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https://www.readbyqxmd.com/read/29143972/determination-of-tubuloside-b-by-lc-ms-ms-and-its-application-to-a-pharmacokinetic-study-in-rats
#1
Shenbao Yang, Ruiying Qu, Peilu Sun, Shan Xiong, Siyi Yan, Zhipeng Deng
Tubuloside B, a novel neuroprotective phenylethanoid, is a major active constituent of Cistanche tubulosa and Cistanche deserticola. A specific and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantification of tubuloside B in rat plasma. Sample preparation was conducted through a protein-precipitation extraction with methanol using tubuloside A as internal standard (IS). Chromatographic separation was achieved by using a Capcell Pak C18 column (2...
November 16, 2017: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/29142420/exploring-the-cytotoxic-potential-of-triterpenoids-enriched-fraction-of-bacopa-monnieri-by-implementing-in-vitro-in-vivo-and-in-silico-approaches
#2
Md Nasar Mallick, Washim Khan, Rabea Parveen, Sayeed Ahmad, Sadaf, Mohammad Zeeshan Najm, Istaq Ahmad, Syed Akhtar Husain
Background: Bacopa monnieri (BM) is a herbaceous plant traditionally used from time immemorial in Ayurvedic and folklore medicines. We hypothesized that the extract of the whole plant might contain numerous molecules with having antitumor activities that could be very effective in killing of human cancer cells. Objectives: This work investigated anticancer activity of bioactive fraction of BM. Materials and Methods: The hydroalcoholic extract of BM was fractionated with different solvent, namely, hexane, dichloromethane (DCM), acetone, methanol, and water...
October 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/29142392/quantitative-analysis-of-benzyl-isothiocyanate-in-salvadora-persica-extract-and-dental-care-herbal-formulations-using-reversed-phase-c18-high-performance-liquid-chromatography-method
#3
Maged Saad Abdel-Kader, Y T Kamal, Prawez Alam, Mohammed Hamed Alqarni, Ahmed Ibrahim Foudah
Context: Benzyl isothiocyanate is the active antimicrobial agent in Salvadora persica (siwak) widely used in Islamic countries for oral hygiene. Aims: Quantification of benzyl isothiocyanate in the ethanol extract of S. persica and some dental care herbal formulations labeled to contain siwak. Settings and Design: Simple and sensitive high-performance liquid chromatography method was designed. Subjects and Methods: Separation was achieved on reverse phase C18 (250 mm × 4...
October 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/29142388/analysis-of-free-amino-acids-in-different-extracts-of-orthosiphon-stamineus-leaves-by-high-performance-liquid-chromatography-combined-with-solid-phase-extraction
#4
Armaghan Shafaei, Nor Hidayah Ab Halim, Norhidayah Zakaria, Zhari Ismail
Background: Orthosiphon stamineus (OS) Benth is a medicinal plant and native in Southeast Asia. Previous studies have shown that OS leaves possess antioxidant, cytotoxic, diuretic, antihypertensive, and uricosuric effects. These beneficial effects have been attributed to the presence of primary and secondary metabolites such as polyphenols, amino acids, and flavonoids. Objective: To develop and validate an high-performance liquid chromatography (HPLC)-diode array detector (DAD) method combined with solid-phase extraction that involves precolumn derivatization with O-phthaladehyde for simultaneous analysis of free amino acids in OS leaves extracts...
October 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/29137709/simultaneous-detection-of-folic-acid-and-methotrexate-by-an-optical-sensor-based-on-molecularly-imprinted-polymers-on-dual-color-cdte-quantum-dots
#5
Ali A Ensafi, Parisa Nasr-Esfahani, B Rezaei
In this work, molecularly imprinted polymers (MIPs) were used on the surface of cadmium telluride quantum dots (CdTe QDs) for the simultaneous determination of folic acid (FA) and methotrexate (MTX). For this purpose, two different sizes of CdTe QDs with emission peaks in the yellow (QDY) and orange (QDO) spectral regions were initially synthesized and capped with MIPs. FA and MTX were used as templates for the synthesis of the two composites and designated as QDY-MIPs and QDO-MIPs, respectively. Fourier transform infrared spectroscopy, transmission electron microscopy, and fluorescence spectroscopy were employed to characterize the composites...
