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High performance liquid chromatography

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https://www.readbyqxmd.com/read/28109074/determination-of-four-nadolol-stereoisomers-in-capsules-by-high-performance-liquid-chromatography-and-circular-dichroism
#1
Grazielle Prado Alexandre, Márcio Nardelli Wandermuren, Adriano Peron, Vanessa Franco Tavares, Denis Alexandre Ramalho Padeiro, Kelly Alessandra Sakiara, María Segunda Aurora-Prado, Anil Kumar Singh, Erika Rosa Maria Kedor-Hackmann, Maria Inês Rocha Miritello Santoro
Nadolol is a blocking agent with activity in β-adrenergic receptors. The objective of this research was to develop andvalidate an HPLC and circular dichroism method for the quantification of four nadolol stereoisomers in capsules. The HPLC method was validated using a Chiralcel OD column (250 × 4,6 mm, 10 μm). The mobile phase consisted of hexane-ethanol-diethylamine-acetic acid(86 + 14 + 0.3 + 0.3, v/v/v/v), with a flow rate of 0.7 mL/min and temperature of 25 ± 1°C and UV detection carried out at 220 nm...
January 21, 2017: Journal of AOAC International
https://www.readbyqxmd.com/read/28108753/release-of-free-amino-acids-upon-oxidation-of-peptides-and-proteins-by-hydroxyl-radicals
#2
Fobang Liu, Senchao Lai, Haijie Tong, Pascale S J Lakey, Manabu Shiraiwa, Michael G Weller, Ulrich Pöschl, Christopher J Kampf
Hydroxyl radical-induced oxidation of proteins and peptides can lead to the cleavage of the peptide, leading to a release of fragments. Here, we used high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and pre-column online ortho-phthalaldehyde (OPA) derivatization-based amino acid analysis by HPLC with diode array detection and fluorescence detection to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals. Bovine serum albumin (BSA), ovalbumin (OVA) as model proteins, and synthetic tripeptides (comprised of varying compositions of the amino acids Gly, Ala, Ser, and Met) were used for reactions with hydroxyl radicals, which were generated by the Fenton reaction of iron ions and hydrogen peroxide...
January 20, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28108381/metabolomic-study-of-the-intervention-effects-of-shuihonghuazi-formula-a-traditional-chinese-medicinal-formulae-on-hepatocellular-carcinoma-hcc-rats-using-performance-hplc-esi-tof-ms
#3
Yongrui Bao, Shuai Wang, Xinxin Yang, Li Tianjiao, Mingyue Xia, Xiansheng Meng
ETHNOPHARMACOLOGICAL RELEVANCE: Metabolomics is the comprehensive assessment of endogenous metabolites of a biological system in a holistic context, and its property consists with the global view of Traditional Chinese Medicine (TCM). Shuihonghuazi Formula (SHHZF) has been used for liver cancer early treatment in clinical for more than thirty years, but its mechanism remains unclear completely. This paper was designed to explore the therapeutic effects of SHHZF on liver cancer and its metabolomic characters...
January 17, 2017: Journal of Ethnopharmacology
https://www.readbyqxmd.com/read/28108196/homovanillic-acid-in-csf-of-mild-stage-parkinson-s-disease-patients-correlates-with-motor-impairment
#4
Alessandro Stefani, Mariangela Pierantozzi, Enrica Olivola, Salvatore Galati, Rocco Cerroni, Vincenza D'Angelo, Atticus H Hainsworth, Valentina Saviozzi, Ernesto Fedele, Claudio Liguori
In Parkinson's disease (PD), several efforts have been spent in order to find biochemical parameters able to identify the progression of the pathological processes at the basis of the disease. It is already known that advanced PD patients manifesting dyskinesia are featured by the high homovanillic acid (HVA)/dopamine (DA) ratio, suggesting the increased turnover of DA in these patients. Less clear is whether similar changes affect mild and moderate stages of the disease (between 1 and 2.5 of Hoehn & Yahr -H&Y- stage)...
January 18, 2017: Neurochemistry International
https://www.readbyqxmd.com/read/28108082/analysis-of-drugs-of-abuse-in-human-plasma-using-microextraction-by-packed-sorbents-and-ultra-high-performance-liquid-chromatography
#5
P Fernández, M González, M Regenjo, A M Ares, A M Fernández, R A Lorenzo, A M Carro
A miniaturized and simple method based on digitally programmed microextraction by packed sorbent (eVol(®)-MEPS) coupled to ultra-performance liquid chromatography (UPLC) has been developed for quantitative determination of three synthetic cathinones and seven conventional drugs of abuse and metabolites. The influence of several extraction parameters, such as washing and elution solvents were tested. In addition important variables affecting MEPS performance, namely sample volume, sorbent drying time, washing solvent volume, elution volume, number of extraction cycles, sorbent phase and pH, were evaluated using an asymmetrical screening design...
