraction devices were modified with multi-walled carbon nanotubes for the first time. A bar adsorptive microextraction method followed by microliquid desorption and high-performance liquid chromatography with diode array detection was developed for the determination of trace levels of ketoprofen, diclofenac, gemfibrozil and mefenamic acid in water samples. The mean parameters affecting the bar adsorptive microextraction and microliquid desorption efficiency were studied and optimized using a univariate optimization strategy. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.035DOI Listing

The effect of temperature on the separation of enantiomers with coated and covalently immobilized polysaccharide-based chiral stationary phases.

J Chromatogr A 2019 Apr 13. Epub 2019 Apr 13.

Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Chavchavadze Ave 3, 0179, Tbilisi, Georgia. Electronic address:

This article describes our attempt to re-visit the role of temperature in the separation of enantiomers with polysaccharide-based chiral columns in high-performance liquid chromatography (HPLC). Rarely observed increased retention and separation factors with increasing temperature, as well as temperature dependent reversal of enantiomer elution order are reported for several arylpropionic acid derivatives. Chiral columns with coated and covalently immobilized chiral selectors were compared from the viewpoint of effect of temperature on analyte retention, enantiomer separation and enantiomer elution order. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.024DOI Listing
April 2019
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Amphiphilic triptycene-based stationary phase for high-resolution gas chromatographic separations.

J Chromatogr A 2019 Apr 13. Epub 2019 Apr 13.

Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, and Analysis & Testing Center, Beijing Institute of Technology, Beijing, 100081, China. Electronic address:

This work reports a new type of triptycene-based amphiphilic stationary phase (TP-2IL) for gas chromatography (GC). It is an integration of the 3D π-rich triptycene framework with ionic liquids. Its capillary column showed the efficiency of 3880 plates/m determined by n-dodecane at 120 °C (k = 2. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.033DOI Listing
April 2019
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Development of a new in-line coupling of a miniaturized boronate affinity monolithic column with reversed-phase silica monolithic capillary column for analysis of cis-diol-containing nucleoside compounds.

J Chromatogr A 2019 Apr 15. Epub 2019 Apr 15.

Université de Lyon, CNRS, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, UMR 5280, 5 rue de la Doua, F-69100 VILLEURBANNE, France. Electronic address:

In-line coupling of capillary columns is an effective means for achieving miniaturized and automated separation methods. The use of multimodal column designed to allow the direct integration of a sample preparation step to the separation column is one example. Herein we propose a novel in-line coupling at the capillary scale between a boronate affinity capillary column (μBAMC unit) and a reversed-phase separation column. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.002DOI Listing

Ionic deep eutectic solvents for the extraction and separation of natural products.

J Chromatogr A 2019 Mar 30. Epub 2019 Mar 30.

Research Center of Siyuan Natural Pharmacy and Biotoxicology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang Province 310058, China. Electronic address:

Room ionic liquids (ILs) used as green solvents have received considerable attention and wide application in different research and industrial fields, such as chemistry, biology, catalysis, energy, and even environmental sciences. Recently, a new class of sustainable solvents named deep eutectic solvents (DESs) have been developed, which share the promising solvent characteristics of ILs, such as thermal and chemical stability, low vapor pressure and design ability. In addition, the major advantages of DESs over ILs are their lower prices and easier preparation. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.046DOI Listing
March 2019
1 Read

Analysis of steroids in urine by gas chromatography-capillary photoionization-tandem mass spectrometry.

J Chromatogr A 2019 Mar 28. Epub 2019 Mar 28.

Drug Research Program and Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland. Electronic address:

A new heated capillary photoionization (CPI) ion source design was developed to photoionize analytes inside a transfer capillary between a gas chromatograph (GC) and a mass spectrometer (MS). The CPI setup included a wide, oval-shaped vacuum-ultraviolet (VUV) transparent magnesium fluoride (MgF) window to maximize photoionization efficiency and thus sensitivity. The source contained a nitrogen housing around the ionization chamber inlet to avoid undesirable hydrolysis and oxidation reactions with ambient air and to maximize the proportion of formed molecular radical cations of analytes. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.061DOI Listing

Does local chain conformation affect the chiral recognition ability of an amylose derivative? Comparison between linear and cyclic amylose tris(3,5-dimethylphenylcarbamate).

J Chromatogr A 2019 Apr 10. Epub 2019 Apr 10.

Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka, 560-0043, Japan. Electronic address:

Coated-type chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) were prepared from three cyclic amylose tris(3,5-dimethylphenylcarbamate) (cADMPC) samples, of which weight-average molar mass (M) ranges from 19 to 91 kg mol, and from three linear ADMPC samples ranging in M from 25 to 90 kg mol. CSPs made of cADMPC showed appreciably different chiral separation ability comparing with those for ADMPC with a mixed eluent of n-hexane and 2-propanol. Local conformation plays an important role for the chiral separation taking into account that the local helical structure of cADMPC in dilute solution is extended comparing with ADMPC. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.019DOI Listing

Development of a design of experiments optimized method for quantification of polysorbate 80 based on oleic acid using UHPLC-MS.

J Chromatogr A 2019 Apr 8. Epub 2019 Apr 8.

Almirall Hermal GmbH, Reinbek, Germany; RaDes GmbH, Hamburg, Germany.

The aim was to develop a straightforward UHPLC-MS quantification method for polysorbate 80 using oleic acid as surrogate marker, which was the commonest substance within the emulsifier. However, hydrolysis of polysorbate 80 and subsequent analysis of fatty acids revealed a co-elution of oleic acid and an isomer while all the other fatty acids were successfully separated by varying retention times and mass-to-charge ratios. For identification and separation of the isomer a derivatization method was evaluated. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.015DOI Listing

Triptycene-based stationary phases for gas chromatographic separations of positional isomers.

J Chromatogr A 2019 Apr 9. Epub 2019 Apr 9.

Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering and Analysis & Testing Center, Beijing Institute of Technology, Beijing, 100081, China. Electronic address:

This work presents the investigation of two triptycene-based materials (TP-3OB and TP-3Im) as the stationary phases for gas chromatographic (GC) separations. The TP-3OB and TP-3Im capillary columns fabricated by static coating exhibited column efficiency of 3000-3500 plates/m for n-dodecane at 120 °C. Also, their McReynolds constants and Abraham system constants were determined to characterize their polarity and molecular interactions with analytes. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.018DOI Listing
April 2019
2 Reads

Synthesis and characterization of polyamide-graphene oxide-polypyrrole electrospun nanofibers for spin-column micro solid phase extraction of parabens in milk samples.

J Chromatogr A 2019 Apr 8. Epub 2019 Apr 8.

Department of Chemistry, Tarbiat Modares University, Tehran, Iran.

In the present study, an electrospun composite of polyamide-graphene oxide-polypyrrole was synthesized. The characterization of the synthesized material was accomplished using field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FT-IR). FESEM images showed uniform and beadles nanofibers. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S00219673193036
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http://dx.doi.org/10.1016/j.chroma.2019.04.014DOI Listing
April 2019
3 Reads

In-situ derivatization and headspace solid-phase microextraction for gas chromatography-mass spectrometry analysis of alkyl methylphosphonic acids following solid-phase extraction using thin film.

J Chromatogr A 2019 Apr 8. Epub 2019 Apr 8.

Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon, 34141, South Korea. Electronic address:

A headspace solid-phase microextraction (HS-SPME) method, involving solid-phase extraction and in-situ derivatization using polymeric thin film, was developed for the gas chromatography-mass spectrometry (GC-MS) analysis of the degradation products of nerve agents. The solid-phase extraction (SPE) was performed using poly([2-(Methacryloyloxy)ethyl]trimethylammonium chloride) film on a gold plate prepared via surface-initiated polymerization. The extracted analytes were directly derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) on the plate. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.010DOI Listing

Two novel extraction chromatographic resins containing benzene-centered tripodal diglycolamide ligands: Actinide uptake, kinetic modeling and isotherm studies.

J Chromatogr A 2019 Mar 31. Epub 2019 Mar 31.

Laboratory of Molecular Nanofabrication, MESA(+)Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede, the Netherlands.

Two novel extraction chromatographic resins (EC), termed as RL-1 and RL-2, were prepared by impregnating two benzene-centered tripodal iglycolamide ligands (Bz-T-DGA) containing different spacer groups where the ligands are termed as L-1 and L-2, respectively. They were employed for the uptake of actinide and fission product ions, viz. Am, Eu, UO, Np, Pu, Sr, and Cs, from acidic feeds. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.067DOI Listing

Improved oil spill dispersant monitoring in seawater using dual tracers: Dioctyl and monoctyl sulfosuccinates sourced from corexit EC9500A.

J Chromatogr A 2019 Apr 7. Epub 2019 Apr 7.