December 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29136927/enantioselective-determination-of-metconazole-in-multi-matrices-by-high-performance-liquid-chromatography
#6
Rujian He, Jun Fan, Qi Tan, Yecai Lai, Xiaodong Chen, Tai Wang, Ying Jiang, Yaomou Zhang, Weiguang Zhang
A reliable and effective HPLC analytical method has been developed to stereoselectively quantify metconazole in soil and flour matrices. Effects of polysaccharide chiral stationary phase, type and content of alcoholic modifier on separation of racemic metconazole have been discussed in detail. Resolution and quantitative determination of metconazole stereoisomers were performed by using an Enantiopak OD column, with the n-hexane-ethanol mixture (97:3, v/v) at the flow rate of 1.0mL/min. Then, extraction and cleanup procedures followed by the modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method were used for metconazole racemate in soil and flour matrices...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136917/one-step-direct-immunoassay-with-horseradish-peroxidase-as-antigen-for-studying-the-functionality-of-antibody-surfaces
#7
G Coussot, C Faye, A Le Postollec, M Dobrijevic
Antibody-coated surfaces (Ab surfaces) play a key role in bioanalytical tools developed for biosensors and diagnostics. Therefore, a high and well-defined functional activity of the Ab surface is required. The functional activity of the Ab surface depends on its available binding sites i.e. "the active sites" that are able to capture antigen (Ag). The number of active binding sites strongly depends on the immobilization strategy used to fix the Ab on the solid surface. Determination of layer thickness or surface topology are often used to characterize the Ab surfaces but there is no gold standard method for the study of the functionality of the Ab surfaces...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136910/low-cost-approach-to-increase-the-analysis-throughput-of-bar-adsorptive-microextraction-ba%C3%A2%C2%B5e-combined-with-environmentally-friendly-renewable-sorbent-phase-of-recycled-diatomaceous-earth
#8
Gabriela Mafra, Anderson Luiz Oenning, Adriana Neves Dias, Josias Merib, Dilma Budziak, Cristian Berto da Silveira, Eduardo Carasek
In this study, a novel apparatus for bar adsorptive microextraction (BAµE) using a voltage regulator was proposed as an alternative tool to improve the analysis throughput. In addition, recycled diatomaceous earth obtained as a brewery residue was employed as a biosorbent coating for the determination of methyl paraben, ethyl paraben, benzophenone and triclocarban in water samples by high-performance liquid chromatography-diode array detection (HPLC-DAD). The use of the extraction devices, comprised of floating adsorptive bars of 7...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136902/nitrone-formation-a-new-strategy-for-the-derivatization-of-aldehydes-and-its-application-on-the-determination-of-furfurals-in-foods-by-high-performance-liquid-chromatography-with-fluorescence-detection
#9
Ao Zhang, Zhaobing Guan, Hongwei Cai, Yiyong Huang, Yawei Lin, Xiaosong Hu
A nitrone formation method using a novel fluorescent reagent 4-hydroxylaminopropyl-7-methoxylcoumarin (HAMC) has been developed and applied for the determination of furfurals in foods using high performance liquid chromatography with fluorescence detection (HPLC-FLD). Furfurals samples were derivatized by HAMC in aqueous condition at room temperature in less than 30min and were subjected to direct HPLC-FLD analysis without extra purification or extraction. Compared with other conventional methods, nitrone formation method produced single chromatographic peak for each analyte, leading to simpler chromatograms and enhancing the overall sensitivity...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136901/biomarker-analysis-of-hemoglobin-adducts-of-acrylamide-and-glycidamide-enantiomers-for-mid-term-internal-exposure-assessment-by-isotope-dilution-ultra-high-performance-liquid-chromatography-tandem-mass-spectrometry
#10
Yu Zhang, Qiao Wang, Gong Zhang, Wei Jia, Yiping Ren, Yongning Wu
Hemoglobin (Hb) adducts of acrylamide (AA) and its oxidative metabolite glycidamide (GA) are important biomarkers for evaluating the mid-term exposure of acrylamide toxicity in vivo. Taking pentafluoro-2-methylphenyl isothiocyanates of N-(2-carbamoylethyl)valine (AAVal-PFPTH) and N-(2-carbamoyl-2-hydroxyethy)valine (GAVal-PFPTH) as target analytes, we developed an isotope dilution ultra-high performance liquid chromatograph tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of AA and GA hemoglobin (Hb) adducts under the electroscopy ionization negative (ESI‾) mode in the present work...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136887/flow-injection-analysis-flame-atomic-absorption-spectrometry-system-for-indirect-determination-of-sulfite-after-on-line-reduction-of-solid-phase-manganese-iv-dioxide-reactor
