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Journal of Chromatography. A

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https://www.readbyqxmd.com/read/28648257/a-capillary-micellar-electrokinetic-chromatography-method-for-the-stereoselective-quantitation-of-bioallethrin-in-biotic-and-abiotic-samples
#1
Mª Ángeles García, Nuria Menéndez-López, Karina Boltes, María Castro-Puyana, Mª Luisa Marina
A capillary micellar electrokinetic chromatography (MEKC) method was developed enabling the stereoselective separation of the insecticide bioallethrin. The use of sodium deoxycholate bile salt and acetyl-β-cyclodextrin (acetyl-β-CD) made possible the separation of bioallethrin stereoisomers with a high enantioresolution (7.4) in a short analysis time (6.5min). The analytical characteristics of the developed method were evaluated in terms of linearity, accuracy, precision, and limits of detection (LOD) and quantitation (LOQ) showing a good performance for the quantitation of bioallethrin stereoisomers with LODs of 0...
June 19, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28647148/monolithic-capillary-column-with-an-integrated-electrochemical-detector
#2
Martina Komendová, Radovan Metelka, Jiří Urban
The carbon fiber and silver microwire were used as working and pseudoreference electrode, respectively, and inserted into the ending of capillary to prepare monolithic capillary column with an integrated electrochemical detector. Prepared capillary devices offered stable and robust results with relative standard deviations of retention, resolution, and detection signal lower than 1.5, 5.5, and 5.0%, respectively. To further increase sensitivity of developed electrochemical microdetector, multiple pulse amperometry detection mode has been used...
June 19, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28648259/semisynthesis-and-spectral-characterization-of-5-methylpyranopelargonidin-and-4-methylfuropelargonidin-and-their-separation-and-detection-in-strawberry-fruit-wine
#3
Ondřej Kurka, Lukáš Kučera, Helena Pelantová, Marek Kuzma, Vladimír Havlíček, Petr Bednář
Condensation of anthocyanins and their aglycons with small organic molecules yields more stable natural dyes, e.g. pyranoanthocyanins arising spontaneously in various food products. Reaction of pelargonidin with acetone produces two isomeric anthocyanidin dyes - 5-methylpyranopelargonidin and 4-methylfuropelargonidin. A robust semipreparative liquid chromatographic method was developed to isolate both derivatives from a simple aged solution of pelargonidin in methanol: acetone: 37% aqueous hydrochloric acid (1:1:0...
June 17, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28645755/microwave-assisted-micellar-extraction-of-organic-and-inorganic-iodines-using-zwitterionic-surfactants
#4
Shu-Ling Wang, Ling Yi, Li-Hong Ye, Jun Cao, Li-Jing Du, Li-Qing Peng, Jing-Jing Xu, Qi-Dong Zhang
Zwitterionic surfactant, used as extractant in microwave-assisted extraction (MAE) was investigated for the first time to extract organic and inorganic iodines from kelp samples. Optimized conditions for the MAE were 200W of microwave irradiation power, 100°C of extraction temperature, 10min of microwave irradiation time, 1g of sample, and 20mL of solvent volume. Ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) was used for the quantitative and qualitative analyses of the iodines...
June 17, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28647147/capillary-electrophoresis-with-stationary-nanogel-zones-of-galactosidase-and-erythrina-cristagalli-lectin-for-the-determination-of-%C3%AE-1-3-linked-galactose-in-glycans
#5
Lisa A Holland, Srikanth Gattu, Cassandra L Crihfield, Lloyd Bwanali
A thermally responsive nanogel is used to create stationary zones of enzyme and lectin in a separation capillary. Once patterned in the capillary, analyte is driven through the zone, where it is converted to a specific product if an enzyme is used or captured if a lectin is used. These stationary zones are easily expelled after the analysis and then re-patterned in the capillary. The nanogel is compatible with enzymes and lectins and improves the stability of galactosidase, enabling more cost-effective use of biological reagents that provide insight into glycan structure...
