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https://www.readbyqxmd.com/read/29350497/sensitive-and-rapid-determination-of-pyrethroids-in-human-blood-by-gas-chromatography-tandem-mass-spectrometry-with-ultrasound-assisted-dispersive-liquid-liquid-microextraction
#1
Xue Gao, Hao Guo, Junwei Wang, Qingbiao Zhao
In this study, a sensitive and fast procedure of ultrasonic-assisted dispersive liquid-liquid microextraction (UADLLME) coupled with gas chromatography tandem mass spectrometry (GC-MS/MS) for the determination of major pyrethroid pesticides (permethrin, tetramethrin, bifenthrin, fenvalerate, flucythrinate, fluvalinate, fenpropathrin, deltamethrin and cyhalothrin) in blood samples was developed. Response surface methodology (RSM) combined with Box-Behnken design (BBD) and ANOVA function were used to optimize key factors affecting the extraction efficiency of UADLLME procedure...
January 19, 2018: Drug Testing and Analysis
https://www.readbyqxmd.com/read/29349861/validated-uplc-ms-ms-method-for-quantification-of-seven-compounds-in-rat-plasma-and-tissues-application-to-pharmacokinetic-and-tissue-distribution-studies-in-rats-after-oral-administration-of-extract-of-eclipta-prostrata-l
#2
Guangyan Du, Lingling Fu, Jun Jia, Xu Pang, Haiyang Yu, Youcai Zhang, Guanwei Fan, Xiumei Gao, Lifeng Han
A rapid, sensitive and specific ultra high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) method was developed to investigate the pharmacokinetics and tissue distribution of Eclipta prostrata extract. Rats were orally administrated the 70% ethanol extract of E. prostrata, and their plasma as well as various organs were collected. The concentrations of seven main compounds, including ecliptasaponin IV, ecliptasaponin A, apigenin, 3'-hydroxybiochanin A, luteolin, luteolin-7-O-glucoside, and wedelolactone, were quantified by UPLC-MS/MS through multiple reactions monitoring (MRM) method...
January 19, 2018: Biomedical Chromatography: BMC
https://www.readbyqxmd.com/read/29342422/magnetic-mesoporous-molecularly-imprinted-polymers-based-on-surface-precipitation-polymerization-for-selective-enrichment-of-triclosan-and-triclocarban
#3
Xuemei Wang, Pengfei Huang, Xiaomin Ma, Xinzhen Du, Xiaoquan Lu
Novel magnetic mesoporous molecularly imprinted polymers (MMIPs) were prepared based on surface precipitation polymerization using Triclosan (TCS) as template and methacrylic acid as functional monomer. The synthesized MMIPs-TCS were applied to the adsorbent of magnetic solid-phase extraction (MSPE) coupled with HPLC for the enrichment and determination of TCS. The MMIPs-TCS were characterized by fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption transmission, and vibrating sample magnetometry...
January 10, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29338668/simultaneous-determination-of-afidopyropen-and-its-metabolite-in-vegetables-fruit-and-soil-using-uhplc-ms-ms
#4
Kaiying Chen, Xingang Liu, Xiaohu Wu, Fengshou Dong, Jun Xu, Yongquan Zheng
A new analytical method using the quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure for simultaneous determination of afidopyropen and its metabolite M440I007 residues in tomato, watermelon, pepper, cucumber, pear, grape, cabbage and soil samples was developed using ultra-high performance liquid chromatography coupled with tandem mass spectrometry. The target compound was determined in less than 5.0 min using an electrospray ionisation source in positive mode (ESI+). The limit of quantification was 1 μg kg-1 in different matrices...
January 17, 2018: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
https://www.readbyqxmd.com/read/29337671/spectrophotometric-method-for-simultaneous-determination-of-valsartan-and-substances-from-the-group-of-statins-in-binary-mixtures
#5
Mariusz Stolarczyk, Anna Apola, Anna Maślanka, Anna Kwiecień, Włodzimierz Opoka
Applicability of derivative spectrophotometry for the determination of valsartan in the presence of a substance from the group of statins was checked. The obtained results indicate that the proposed method may be effective by using appropriate derivatives: for valsartan and fluvastatin - D1, D2 and D3, for valsartan and pravastatin - D1 and D3, for valsartan and atorvastatin - D2 and D3. The method was characterized by high sensitivity and accuracy. Linearity was maintained in the following ranges: 9.28-32...