#11
Rouholah Zare-Dorabei, Shokoufeh Boroun, Meissam Noroozifar
A new and simple flow injection method followed by atomic absorption spectrometry was developed for indirect determination of sulfite. The proposed method is based on the oxidation of sulfite to sulphate ion using solid-phase manganese dioxide (30% W/W suspended on silica gel beads) reactor. MnO2 will be reduced to Mn(II) by sample injection in to the column under acidic carrier stream of HNO3 (pH 2) with flow rate of 3.5mLmin(-1) at room temperature. Absorption measurement of Mn(II) which is proportional to the concentration of sulfite in the sample was carried out by atomic absorption spectrometry...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136871/a-novel-task-specific-magnetic-polymeric-ionic-liquid-for-selective-preconcentration-of-potassium-in-oil-samples-using-centrifuge-less-dispersive-liquid-liquid-microextraction-technique-and-its-determination-by-flame-atomic-emission-spectroscopy
#12
Asadollah Beiraghi, Masood Shokri
In the present study a new centrifuge-less dispersive liquid-liquid microextraction technique based on application of a new task specific magnetic polymeric ionic liquid (TSMPIL) as a chelating and extraction solvent for selective preconcentration of trace amounts of potassium from oil samples is developed, for the first time. After extraction, the fine droplets of TSMPIL were transferred into an eppendorf tube and diluted to 500µL using distilled water. Then, the enriched analyte was determined by flame atomic emission spectroscopy (FAES)...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136867/deep-eutectic-solvent-based-advance-microextraction-method-for-determination-of-aluminum-in-water-and-food-samples-multivariate-study
#13
Abdul Haleem Panhwar, Mustafa Tuzen, Tasneem Gul Kazi
Preconcentration of aluminum Al(3+) was carried out by a novel deep eutectic solvent based ultrasound-assisted liquid phase microextraction (DES-UALPME) method. The deep eutectic solvents (DESs), a green solvent was first time used for enrichment and quantification of very low concentration of Al(3+) in water and food samples, prior to analysed by electrothermal atomic absorption spectrometry (ETAAS). In present method it was observed that % recovery of Al-8-hydroxyquinoline chelates efficiently extracted by DES solvent...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136846/determination-of-bisphenols-with-estrogenic-activity-in-plastic-packaged-baby-food-samples-using-solid-liquid-extraction-and-clean-up-with-dispersive-sorbents-followed-by-gas-chromatography-tandem-mass-spectrometry-analysis
#14
M T García-Córcoles, M Cipa, R Rodríguez-Gómez, A Rivas, F Olea-Serrano, J L Vílchez, A Zafra-Gómez
Bisphenols (BPs) are a family of chemicals with known endocrine disrupting activity. Bisphenol A (BPA) is the most representative prototype of this group of chemicals. Recently, the use of BPA, a prototype of endocrine disruptors, has been reduced and replaced with structural analogs due to its negative effects on both the environment and consumers. In this work, a new method is presented for the determination of seven BPs, with estrogenic activity in ready-to-eat plastic packaged baby foods. The procedure involves the isolation of the analytes using solid-liquid phase extraction with acetonitrile followed by a clean-up step with a mixture of dispersive-SPE sorbents (C18 and PSA) and magnesium sulphate, to reduce matrix effect from proteins, sugars and lipids...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136816/simultaneous-determination-of-tert-butylhydroquinone-propyl-gallate-and-butylated-hydroxyanisole-by-flow-injection-analysis-with-multiple-pulse-amperometric-detection
#15
Dmytro Bavol, Anastasios Economou, Jiri Zima, Jiri Barek, Hana Dejmkova
We report the first amperometric method for the simultaneous determination of tert-butylhydroquinone (tBHQ), propyl gallate (PG), and butylated hydroxyanisole (BHA) using flow injection analysis coupled to multiple-pulse amperometry. A sequence of potential pulses was selected in order to detect tBHQ, PG, and BHA separately in a single injection step at a glassy carbon electrode without the need of a preliminary separation. A mixture of methanol and 0.040M Britton-Robinson buffer was used both as a carrier solution and for dilution of analyzed solutions before injection...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136814/polyaniline-dicationic-ionic-liquid-coated-with-magnetic-nanoparticles-composite-for-magnetic-solid-phase-extraction-of-polycyclic-aromatic-hydrocarbons-in-environmental-samples