June 16, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28647146/analysis-of-oxidised-heavy-paraffininc-products-by-high-temperature-comprehensive-two-dimensional-gas-chromatography
#6
H Potgieter, R Bekker, J Beigley, E Rohwer
Heavy petroleum fractions are produced during crude and synthetic crude oil refining processes and they need to be upgraded to useable products to increase their market value. Usually these fractions are upgraded to fuel products by hydrocracking, hydroisomerization and hydrogenation processes. These fractions are also upgraded to other high value commercial products like lubricant oils and waxes by distillation, hydrogenation, and oxidation and/or blending. Oxidation of hydrogenated heavy paraffinic fractions produces high value products that contain a variety of oxygenates and the characterization of these heavy oxygenates is very important for the control of oxidation processes...
June 16, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28645754/tunable-separations-based-on-a-molecular-size-effect-for-biomolecules-by-poly-ethylene-glycol-gel-based-capillary-electrophoresis
#7
Takuya Kubo, Naoki Nishimura, Hayato Furuta, Kei Kubota, Toyohiro Naito, Koji Otsuka
We report novel capillary gel electrophoresis (CGE) with poly(ethylene glycol) (PEG)-based hydrogels for the effective separations of biomolecules containing sugars and DNAs based on a molecular size effect. The gel capillaries were prepared in a fused silica capillary modified with 3-(trimethoxysilyl)propylmethacrylate using a variety of the PEG-based hydrogels. After the fundamental evaluations in CGE regarding the separation based on the molecular size effect depending on the crosslinking density, the optimized capillary provided the efficient separation of glucose ladder (G1 to G20)...
June 16, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28645753/multi-immunoreaction-based-dual-color-capillary-electrophoresis-for-enhanced-diagnostic-reliability-of-thyroid-gland-disease
#8
Nain Woo, Su-Kang Kim, Seong Ho Kang
Thyroid-stimulating hormone (TSH) secretion plays a critical role in regulating thyroid gland function and circulating thyroid hormones (i.e., thyroxine (T4) and triiodothyronine (T3)). A novel multi-immunoreaction-based dual-color capillary electrophoresis (CE) technique was investigated in this study to assess its reliability in diagnosing thyroid gland disease via simultaneous detection of TSH, T3, and T4 in a single run of CE. Compared to the conventional immunoreaction technique, multi-immunoreaction of biotinylated streptavidin antibodies increased the selectivity and sensitivity for individual hormones in human blood samples...
June 16, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28641833/glyoxal-and-methylglyoxal-as-urinary-markers-of-diabetes-determination-using-a-dispersive-liquid-liquid-microextraction-procedure-combined-with-gas-chromatography-mass-spectrometry
#9
M Pastor-Belda, A J Fernández-García, N Campillo, M D Pérez-Cárceles, M Motas, M Hernández-Córdoba, P Viñas
Glyoxal (GO) and methylglyoxal (MGO) are α-oxoaldehydes that can be used as urinary diabetes markers. In this study, their levels were measured using a sample preparation procedure based on salting-out assisted liquid-liquid extraction (SALLE) and dispersive liquid-liquid microextraction (DLLME) combined with gas chromatography-mass spectrometry (GC-MS). The effect of the derivatization reaction with 2,3-diaminonaphthalene, the addition of acetonitrile and sodium chloride to urine, and the DLLME step using the acetonitrile extract as dispersant solvent and carbon tetrachloride as extractant solvent were carefully optimized...
June 16, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28641832/ionic-liquid-based-vortex-assisted-liquid-liquid-microextraction-combined-with-liquid-chromatography-mass-spectrometry-for-the-determination-of-bisphenols-in-thermal-papers-with-the-aid-of-response-surface-methodology
#10
Ankita Asati, G N V Satyanarayana, Smita Panchal, Ravindra Singh Thakur, Nasreen G Ansari, Devendra K Patel
A sensitive, rapid and efficient ionic liquid-based vortex assisted liquid-liquid microextraction (IL-VALLME) with Liquid Chromatography Mass spectrometry (LC-MS/MS) method is proposed for the determination of bisphenols in thermal paper. Extraction factors were systematically optimized by response surface methodology. Experimental factors showing significant effects on the analytical responses were evaluated using design of experiment. The limit of detection for Bisphenol-A (BPA) and Bisphenol-S (BPS) in thermal paper were 1...