December 20, 2017: Acta Pharmaceutica
https://www.readbyqxmd.com/read/29332839/magnetic-solid-phase-extraction-based-on-magnetic-multiwalled-carbon-nanotubes-for-the-simultaneous-enantiomeric-analysis-of-five-%C3%AE-blockers-in-the-environmental-samples-by-chiral-liquid-chromatography-coupled-with-tandem-mass-spectrometry
#6
Zhaokun Wang, Xue Zhang, Shenmeng Jiang, Xingjie Guo
In this work, the magnetic multiwalled carbon nanotubes (Mag-MWCNTs) were prepared by self-assembly method and characterized by scanning electron microscopy, X-ray powder diffraction, energy dispersive X-ray and vibrating sample magnetometer. Then, these synthetic Mag-MWCNTs were used as sorbents to extract five β-blockers (atenolol, metoprolol, esmolol, pindolol and arotinolol) by magnetic solid-phase extraction. The target analytes adsorbed on Mag-MWCNTs were eluted and determined on a chiral α-acid glycoprotein column coupled with a triple quadrupole mass spectrometry...
April 1, 2018: Talanta
https://www.readbyqxmd.com/read/29332838/rapid-and-sensitive-tapered-capillary-microextraction-combined-to-on-line-sample-stacking-capillary-electrophoresis-for-extraction-and-quantification-of-two-beta-blockers-in-human-urine
#7
Shucheng Sun, Yujia Wang, Xin Liu, Rao Fu, Li Yang
A tapered-capillary microextraction (tCap-μEx) combining with field-amplified stacking (FASI) method for CE analysis was developed. The tCap-μEx method is based on the construction of a micro solid phase extraction (SPE) column by narrowing the end of a silica capillary from 530µm (inner diameter) to 20µm, enabling the packing of 45µm sorbent particles without a frit. Various parameters that may affect the microextraction and FASI-CE analysis have been investigated and optimized. This study shows that microextraction exhibits advantages of small sample and sorbent volumes (less than 200μL sample and 2μL sorbent) and fast extraction time of 6min...
April 1, 2018: Talanta
https://www.readbyqxmd.com/read/29332826/a-robust-and-extendable-sheath-flow-interface-with-minimal-dead-volume-for-coupling-ce-with-esi-ms
#8
Pan Fang, Jian-Zhang Pan, Qun Fang
In this paper, we describe a robust sheath flow-based CE-MS interface with minimal interface dead volume based on an extended pattern. A 20µm i.d. × 90µm o.d. fused-silica capillary with a chemically-etched thin-wall tip (30µm o.d.) was used as the separation capillary as well as electrospray emitter, and a 200µm i.d. × 375µm o.d. capillary with a tapered tip (40µm o.d.) was used as the sheath flow capillary. An extendable sheath-flow interface mode was adopted by decreasing the thickness of separation capillary tip and extending the separation capillary tip out from the sheath flow capillary tip, and allowing the sheath flow to be transferred to the separation capillary tip along its outer surface, forming a surface sheath flow to mix with sample flow at the separation capillary tip...
April 1, 2018: Talanta
https://www.readbyqxmd.com/read/29332823/a-combination-of-computational-experimental-study-on-metal-organic-frameworks-mil-53-al-as-sorbent-for-simultaneous-determination-of-estrogens-and-glucocorticoids-in-water-and-urine-samples-by-dispersive-micro-solid-phase-extraction-coupled-to-uplc-ms-ms
#9
Guihua Gao, Sijia Li, Shuo Li, Yudan Wang, Pan Zhao, Xiangyu Zhang, Xiaohong Hou
In this work, computational and experimental methods were used to study the adsorption of estrogens and glucocorticoids on metal-organic frameworks (MOFs). Computer-aided molecular simulation was applied to predict the adsorption of eight analytes on four MOFs (MIL-101(Cr), MIL-100(Fe), MIL-53(Al), and UiO-66(Zr)) by examining molecular interactions and calculating free binding energies. Subsequently, the four water-stable MOFs were synthesized and evaluated as adsorbents for the target hormones in aqueous solution...
April 1, 2018: Talanta
https://www.readbyqxmd.com/read/29332821/determination-of-pyrophosphate-and-sulfate-using-polyhexamethylene-guanidine-hydrochloride-stabilized-silver-nanoparticles
#10
E A Terenteva, V V Apyari, S G Dmitrienko, A V Garshev, P A Volkov, Yu A Zolotov
Positively charged polyhexamethylene guanidine hydrochloride-stabilized silver nanoparticles (PHMG-AgNPs) were prepared and applied as a colorimetric probe for single-step determination of pyrophosphate and sulfate. The approach is based on the nanoparticles aggregation leading to change in their absorption spectra and color of the solution. Due to both electrostatic and steric stabilization these nanoparticles show decreased sensitivity relatively to many common anions, which allows for simple and rapid direct single-step determination of pyrophosphate and sulfate...