#16
Mohamad Shariff Shahriman, Muggundha Raoov Ramachandran, Nur Nadhirah Mohamad Zain, Sharifah Mohamad, Ninie Suhana Abdul Manan, Suhaila Mohd Yaman
In this present study, magnetic nanoparticles (MNPs) nanocomposites modified with polyaniline (PANI) coated newly synthesised dicationic ionic liquid (DICAT) forming MNP-PANI-DICAT were successfully synthesised as new generation material for magnetic solid phase extraction (MSPE). MNP-PANI-DICAT was characterised by FT-IR NMR, CHN, BET, SEM, TEM, and VSM techniques and the results were compared with MNP-PANI and native MNP. This new material was applied as a magnetic adsorbent for the pre-concentration and separation of polycyclic aromatic hydrocarbons (PAHs) due to the π-π interaction between polyaniline shell and dicationic ionic liquid (DICAT) with PAHs compounds...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136552/development-and-validation-of-modified-quechers-method-coupled-with-lc-ms-ms-for-simultaneous-determination-of-cymiazole-fipronil-coumaphos-fluvalinate-amitraz-and-its-metabolite-in-various-types-of-honey-and-royal-jelly
#17
Weijia Zheng, Jin-A Park, A M Abd El-Aty, Seong-Kwan Kim, Sang-Hyun Cho, Jeong-Min Choi, Hee Yi, Soo-Min Cho, Amer Ramadan, Ji Hoon Jeong, Jae-Han Shim, Ho-Chul Shin
Over the past few decades, honey products have been polluted by different contaminants, such as pesticides, which are widely applied in agriculture. In this work, a modified EN - quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method was developed for the simultaneous quantification of pesticide residues, including cymiazole, fipronil, coumaphos, fluvalinate, amitraz, and its metabolite 2,4-dimethylaniline (2,4-DMA), in four types of honey (acacia, wild, chestnut, and manuka) and royal jelly...
November 8, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29135931/analytical-parameters-of-an-amperometric-glucose-biosensor-for-fast-analysis-in-food-samples
#18
Margalida Artigues, Jordi Abellà, Sergi Colominas
Amperometric biosensors based on the use of glucose oxidase (GOx) are able to combine the robustness of electrochemical techniques with the specificity of biological recognition processes. However, very little information can be found in literature about the fundamental analytical parameters of these sensors. In this work, the analytical behavior of an amperometric biosensor based on the immobilization of GOx using a hydrogel (Chitosan) onto highly ordered titanium dioxide nanotube arrays (TiO₂NTAs) has been evaluated...
November 14, 2017: Sensors
https://www.readbyqxmd.com/read/29134807/a-high-time-resolution-optical-sensor-for-monitoring-atmospheric-nitrogen-dioxide
#19
Yong Tian, Xiaomin Zhang, Hui-Yan Shen, Aifeng Liu, Zongshan Zhao, Ming-Li Chen, Xuwei Chen
High-time resolution monitoring nitrogen dioxide (NO2) is of great importance for studying the formation mechanism of aerosol and improving air quality. Based on the Griess-Saltzman (GS) reaction, a portable NO2 optical sensor was developed by employing a porous polypropylene membrane tube (PPMT) integrated gas permeation collector and detector. The PPMT was filled with GS reagents and covered with a coaxial jacket tube for gas collection. Its two ends were respectively fixed with a yellowish green light emitting diode and a photodiode for optic signal reception...
November 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29132821/determination-of-the-content-of-alkyl-ketene-dimer-in-its-latex-by-an-ionic-liquid-assisted-headspace-gas-chromatography
#20
Ning Yan, Xiao-Fang Wan, Xin-Sheng Chai, Run-Quan Chen, Chun-Xia Chen
This paper reports on an ionic-liquid assisted headspace gas chromatographic (HS-GC) for the determination of the content of alkyl ketene dimer (AKD) in its latex samples, in which the GC system was equipped with a thermal conductivity detector (TCD). The method was based on the AKD hydrolysis conducted in 1-butyl-3-methylimidazolium chloride (ionic-liquid) added medium at 100°C for 10min in a closed headspace sample vial, and the measured CO2 (the resulting product of the hydrolysis) by HS-GC. The results showed that the present method has a good measurement precision (RSD <2...
November 7, 2017: Journal of Chromatography. A
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