January 16, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28108079/preparation-and-evaluation-of-pillararene-bonded-silica-gel-stationary-phases-for-high-performance-liquid-chromatography
#6
Wenjie Zhao, Jianxiang Chu, Fuwei Xie, Qunpeng Duan, Lijun He, Shusheng Zhang
Pillararene bonded stationary phases for high performance liquid chromatography were prepared using 3-aminopropyltriethoxysilane as coupling reagent. The structure of the new materials was characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. The chromatographic performance and retention mechanism of the new stationary phases were evaluated in reversed-phase mode compared with C18 using different solute probes including Tanaka test solutes, polycyclic aromatic hydrocarbons, phenols and aromatic positional isomers...
December 11, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28107992/designing-of-ordered-two-dimensional-gold-nanoparticles-film-for-cocaine-detection-in-human-urine-using-surface-enhanced-raman-spectroscopy
#7
Juan Meng, Xianghu Tang, Binbin Zhou, Qiwen Xie, Liangbao Yang
A novel and rapid method to detect cocaine in human urine has been developed by using self-assembly ordered two dimensional (2D) gold nanoparticles (GNPs) film as surface-enhanced Raman spectroscopy (SERS) substrates. In order to obtain high sensitivity, uniformity, and reproducibility of SERS platform, quasi-spherical, uniform GNPs were firstly synthesis using seed growth method, in which the GNPs have been functionalized with CTAB to form orderly close-packed GNPs film as SERS substrate. Importantly, the high-performance GNPs on solid substrates can produce a high yield of sub-10-nm gaps which can generate gigantic signals enhancement for analytes adsorbed GNPs surface...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107974/analysis-of-bromophenols-in-various-aqueous-samples-using-solid-phase-extraction-followed-by-hplc-ms-ms
#8
Xiyuan Chi, Jiyan Liu, Miao Yu, Zhouqing Xie, Guibin Jiang
A reliable and effective method for simultaneous analysis of trace amount of bromophenols (BPs) in various aqueous samples was developed in this study. The aqueous samples must be acidified after sampling to prevent the fast degradation of bromophenols. Solid-phase extraction was chosen to extract and purify the water samples. High performance liquid chromatography coupled with tandem mass spectrometry with an electrospray ionization source (HPLC-ESI-MS/MS) was used for following identification and quantification...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107923/a-sensitive-and-rapid-uflc-apci-ms-ms-bioanalytical-method-for-quantification-of-endogenous-and-exogenous-vitamin-k1-isomers-in-human-plasma-development-validation-and-first-application-to-a-pharmacokinetic-study
#9
Nagaraj Kumar Nannapaneni, Sunil S Jalalpure, Rajendraprasad Muppavarapu, Sunil Kumar Sirigiri
Due to lack of suitable bioanalytical methods in previous literature, for simultaneous estimation of Vitamin K1 isomers, in compliance with the current regulatory expectation, we aimed to develop a sensitive and rapid method with UFLC-APCI-MS/MS (ultrafast liquid chromatography - tandem mass spectrometry) using human plasma. A simple and cost effective procedure was implemented with the combination of protein precipitation and liquid extraction, to isolate the targets from plasma sample, while achieving an insignificant matrix effects and high recovery (≥88...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107913/quantitative-structure-retention-relationship-model-for-the-determination-of-naratriptan-hydrochloride-and-its-impurities-based-on-artificial-neural-networks-coupled-with-genetic-algorithm
#10
Mikołaj Mizera, Anna Krause, Przemysław Zalewski, Robert Skibiński, Judyta Cielecka-Piontek
Mathematical modeling of Quantitative Structure - Property Relationships met great interest in fields of in silico drug design and more recently, pharmaceutical analysis. In our approach we proposed automated method of creation Quantitative Structure-Retention Relationship (QSRR) for analysis of triptans, selective serotonin 5-HT1 receptor agonists used for the treatment of acute headache. The method was created using hybrid machine learning approach, namely Genetic algorithm (GA) coupled with artificial neutral networks (ANN)...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107831/high-throughput-untargeted-screening-of-veterinary-drug-residues-and-metabolites-in-tilapia-using-high-resolution-orbitrap-mass-spectrometry
#11
Wei Jia, Xiaogang Chu, James Chang, Perry G Wang, Ying Chen, Feng Zhang
An analytical method was developed and validated for simultaneous analysis of one hundred and thirty-seven veterinary drug residues and metabolites from sixteen different classes in tilapia utilizing an improved fully non-targeted way of data acquisition with fragmentation. The automated on-line extraction procedure was achieved in a simple disposable pipet extraction. Ultrahigh-performance liquid chromatography and electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC Q-Orbitrap) was used for the separation and detection of all the analytes...