April 1, 2018: Talanta
https://www.readbyqxmd.com/read/29332817/miniaturised-electrically-actuated-high-pressure-injection-valve-for-portable-capillary-liquid-chromatography
#11
Yan Li, Kirsten Pace, Pavel N Nesterenko, Brett Paull, Roger Stanley, Mirek Macka
A miniaturised high pressure 6-port injection valve has been designed and evaluated for its performance in order to facilitate the development of portable capillary high performance liquid chromatography (HPLC). The electrically actuated valve features a very small size (65 × 19 × 19mm) and light weight (33g), and therefore can be easily integrated in a miniaturised modular capillary LC system suited for portable field analysis. The internal volume of the injection valve was determined as 98 nL. The novel conical shape of the stator and rotor and the spring-loaded rotor performed well up to 32MPa (4641psi), the maximum operating pressure investigated...
April 1, 2018: Talanta
https://www.readbyqxmd.com/read/29332798/supported-carbon-dots-serve-as-high-performance-adsorbent-for-the-retention-of-trace-cadmium
#12
Yi-Kun Li, Ting Yang, Ming-Li Chen, Jian-Hua Wang
Carbon dots were prepared via a one-pot hydrothermal route, and a new solid-phase extraction (SPE) adsorbent was developed by immobilizing the carbon dots on the microcarrier cytopore, shortly termed as C-dots@cytopore. The C-dots@cytopore composites were characterized by means of FT-IR, SEM, XPS and fluorescence spectrometry. The performance of the composites for the adsorption of heavy metals was thoroughly evaluated by using cadmium as a model. The binding of cadmium on C-dots@cytopore fits Langmuir adsorption, and the adsorption dynamic follows pseudo-second-order adsorption kinetics model...
April 1, 2018: Talanta
https://www.readbyqxmd.com/read/29332276/variability-and-reliability-of-pop-concentrations-in-multiple-breast-milk-samples-collected-from-the-same-mothers
#13
Risa Kakimoto, Masayoshi Ichiba, Akiko Matsumoto, Kunihiko Nakai, Nozomi Tatsuta, Miyuki Iwai-Shimada, Momoko Ishiyama, Noriko Ryuda, Takashi Someya, Ieyasu Tokumoto, Daisuke Ueno
Risk assessment of infant using a realistic persistent organic pollutant (POP) exposure through breast milk is essential to devise future regulation of POPs. However, recent investigations have demonstrated that POP levels in breast milk collected from the same mother showed a wide range of variation daily and monthly. To estimate the appropriate sample size of breast milk from the same mother to obtain reliable POP concentrations, breast milk samples were collected from five mothers living in Japan from 2006 to 2012...
January 13, 2018: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29331820/using-vibrational-molecular-spectroscopy-to-reveal-association-of-steam-flaking-induced-carbohydrates-molecular-structural-changes-with-grain-fractionation-biodigestion-and-biodegradation
#14
Ningning Xu, Jianxin Liu, Peiqiang Yu
Advanced vibrational molecular spectroscopy has been developed as a rapid and non-destructive tool to reveal intrinsic molecular structure conformation of biological tissues. However, this technique has not been used to systematically study flaking induced structure changes at a molecular level. The objective of this study was to use vibrational molecular spectroscopy to reveal association between steam flaking induced CHO molecular structural changes in relation to grain CHO fractionation, predicted CHO biodegradation and biodigestion in ruminant system...
January 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/29331796/determination-of-meropenem-in-endotracheal-tubes-by-in-tube-solid-phase-microextraction-coupled-to-capillary-liquid-chromatography-with-diode-array-detection
#15
L Hakobyan, J Pla Tolos, Y Moliner-Martinez, C Molins-Legua, Jesús Ruiz Ramos, M Gordon, Paula Ramirez-Galleymore, P Campins-Falco
Meropenem is a widely used antimicrobial for the treatment of infections associated with the use of invasive medical devices in intensive care unit patients. These treatments are not always effective, in fact, in-vitro studies have demonstrated the difficulty of antimicrobials to penetrate into the biofilm, however in-vivo studies of the effect of these compounds is a trend, mostly because of the complexity of pulmonary samples extracted from ETTs. Therefore, the objective of this study was to evaluate in-tube solid phase microextraction (in-tube SPME) coupled to capillary liquid chromatography (CapLC) with DAD to determine meropenem in ETTs in order to estimate the penetration capability into the biofilm...