Pacific and Yukon Laboratory for Environmental Testing, Science and Technology Branch, Pacific Environmental Science Centre, Environment & Climate Change Canada, North Vancouver, British Columbia, Canada. Electronic address:

A high resolution mass spectrometry method was developed for the environmental impact monitoring of oil spill dispersants. Previously reported instability of dioctyl sulfosuccinate (DOSS) dispersant tracer was addressed by the new procedure. The method monitors both DOSS and its degradation product, monooctyl sulfosuccinate (MOSS), by liquid chromatography time-of-flight mass spectrometry. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.049DOI Listing
April 2019
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Development of an on-line analytical platform to screen haptens in shuxuening injection based on high-performance liquid chromatography coupled with ion-trap multistage mass spectrometry and human serum albumin fluorescence detection.

J Chromatogr A 2019 Apr 8. Epub 2019 Apr 8.

Department of Natural Medicines, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China. Electronic address:

Shuxuening injection (SXNI), one of the traditional Chinese medicine injections (TCMI), is widely used for the treatment of cardiovascular diseases in the clinic. However, its allergic reactions have impeded the clinical applications of SXNI, such adverse reactions have not been well understood due to the lack of methods for detecting haptens. In this study, a high-performance liquid chromatography-diode-array detector-multi-stage mass spectrometry-human serum albumin-fluorescence detector (HPLC-DAD-MS-HSA-FLD) system was established to identify and screen haptens for the first time. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.011DOI Listing
April 2019
4 Reads

Qualitative evaluation of high pH mass spectrometry-compatible reversed phase liquid chromatography for altered selectivity in separations of intact proteins.

J Chromatogr A 2019 Apr 4. Epub 2019 Apr 4.

Department of Chemistry & Biochemistry, The University of Texas Arlington, Arlington, TX, USA. Electronic address:

Intact proteins are increasingly being recognized as potential biomarkers and biotherapeutic agents for cancer and other serious diseases. Low pH reversed phase plays an important role in both single and multidimensional protein separations for resolving complex protein samples prior to mass spectrometric detection. In this work, we evaluated the use of high pH reversed phase liquid chromatography as an alternative chromatographic separation to gain different selectivity while maintaining the high resolving power and MS compatibility of reversed phase separations. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.004DOI Listing

A pH-stable, crosslinked stationary phase based on the thiol-yne reaction.

J Chromatogr A 2019 Mar 29. Epub 2019 Mar 29.

University of Pittsburgh, Chevron Science Center, 219 Parkman Avenue, Pittsburgh, PA 15260, United States. Electronic address:

Stationary phases that can withstand extremes of pH and temperature are needed to allow a single column to accommodate a wider set of solutes and separation criteria. We used a simple multi-step process using the thiol-yne reaction following the modification of the silica surface with a thiol-containing silane. The monomers 1,4-diethynylbenzene (DEB) and 1,6-hexanedithiol were used to create a crosslinked thiol-yne (CTY) stationary phase along the surface of the thiol functionalized silica. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.058DOI Listing

Evaluating the applicability of a two-dimensional liquid chromatography system for a pesticide multi-screening method.

J Chromatogr A 2019 Apr 3. Epub 2019 Apr 3.

Federal Office of Consumer Protection and Food Safety, Mauerstraße 39-42, 10117 Berlin, Germany.

In this study, a fully automated two-dimensional liquid chromatography system was evaluated for pesticide analysis. The first dimension was a hydrophilic interaction liquid chromatography column for matrix separation. The analytes were collected on a trap column and transferred to the second dimension with a reversed phase column. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.003DOI Listing

Kinetic models of migration of melamine and formaldehyde from melamine kitchenware with data of liquid chromatography.

J Chromatogr A 2019 Apr 4. Epub 2019 Apr 4.

Department of Chemistry, Faculty of Sciences, Universidad de Burgos, Plaza Misael Bañuelos s/n, 09001 Burgos, Spain. Electronic address:

European legislation has established a specific migration limit (SML) of 15 mg kg for formaldehyde and 2.5 mg kg for melamine. Formaldehyde resins are used in the manufacture of melamine kitchenware. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.006DOI Listing
April 2019
8 Reads

Quantitative structure-retention relationship for chromatographic behaviour of anthraquinone derivatives through considering organic modifier features in micellar liquid chromatography.

J Chromatogr A 2019 Mar 30. Epub 2019 Mar 30.