March 8, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28107829/high-throughput-online-solid-phase-extraction-ultra-high-performance-liquid-chromatography-tandem-mass-spectrometry-method-for-polyfluoroalkyl-phosphate-esters-perfluoroalkyl-phosphonates-and-other-perfluoroalkyl-substances-in-human-serum-plasma-and-whole-blood
#12
Somrutai Poothong, Elsa Lundanes, Cathrine Thomsen, Line Småstuen Haug
A rapid, sensitive and reliable method was developed for the determination of a broad range of poly- and perfluoroalkyl substances (PFASs) in various blood matrices (serum, plasma, and whole blood), and uses only 50 μL of sample material. The method consists of a rapid protein precipitation by methanol followed by high throughput online solid phase extraction (SPE), ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS), and negative electrospray ionization detection...
March 8, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28107624/tocilizumab-alendronate-conjugate-for-treatment-of-rheumatoid-arthritis
#13
Hwiwon Lee, Suk Ho Bhang, Jeong Ho Lee, Hyemin Kim, Sei Kwang Hahn
An autoimmune disease of rheumatoid arthritis (RA) causes severe inflammation on the synovial membrane, which results in the destruction of articular cartilage and bone. Here, Tocilizumab (TCZ) - Alendronate (ALD) conjugate is synthesized for the early intervention of RA. A humanized monoclonal antibody of TCZ shows an immunosuppressive effect, targeting interleukin-6 (IL-6) receptor in the RA pathogenesis. ALD is an anti-inflammatory bisphosphonate drug which can bind to the exposed bone surface. ALD is conjugated selectively to N-glycan on Fc region of TCZ using a chemical linker of 3-(2-pyridyldithio) propionyl hydrazide (PDPH) - poly(ethylene glycol) - N-hydroxysuccinimide (PDPH-PEG-NHS)...
January 20, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28107255/high-methotrexate-triglutamate-level-is-an-independent-predictor-of-adverse-effects-in-asian-indian-rheumatoid-arthritis-patients-a-preliminary-study
#14
Amit Sandhu, Varun Dhir, Archana Bhatnagar, Veena Dhawan, Jasbinder Kaur, Ankita Sood, Shankar Naidu, Shabeer Ahmad, Neelam Varma, Aman Sharma, Shefali Sharma
BACKGROUND: It is unclear whether erythrocyte methotrexate polyglutamate levels (MTX-glun) are associated with response or adverse effects to methotrexate in rheumatoid arthritis. This preliminary study evaluated their utility in Asian-Indian patients over 24 weeks. METHODS: Rheumatoid arthritis patients were started on oral methotrexate at a dose of 15 mg per week, which was escalated to 25 mg by 12 weeks and continued till 24 weeks. Erythrocyte (RBC) MTX-glu1 to MTX-glu5 levels (nmol/L RBC) were determined at 4, 8, 16, and 24 weeks by using reverse-phase high-performance liquid chromatography...
January 19, 2017: Therapeutic Drug Monitoring
https://www.readbyqxmd.com/read/28106519/subunit-mass-analysis-for-monitoring-antibody-oxidation
#15
Izabela Sokolowska, Jingjie Mo, Jia Dong, Michael J Lewis, Ping Hu
Methionine oxidation is a common posttranslational modification (PTM) of monoclonal antibodies (mAbs). Oxidation can reduce the in-vivo half-life, efficacy and stability of the product. Peptide mapping is commonly used to monitor the levels of oxidation, but this is a relatively time-consuming method. A high-throughput, automated subunit mass analysis method was developed to monitor antibody methionine oxidation. In this method, samples were treated with IdeS, EndoS and dithiothreitol to generate three individual IgG subunits (light chain, Fd' and single chain Fc)...