June 16, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28647144/simultaneous-determination-of-uv-filters-and-estrogens-in-aquatic-invertebrates-by-modified-quick-easy-cheap-effective-rugged-and-safe-extraction-and-liquid-chromatography-tandem-mass-spectrometry
#11
Ke He, Anne Timm, Lee Blaney
Ultraviolet-filters (UV-filters) and estrogens have attracted increased attention as contaminants of emerging concern (CECs) due to their widespread occurrence in the environment. Most of these CECs are hydrophobic and have the potential to accumulate in aquatic organisms. To date, co-analysis of UV-filters and estrogens has not been reported due, in part, to the complex environmental matrices. Here, a multi-residue method has been developed for simultaneous determination of five UV-filters and three estrogens in tissue from aquatic and marine organisms...
June 15, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28634069/high-through-put-liquid-chromatography-mass-spectrometry-requires-new-strategies-for-the-management-of-fluid-at-the-interface
#12
R Andrew Shalliker
No abstract text is available yet for this article.
June 15, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28629939/preparation-and-evaluation-of-400%C3%AE-m-i-d-polymer-based-hydrophilic-interaction-chromatography-monolithic-columns-with-high-column-efficiency
#13
Chusheng Liu, Haibin Li, Qiqin Wang, Jacques Crommen, Haibo Zhou, Zhengjin Jiang
The quest for higher column efficiency is one of the major research areas in polymer-based monolithic column fabrication. In this research, two novel polymer-based HILIC monolithic columns with 400μm I.D.×800μm O.D. were prepared based on the thermally initiated co-polymerization of N,N-dimethyl-N-(3-methacrylamidopropyl)-N-(3-sulfopropyl) ammonium betaine (SPP) and ethylene glycol dimethacrylate (EDMA) or N,N'-methylenebisacrylamide (MBA). In order to obtain a satisfactory performance in terms of column permeability, mechanical stability, efficiency and selectivity, the polymerization parameters were systematically optimized...
June 14, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28647145/a-new-peak-shape-analysis-approach-detection-and-quantitation-of-concurrent-fronting-tailing-and-their-effect-on-asymmetry-measurements
#14
M Farooq Wahab, Darshan C Patel, Daniel W Armstrong
Most peak shapes obtained in separation science depart from linearity for various reasons such as thermodynamic, kinetic, or flow based effects. An indication of the nature of asymmetry often helps in problem solving e.g. in column overloading, slurry packing, buffer mismatch, and extra-column band broadening. However, existing tests for symmetry/asymmetry only indicate the skewness in excess (tail or front) and not the presence of both. Two simple graphical approaches are presented to analyze peak shapes typically observed in gas, liquid, and supercritical fluid chromatography as well as capillary electrophoresis...
June 13, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28634067/magnetic-graphene-coated-inorganic-organic-hybrid-nanocomposite-for-enhanced-preconcentration-of-selected-pesticides-in-tomato-and-grape
#15
Hamid Rashidi Nodeh, Hassan Sereshti, Hamid Gaikani, Muhammad Afzal Kamboh, Zahra Afsharsaveh
The new magnetic graphene based hybrid silica-N-[3-(trimethoxysilyl)propyl]ethylenediamine (MG@SiO2-TMSPED) nanocomposite was synthesized via sol-gel process, and used as an effective adsorbent in magnetic solid phase extraction (MSPE) of three selected pesticides followed by gas chromatography micro-electron capture detection (GC-μECD). The adsorbent was characterized using Fourier transform-infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDXS) techniques...