Professor Massoumi Laboratory, Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran.

A simple and informative quantitative structure-retention relationship (QSRR) model has been introduced for prediction of retention times in some anthraquinone derivatives using reversed-phase micellar liquid chromatography (MLC) technique. In the developed multiple linear regression model, the structural descriptors of analytes as well as the empirical parameters of organic modifiers in the applied MLC systems have been considered. Retention times of 77 chromatographic samples (16 anthraquinones were evaluated by using 6 different organic modifiers) were experimentally determined and utilized as the independent variables of the QSRR model. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.063DOI Listing

Determination of volatile non intentionally added substances coming from a starch-based biopolymer intended for food contact by different gas chromatography-mass spectrometry approaches.

J Chromatogr A 2019 Apr 4. Epub 2019 Apr 4.

Waters Corporation, Wilmslow, SK9 4AX, United Kingdom.

The rapid growth of polymer technology in the field of food contact materials (FCMs) needs to be supported by continuous improvement in material testing, in order to ensure the safety of foodstuff. In this work, a range of different starch-based biopolymer samples, in the shape of pellets and retail samples (cups and dishes) were studied. The optimized extraction process was performed on three different pellet shapes: pellets with no modification (spherical), pellets shattered under high pressure (lentils), and pellets cryogenically ground (powder). Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.007DOI Listing
April 2019
4 Reads

The application of the supported liquid membrane and molecularly imprinted polymers as solid acceptor phase for selective extraction of biochanin A from urine.

J Chromatogr A 2019 Apr 4. Epub 2019 Apr 4.

Departamento de Medio Ambiente, INIA, Carretera de A Coruña km 7.5, 28240, Madrid, Spain.

An efficient sample clean-up and preconcentration procedure for phytoestrogens analysis in urine has been developed. It was based on a combination of solid phase extraction with hollow-fiber supported liquid membrane and molecularly imprinted beads (MIPs-HF-SLM-SPE). The molecularly imprinted polymers (MIPs) were synthesized by precipitation polymerization technique with biochanin A (BCA) as a template, giving narrowly dispersed microspheres with a regular shape. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.005DOI Listing

Comparison of high-performance thin-layer with overpressured layer chromatography combined with direct bioautography and direct analysis in real time mass spectrometry for tansy root.

J Chromatogr A 2019 Apr 1. Epub 2019 Apr 1.

Justus Liebig University Giessen, Institute of Nutritional Science, Chair of Food Science, and Interdisciplinary Research Center (IFZ), Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.

Bioactive polyacetylenes in tansy (Tanacetum vulgare L.) root extract were separated by overpressured layer chromatography (OPLC) with better resolutions than achievable by capillary flow high-performance thin-layer chromatography (HPTLC). OPLC enabled a longer development distance in a shorter time (16 cm, 7 min) in comparison to conventional HPTLC (7 cm, 16 min). Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.068DOI Listing
April 2019
4 Reads

A low-cost, open-source digital stripchart recorder for chromatographic detectors using a Raspberry Pi.

J Chromatogr A 2019 Apr 1. Epub 2019 Apr 1.

Department of Chemistry & Biochemistry, Rowan University, Glassboro, NJ, United States. Electronic address:

One of the most critical aspects of chromatographic analysis is effective data acquisition and processing. Typical approaches include software platforms designed for specific instruments or commercial data acquisition hardware boards, both of which require expensive licenses to use and operate. To increase the access and affordability of chromatographic data acquisition, especially for systems in which software control has become obsolete or must be written in-house, an open-source digital stripchart recorder has been developed. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.070DOI Listing

Effect of flow behavior in extra-column volumes on the retention pattern of proteins in a small column.

J Chromatogr A 2019 Apr 2. Epub 2019 Apr 2.

Department of Chemical and Process Engineering, Powstańców Warszawy Ave. 6, 35-959, Rzeszów, Poland. Electronic address:

Experimental and theoretical analysis of deformation of band profiles in extra-column volumes (ECV) was performed, and its influence on the retention pattern of proteins in a small chromatographic column was quantified. Several macromolecule and small-molecule compounds, and their mixtures were eluted from a chromatographic system in the absence and presence of the column. The peak deformation in ECV was attributed to non-uniform velocity distribution in the radial direction in connecting capillaries. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.060DOI Listing

Simultaneous authentication of species identity and geographical origin of shrimps: Untargeted metabolomics to recurrent biomarker ions.