January 8, 2018: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29331795/development-and-validation-of-an-uhplc-ms-ms-approach-for-simultaneous-quantification-of-five-bioactive-saponins-in-rat-plasma-application-to-a-comparative-pharmacokinetic-study-of-aqueous-extracts-of-raw-and-salt-processed-achyranthes-bidentata
#16
Yi Tao, Yingshan Du, Weidong Li, Baochang Cai
A simple, accurate and sensitive ultra high-performance liquid chromatography-tandem mass spectrometry approach was established for the simultaneous determination of β-ecdysterone, 25S-inokosterone, ginsenoside Ro, chikusetsusaponin IV and chikusetsusaponin IVa in rat plasma after oral administration of raw and salt-processed Achyranthes bidentata extract. The saponins were completely separated on a Waters BEH C18 UHPLC column by using acetonitrile/0.1% formic acid-water as mobile phases. The mass analysis was performed in a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) with negative scan mode...
January 9, 2018: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29331742/a-sensitive-and-selective-immunoaffinity-column-clean-up-coupled-to-uplc-ms-ms-for-determination-of-trace-methyl-3-quinoxaline-2-carboxylic-acid-in-animal-tissues
#17
Peipei Li, Xiaojun Zhang, Juanmei Zhang, Zhongyong Yan, Shuai Zhang, Si Chen, Yi Fang
This paper described a reliable and simple method for the selective determination of MQCA in animal tissues using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A highly targeted immunoaffinity column was used for sample purification after enzymatic hydrolysis. The purified extracts were analyzed by reversed-phase HPLC-MS/MS in positive ESI and multiple reaction monitoring mode. The calibration curves showed good linearity with correlation coefficient (r2) larger than 0...
January 3, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29329887/determination-of-n-glycans-by-high-performance-liquid-chromatography-using-6-aminoquinolyl-n-hydroxysuccinimidyl-carbamate-as-the-glycosylamine-labeling-reagent
#18
Yike Wu, Qiuyue Sha, Juan Du, Chang Wang, Liang Zhang, Bi-Feng Liu, Yawei Lin, Xin Liu
Robust, efficient identification and accurate quantification of N-glycans are of great significance in N-glycomics analysis. Here, a simple and rapid derivatization method, based on the combination of microwave-assisted deglycosylation and 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) labeling, was developed for the analysis of N-glycan by high performance liquid chromatography with fluorescence detection (HPLC-FLD). After optimizing various parameters affecting deglycosylation and derivatization by RNase B, the time for N-glycan labeling was shortened to 50 min with ∼10-fold enhancement in detection sensitivity comparing to conventional 2-aminobenzoic acid (2-AA) labeling method...
January 8, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29327113/storage-stability-study-of-porcine-hepatic-and-intestinal-cytochrome-p450-isoenzymes-by-use-of-a-newly-developed-and-fully-validated-highly-sensitive-hplc-ms-ms-method
#19
Wim Schelstraete, Mathias Devreese, Siska Croubels
Microsomes are an ideal medium to investigate cytochrome P450 (CYP450) enzyme-mediated drug metabolism. However, before microsomes are prepared, tissues can be stored for a long time. Studies about the stability of these enzymes in porcine hepatic and intestinal tissues upon storage are lacking. To be able to investigate CYP450 stability in microsomes prepared from these tissues, a highly sensitive and rapid HPLC-MS/MS method for the simultaneous determination of six CYP450 metabolites in incubation medium was developed and validated...
January 11, 2018: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29324714/determination-of-branched-chain-keto-acids-in-serum-and-muscles-using-high-performance-liquid-chromatography-quadrupole-time-of-flight-mass-spectrometry
#20
You Zhang, Bingjie Yin, Runxian Li, Pingli He
Branched-chain keto acids (BCKAs) are derivatives from the first step in the metabolism of branched-chain amino acids (BCAAs) and can provide important information on animal health and disease. Here, a simple, reliable and effective method was developed for the determination of three BCKAs (α-ketoisocaproate, α-keto-β-methylvalerate and α-ketoisovalerate) in serum and muscle samples using high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF/MS). The samples were extracted using methanol and separated on a 1...
January 11, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
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