January 20, 2017: MAbs
https://www.readbyqxmd.com/read/28106339/determination-of-19-sulfonamides-residues-in-pork-samples-by-combining-quechers-with-dispersive-liquid-liquid-microextraction-followed-by-uhplc-ms-ms
#16
Xiaojing Li, Hong Yu, Rongfei Peng, Pingsheng Gan
A new simple and rapid pretreatment method for simultaneous determination of 19 sulfonamides in pork samples was developed through combining the QuEChERS method with dispersive liquid-liquid microextraction followed by ultra high performance liquid chromatography with tandem mass spectrometry. The sample preparation involves extraction/partitioning with QuEChERS method followed by dispersive liquid-liquid microextraction using tetrachloroethane as extractive solvent and the acetonitrile extract as dispersive solvent which obtained by QuEChERS...
January 20, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28106336/quantitative-analysis-combined-with-chromatographic-fingerprint-and-antioxidant-activities-for-the-comprehensive-evaluation-of-compound-danshen-tablets
#17
Jiao Chen, Jiayue Gao, Guoxiang Sun
The composition of traditional Chinese medicine is extremely complex, so it is difficult to ensure quality consistency. We took Compound Danshen Tablets as the object of the study, by using high-performance liquid chromatography to establish multi-wavelength fusion fingerprints. Characteristic fingerprints of 30 batches of samples were generated at four wavelengths and evaluated by systematic quantified fingerprint method. An on-line antioxidant determination method was used for the determination of the antioxidant components in Compound Danshen Tablets...
January 20, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28106330/separation-and-purification-of-two-taxanes-and-one-xylosyl-containing-taxane-from-taxus-wallichiana-zucc-a-comparison-between-high-speed-counter-current-chromatography-and-reversed-phase-flash-chromatography
#18
Junfei Tao, Rongwei Yan, Leilei Zhao, Dongmei Wang, Xinjun Xu
10-Deacetylbaccatin III, an important semi-synthetic precursor of paclitaxel and docetaxel, can be extracted from Taxus wallichiana Zucc.. A process for the isolation and purification of 10-deacetylbaccatin III (1), baccatin III (2) and 7β-xylosyl-10-deacetyltaxol (3) from the leaves and branches of Taxus wallichiana Zucc. via macroporous resin column chromatography combined with high-speed counter-current chromatography or reversed-phase flash chromatography was developed in this study. After fractionation by macroporous resin column chromatography, 80% methanol fraction was selected based on high-performance liquid chromatography and liquid chromatography with mass spectrometry qualitative analysis...
January 20, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28106326/new-oil-in-salt-liquid-phase-microextraction-on-permutite-for-the-extraction-and-concentration-of-alkaloids-in-coptis-chinensis
#19
Ping Gao, Xuan Chen, Shuang Hu, Xiaohong Bai, Miaomiao Luo
A novel oil-in-salt liquid-phase microextraction was developed and introduced for the extraction and concentration of the trace levels of active alkaloids in Coptis chinensis before analysis by high-performance liquid chromatography with UV detection. Also, the oil-in-salt extraction mechanism was analyzed, the enrichment factor and extraction recovery were redefined, and the proposed method was compared with other methods. In the approach, the mixed solvent of pentanol/octanol (6:4, v/v) and NaCl (20% w/v) are immobilized on the permutite surface in turn to form oil-in-salt double membranes, through which the target analytes can be molecularized though the salting-out effect and for extraction by an organic solvent...
January 20, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28106279/a-rapid-electrochemical-monitoring-platform-for-sensitive-determination-of-thiamethoxam-based-on-%C3%AE-cyclodextrin-graphene-composite
#20
XingChen Zhai, Hua Zhang, Min Zhang, Xin Yang, Cheng Gu, GuoPeng Zhou, Haitian Zhao, Zhenyu Wang, Aijun Dong, Jing Wang
A rapid monitoring platform for sensitive voltammetric detection of thiamethoxam (TMX) residues was reported in the present study. The β-cyclodextrin-reduced graphene oxide composite (β-CD-rGO) was used as a reinforcing material in electrochemical determination of TMX. Compared with bare glassy carbon electrode (GCE), the reduction peak currents of TMX at rGO/GCE and β-CD-rGO/GCE were increased by 70 and 124 folds, respectively. The experimental conditions influencing voltammetric determination of TMX, such as the amount of β-CD-rGO, solution pH, temperature and time on accumulation, were optimized...
January 20, 2017: Environmental Toxicology and Chemistry
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