J Chromatogr A 2019 Apr 3. Epub 2019 Apr 3.

Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, United Kingdom.

Mandatory disclosure of the species identity, production method, and geographical origin are embedded in the regulations and traceability systems, governing international seafood trade. A high-resolution mass spectrometry-based metabolomics approach could simultaneously authenticate the species identity and geographical origin of commercially important shrimps. The highly innovative approach spared the need for multiple testing methods which are in routine use currently. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.04.001DOI Listing
April 2019
7 Reads

Calixarene and ionic liquid assisted matrix solid-phase dispersion microextraction of organic acids from fruit.

J Chromatogr A 2019 Mar 30. Epub 2019 Mar 30.

College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250355, China. Electronic address:

A rapid and effective method was successfully established for the extraction and determination of chlorogenic acid, protocatechuic acid, malic acid, caffeic acid and gallic acid in fruit (chaenomeles speciosa) via matrix solid-phase dispersion (MSPD) microextraction combined with ultra-high performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF/MS). Several major extraction parameters were investigated and optimized, such as the type of sorbent, the amount of sorbent, the grinding time, the type and concentration of the eluting solvent. The optimal extraction conditions were obtained by using 20 mg of calix[8]arene as dispersing adsorbent, selecting 60 s as the appropriate grinding time and applying 250 mM of 1-dodecyl-3-methylimidazolium bromide as eluent solvent. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.055DOI Listing
March 2019
1 Read

Charged aerosol detector HPLC as a characterization and quantification application of biopharmaceutically relevant polysialic acid from E. coli K1.

J Chromatogr A 2019 Apr 1. Epub 2019 Apr 1.

Institute of Technical Chemistry, Leibniz University Hannover, Hannover, Germany.

Polysialic acid (polySia) is widely investigated in various biopharmaceutical applications (e.g. treatment of inflammatory neurodegenerative diseases), whereby a certain polySia chain length with an average degree of polymerization 20 (polySia avDP20) shows most promising effects. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.069DOI Listing

Preparation of flavone di-C-glycoside isomers from Jian-Gu injection (Premna fulva Craib.) using recycling counter-current chromatography.

J Chromatogr A 2019 Mar 21. Epub 2019 Mar 21.

Guangxi Key Laboratory of Functional Phytochemicals Research and Utilization, Institute of Botany, Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences, Guilin, 541006, China. Electronic address:

Jian-Gu Injection (JGI, Premna fulva Craib) has been demonstrated to be effective in the clinical treatment of bone hyperplasia. However, an effective purification method of the JGI flavone C-glycosides as reference materials is not available. The present work developed a recycling counter-current chromatography approach to prepare these materials in high quality. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.030DOI Listing

Room temperature and sensitive determination of haloanisoles in wine using vacuum-assisted headspace solid-phase microextraction.

J Chromatogr A 2019 Mar 23. Epub 2019 Mar 23.

Laboratory of Aquatic Chemistry, School of Environmental Engineering, Polytechnioupolis, Technical University of Crete, GR-73100, Chania, Crete, Greece. Electronic address:

Headspace solid-phase microextraction (HSSPME) is a widespread technique used to extract trace amounts of haloanisoles from wine samples. A major challenge to overcome is the high ethanol content in wines that affects the solubilities of haloanisoles and reduces their headspace abundance. To overcome this obstacle and meet sensitivity requirements, reported HSSPME procedures typically suggest heating the wine samples and/or sampling for extended times. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.047DOI Listing
March 2019
1 Read

Determining gradient conditions for peptide purification in RPLC with machine-learning-based retention time predictions.

J Chromatogr A 2019 Mar 29. Epub 2019 Mar 29.

Department of Engineering and Chemical Sciences, Karlstad University, SE-651 88 Karlstad, Sweden. Electronic address:

A strategy for determining a suitable solvent gradient in silico in preparative peptide separations is presented. The strategy utilizes a machine-learning-based method, called ELUDE, for peptide retention time predictions based on the amino acid sequences of the peptides. A suitable gradient is calculated according to linear solvent strength theory by predicting the retention times of the peptides being purified at three different gradient slopes. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.043DOI Listing
March 2019
1 Read

Determination of microcystins, nodularin, anatoxin-a, cylindrospermopsin, and saxitoxin in water and fish tissue using isotope dilution liquid chromatography tandem mass spectrometry.

J Chromatogr A 2019 Apr 1. Epub 2019 Apr 1.