June 13, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28629937/the-multi-mode-modulator-a-versatile-fluidic-device-for-two-dimensional-gas-chromatography
#16
John V Seeley, Nicolaas E Schimmel, Stacy K Seeley
A fluidic device called the multi-mode modulator (MMM) has been developed for use as a comprehensive two-dimensional gas chromatography (GC x GC) modulator. The MMM can be employed in a wide range of capacities including as a traditional heart-cutting device, a low duty cycle GC x GC modulator, and a full transfer GC x GC modulator. The MMM is capable of producing narrow component pulses (widths <50ms) while operating at flows compatible with high resolution chromatography. The sample path of modulated components is confined to the interior of a joining capillary...
June 13, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28629936/logit-log-evaluation-of-planar-yeast-estrogen-screens
#17
Dinah Schick, Wolfgang Schwack
Receptor assays like the yeast estrogen screen (YES) performed in microtiter plates normally provide dose-response curves with a sigmoidal shape in semi-log plots. Such sigmoidal plots can be linearized by the logit function resulting in logit-log plots, as mainly known for the evaluation of enzyme-linked immunosorbent assays and radioimmunoassays. Since the planar yeast estrogen screen (pYES) represents the transfer of the receptor assay YES to high-performance thin-layer chromatography (HPTLC), it was assumed to obtain sigmoidal shaped dose-response curves from the measured signals, which subsequently could be used to generate logit-log plots...
June 13, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28647149/argentation-gas-chromatography-revisited-separation-of-light-olefin-paraffin-mixtures-using-silver-based-ionic-liquid-stationary-phases
#18
He Nan, Cheng Zhang, Amrit Venkatesh, Aaron J Rossini, Jared L Anderson
Silver ion or argentation chromatography utilizes stationary phases containing silver ions for the separation of unsaturated compounds. In this study, a mixed-ligand silver-based ionic liquid (IL) was evaluated for the first time as a gas chromatographic (GC) stationary phase for the separation of light olefin/paraffin mixtures. The selectivity of the stationary phase toward olefins can be tuned by adjusting the ratio of silver ion and the mixed ligands. The maximum allowable operating temperature of these stationary phases was determined to be between 125°C and 150°C...
June 12, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28641835/rapid-purification-of-diastereoisomers-from-piper-kadsura-using-supercritical-fluid-chromatography-with-chiral-stationary-phases
#19
Huaxia Xin, Zhuoshun Dai, Jianfeng Cai, Yanxiong Ke, Hui Shi, Qing Fu, Yu Jin, Xinmiao Liang
Supercritical fluid chromatography (SFC) with chiral stationary phases (CSPs) is an advanced solution for the separation of achiral compounds in Piper kadsura. Analogues and stereoisomers are abundant in natural products, but there are obstacles in separation using conventional method. In this paper, four lignan diastereoisomers, (-)-Galbelgin, (-)-Ganschisandrin, Galgravin and (-)-Veraguensin, from Piper kadsura were separated and purified by chiral SFC. Purification strategy was designed, considering of the compound enrichment, sample purity and purification throughput...
June 12, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28634068/investigation-of-changes-in-endocannabinoids-and-n-acylethanolamides-in-biofluids-and-their-correlations-with-female-infertility
#20
Jun Ding, Xiao-Tong Luo, Yan-Ru Yao, Hua-Ming Xiao, Ming-Quan Guo
Female infertility is a worldwide medical problem, and the scarcity of infertility biomarkers has hindered the ability to launch preventive and therapeutic measures in a timely manner. Intriguingly, alterations in endocannabinoids (eCBs) and N-acylethanolamides (NAEs) have been observed in the biofluids of infertile females. Therefore, a hypothesis of using eCB and NAEs in biofluids as infertility biomarkers was proposed by several researchers; however, little evidence exists to verify the hypothesis. To investigate their correlations with female infertility, we developed a magnetic liquid microextraction-chemical derivatization (MLME-CD) method coupled with liquid chromatography-tandem mass spectrometry for the quantification of eCBs and NAEs in biofluids...
June 12, 2017: Journal of Chromatography. A
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