Department of Environmental Science, Center for Reservoir and Aquatic Systems Research, Baylor University, Waco, TX, 76798, USA; Institute of Biomedical Studies, Baylor University, Waco, TX, 76798, USA. Electronic address:

Cyanobacteria can form dense blooms under specific environmental conditions, and some species produce secondary metabolites known as cyanotoxins, which present significant risks to public health and the environment. Identifying toxins produced by cyanobacteria present in surface water and fish is critical to ensuring high quality food and water for consumption, and protectionn of recreational uses. Current analytical screening methods typically focus on one class of cyanotoxins in a single matrix and rarely include saxitoxin. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.066DOI Listing

An efficient headspace gas chromatographic technique for determining humic acid content in fertilizer.

J Chromatogr A 2019 Mar 18. Epub 2019 Mar 18.

Health Supervision Bureau of Liaoning Province, Shenyang, China.

A fast, convenient and commercially available approach for analyzing humic acid content in fertilizer using headspace gas chromatography (HS-GC) is presented in this paper. Humic acid is converted into carbon dioxide based on the oxidation of humic acid in strong acidic medium and can be measured via automatic HS-GC. Conditions for the alkaline extraction and the humic acid oxidation process are also optimized. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.027DOI Listing

β-Cyclodextrin-copper (II) complex as chiral selector in capillary electrophoresis for the enantioseparation of β-blockers.

J Chromatogr A 2019 Mar 14. Epub 2019 Mar 14.

Australian Centre for Research on Separation Science, School of Natural Sciences-Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia. Electronic address:

The Copper (II) complex of β-cyclodextrin (β-CD), β-CDCu, was prepared and used as a chiral selector for the enantioseparation of 11 β-blockers by capillary electrophoresis. Resolution for 10 pairs of enantiomers was greater than 1.9 and for the four stereoisomers of labetalol (with two chiral centers), the closest two peaks had a resolution of 1. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.019DOI Listing
March 2019
4.169 Impact Factor

Task-specific solid-phase microextraction based on ionic liquid/polyhedral oligomeric silsesquioxane hybrid coating for sensitive analysis of polycyclic aromatic hydrocarbons by gas chromatography-mass spectrometry.

J Chromatogr A 2019 Mar 29. Epub 2019 Mar 29.

Key Laboratory for Analytical Science of Food Safety and Biology (Ministry of Education & Fujian Province), PR China; College of Chemistry, Fuzhou University, Fuzhou, 350116, PR China. Electronic address:

A direct immersion solid-phase microextraction (DI-SPME) approach for gas chromatography-mass spectrometry (GC-MS) based on hybrid fiber coating of ionic liquid and polyhedral oligomeric silsesquioxane (POSS) is presented. To fabricate the task-specific coating for the enrichment of polycyclic aromatic hydrocarbons (PAHs), 1-butyl-3-vinylimidazolium bis[(trifluoromethyl)sulfonyl]imide (IL) and POSS were rapidly photoinitiated copolymerized within 5 min on a stainless steel fiber. The high efficient extraction of target analytes can be attributed to a combined result of multiple interactions including the strong CF⋯HC pseudohydrogen bonding, π-π stacking, hydrophobic force, and molecular sieve effect. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.062DOI Listing
March 2019
2 Reads

Streamlining the polishing step development process via physicochemical characterization of monoclonal antibody aggregates.

J Chromatogr A 2019 Mar 22. Epub 2019 Mar 22.

Biologics Process Development, Global Product Development and Supply, Bristol-Myers Squibb Company, Devens, MA, USA.

When developing purification processes for monoclonal antibodies (mAbs), ensuring the effective removal of high molecular weight (HMW) species is often challenging and labor intensive. In this work, we present a bottom-up characterization approach to achieve streamlined polishing step development as well as a more fundamental understanding of the protein of interest. Prior to physicochemical characterization, in-process HMW species of two IgG4 mAbs (mAb A and mAb B) were isolated via semi-preparative size exclusion chromatography (SEC). Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.044DOI Listing

Elucidation of metabolite isomers of Leonurus japonicus and Leonurus cardiaca using discriminating metabolite isomerism strategy based on ultra-high performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry.

J Chromatogr A 2019 Mar 28. Epub 2019 Mar 28.

National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, State Key Laboratory Breeding Base of Dao-di Herbs, Beijing, 100700, PR China. Electronic address:

The isomer structural discrimination is a significant challenge in metabolome analysis based on ultrahigh performance liquid chromatography tandem high-resolution mass spectrometry (UHPLC-HRMS). In this study, a new discriminating metabolite isomerism strategy is proposed to elucidate the metabolome, especially the isomers, of Leonurus japonicus and Leonurus cardiaca. This strategy consists of three steps. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.059DOI Listing

High separation efficiency of gold nanomaterials of different aspect ratio and size using capillary transient isotachophoresis.

J Chromatogr A 2019 Mar 25. Epub 2019 Mar 25.

National Institute of Standards and Technology, Material Measurement Laboratory - Chemical Sciences Division, 100 Bureau Drive, Gaithersburg, MD, 20899, USA.

Two modes of capillary electrophoresis (CE), capillary zone electrophoresis (CZE) and capillary transient isotachophoresis (ctITP), were compared for the detection and separation of spherical gold nanoparticles (AuNPs) and gold nanorods (AuNRs). The development of ctITP using two different leading ions is described. Overall, when compared to traditional capillary zone electrophoresis (CZE), ctITP resulted in improved peak shape and peak efficiency. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.054DOI Listing
March 2019
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Magnetic adsorbent based on mesoporous silica nanoparticles for magnetic solid phase extraction of pyrethroid pesticides in water samples.

J Chromatogr A 2019 Mar 25. Epub 2019 Mar 25.

Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, College of Chemistry and Materials Science, Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, China. Electronic address:

Mesoporous KIT-6-magnetite composite (FeO@SiO@KIT-6) was successfully prepared and characterized by transmission electron microscopy, scan electron microscopy, elemental mapping, energy dispersive X-ray spectrum, Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray powder diffraction, Brunauer Emmett Teller analysis and magnetic property analysis. It was then applied as adsorbent for magnetic solid phase extraction of fenpropathrin, lambda-cyhalothrin, S-fenvalerate and bifenthrin from water samples before analyzed by high performance liquid chromatography-ultraviolet detector. A few factors impacting extraction were studied. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.048DOI Listing
March 2019
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4.169 Impact Factor

Magnetic molecularly imprinted polymers doped with graphene oxide for the selective recognition and extraction of four flavonoids from Rhododendron species.

J Chromatogr A 2019 Mar 25. Epub 2019 Mar 25.

Lanzhou Institute of Animal Science and Veterinary Pharmaceutics, Chinese Academy of Agricultural Sciences, Lanzhou 730050, Gansu, China. Electronic address:

Herein, a novel magnetic molecularly imprinted polymer doped with reticular graphene oxide (FeO@SiO-GO@MIPs) was synthesized for the selective recognition and extraction of 4 flavonoids (farrerol, taxifolin, kaempferol, and hyperin) from Rhododendrons species. The FeO@SiO-GO@MIPs with lamellar membranes showed outstanding adsorption capacity. The 3D cavities complementary to the "shape" of farrerol were "imprinted" on the polymer framework after removal of farrerol template. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.053DOI Listing
March 2019
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Optimization of extraction solvents, solid phase extraction and decoupling for quantitation of free isoprenoid diphosphates in Haematococcus pluvialis by liquid chromatography with tandem mass spectrometry.

J Chromatogr A 2019 Mar 23. Epub 2019 Mar 23.

Shenzhen Public Platform of Screening & Application of Marine Microbial Resources, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China. Electronic address:

Isoprenoid diphosphates are important precursors actively participating in many downstream metabolisms; they are often in modified forms, e.g., protein-coupled or esterified form. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.051DOI Listing
March 2019
4.169 Impact Factor

Discussion: Automated filtration or really just solid phase extraction.

J Chromatogr A 2019 Mar 25. Epub 2019 Mar 25.

Territory Pathology, Department of Pathology, Alice Springs Hospital, 6 Gap Road, The Gap, Northern Territory 0870, Australia. Electronic address:

In this article, we discuss a recent publication by Casati et al. (2018) focusing on the sample preparation that is described for the analysis of phosphatidylethanols and whether or not their proposed method of 'automated filtration' and the advantages it brings is really just a standard solid phase extraction protocol. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S00219673193032
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http://dx.doi.org/10.1016/j.chroma.2019.03.052DOI Listing
March 2019
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Experimental and numerical study of band-broadening effects associated with analyte transfer in microfluidic devices for spatial two-dimensional liquid chromatography created by additive manufacturing.

J Chromatogr A 2019 Mar 22. Epub 2019 Mar 22.

Universiteit van Amsterdam, Van' t Hoff Institute for Molecular Sciences, Science Park 904, 1098 XH, Amsterdam, the Netherlands.

Conventional one-dimensional column-based liquid chromatographic (LC) systems do not offer sufficient separation power for the analysis of complex mixtures. Column-based comprehensive two-dimensional liquid chromatography offers a higher separation power, yet suffers from instrumental complexity and long analysis times. Spatial two-dimensional liquid chromatography can be considered as an alternative to column-based approaches. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.041DOI Listing
March 2019
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High performance thin-layer chromatography-mass spectrometry methods on diol stationary phase for the analyses of flavan-3-ols and proanthocyanidins in invasive Japanese knotweed.

J Chromatogr A 2019 Mar 23. Epub 2019 Mar 23.

Department of Food Chemistry, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. Electronic address:

We developed the first four HPTLC methods for the separation of proanthocyanidins according to degree of polymerization on HPTLC diol F plates. Acetonitrile, ethyl acetate, ethyl acetate-formic acid (9:0.1, v/v) and toluene-acetone-formic acid (3:6:1, v/v) were used as developing solvents and 4-dimethylaminocinnamaldehyde (DMACA) as the detection reagent. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.050DOI Listing

Ternary thiol-ene photopolymerization for facile preparation of ionic liquid-functionalized hybrid monolithic columns based on polyhedral oligomeric silsesquioxanes.

J Chromatogr A 2019 Mar 22. Epub 2019 Mar 22.

Key Laboratory for Analytical Science of Food Safety and Biology (Ministry of Education & Fujian Province), College of Chemistry, Fuzhou University, Fuzhou 350108, P.R. China. Electronic address:

A simple thiol-ene photopolymerization approach was developed for the rapid preparation of ionic liquid-functionalized hybrid monolithic column based on polyhedral oligomeric silsesquioxane (POSS). "One-pot" polymerization was realized in the UV-transparent fused-silica capillary by using octanethiol, 1-allyl-3-methylimidazolium hexafluorophosphate as functional monomers and methacryl-substituted POSS as a crosslinker. The thiol-vinyl-methacrylate ternary system uniquely exhibits a mixed step-chain growth polymerization regime that combining the thiol-ene reaction and free-radical reaction mechanisms, which provides a simple route to prepare novel POSS-based functionalized hybrid monoliths. Read More

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https://linkinghub.elsevier.com/retrieve/pii/S00219673193028
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http://dx.doi.org/10.1016/j.chroma.2019.03.032DOI Listing
March 2019
10 Reads

Silicon nanowire arrays for the preconcentration and separation of trace explosives vapors.

J Chromatogr A 2019 Mar 22. Epub 2019 Mar 22.

Chemistry Division, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States.

Silicon nanowire (SiNW) arrays are demonstrated as a suitable platform for the preconcentration of trace nitroaromatic compounds and subsequent desorption via Joule heating of the array. Arrays are fabricated from Si wafers containing an epitaxially grown layer of low conductivity intrinsic Si sandwiched between layers of high conductivity p-type Si. Passage of current through the nanowires results in nanowire temperatures in excess of 200 °C during heating of the arrays as verified by using the temperature-dependent shift of the Si Raman band at ˜520 cm. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.045DOI Listing
March 2019
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The use of alteration analysis in supercritical fluid chromatography to monitor changes in a series of chromatograms.

J Chromatogr A 2019 Mar 18. Epub 2019 Mar 18.

MTA-PTE Molecular Interactions in Separation Science Research Group, Ifjúság útja 6, H-7624 Pécs, Hungary; Department of Analytical and Environmental Chemistry and Szentágothai Research Center, University of Pécs, Ifjúság útja 6, H-7624 Pécs, Hungary; Institute of Bioanalysis, Medical School, University of Pécs, Szigeti út 12, H-7624 Pécs, Hungary. Electronic address:

Two-dimensional correlation analysis (2DCOR) is a unique chemometric method introduced in spectroscopy which became successful in a wide range of analytical fields. It was applied in chromatography as well but has not gained wide-spread popularity. In our previous work, we introduced an alternative method, Alteration Analysis (ALA), which is built upon the basic properties of 2DCOR, but it is fine-tuned for chromatographic applications and can be used on higher dimensional data sets as well. Read More

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http://dx.doi.org/10.1016/j.chroma.2019.03.033DOI Listing
March 2019
1 Read