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https://www.readbyqxmd.com/read/28532053/functionalized-fe3o4-graphene-oxide-nanocomposites-with-hairpin-aptamers-for-the-separation-and-preconcentration-of-trace-pb-2-from-biological-samples-prior-to-determination-by-icp-ms
#1
Mojtaba Shamsipur, Leila Farzin, Mahmoud Amouzadeh Tabrizi, Shahab Sheibani
Lead (Pb) as a topically poisonous metal represents a serious threat to the ecological environment and especially to human beings. Therefore, it is urgent to develop a rapid and reliable monitoring technique for this heavy metal in the environmental samples. In the present study, we have designed a selective and sensitive method for the determination of ultratrace contents of Pb(2+) in biological samples, based on the guanine (G)-quadruplex formed by the aptamer with hairpin structure and Pb(2+). For this purpose, Pb(2+) specific aptamer serving as affinity probe to capture and separate trace amounts of the analyte, was covalently linked to Fe3O4/graphene oxide (GO) surface by using a suitable cross-linking agent...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531844/development-of-an-uplc-ms-ms-method-for-simultaneous-quantitation-of-11-d-amino-acids-in-different-regions-of-rat-brain-application-to-a-study-on-the-associations-of-d-amino-acid-concentration-changes-and-alzheimer-s-disease
#2
Zhe Li, Yuping Xing, Xingjie Guo, Yan Cui
There are significant differences in d-amino acid concentrations between healthy people and Alzheimer's disease patients. In order to investigate the potential correlation between d-amino acids and Alzheimer's disease, a simple and sensitive ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed. The method was applied to simultaneous determination of 11 d-amino acids in different regions of rat brain. Rat brain homogenates were firstly pretreated with protein precipitation procedure and then derivatized with (S)-N-(4-nitrophenoxycarbonyl) phenylalanine methoxyethyl ester [(S)-NIFE]...
May 11, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28530554/simultaneous-determination-of-fumonisins-b1-and-b2-in-different-types-of-maize-by-matrix-solid-phase-dispersion-and-hplc-ms-ms
#3
Gabriel Barros de Oliveira, Carolyne Menezes de Castro Gomes Vieira, Ricardo Mathias Orlando, Adriana Ferreira Faria
This work involved the optimization and validation of a method, according to Directive 2002/657/EC and the Analytical Quality Assurance Manual of Ministério da Agricultura, Pecuária e Abastecimento, Brazil, for simultaneous extraction and determination of fumonisins B1 and B2 in maize. The extraction procedure was based on a matrix solid phase dispersion approach, the optimization of which employed a sequence of different factorial designs. A liquid chromatography-tandem mass spectrometry method was developed for determining these analytes using the selected reaction monitoring mode...
October 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28528283/poly-vinyl-alcohol-hydroxyapatite-monolithic-in-needle-extraction-mine-device-preparation-and-examination-of-drug-affinity
#4
Monika Pietrzyńska, Michał Czerwiński, Adam Voelkel
Polymer-ceramic materials based on poly(vinyl alcohol) (PVA) and hydroxyapatite were applied as sorption material in Monolithic In-Needle Extraction (MINE) device. The presented device provides new possibilities for the examination of bisphosphonates affinity for bone and will be a helpful tool in evaluation of potential antiresorptive drugs suitability. A ceramic part of monoliths was prepared by incorporation of hydroxyapatite (HA) into the reaction mixture or by using a soaking method (mineralization of HA on the PVA)...
May 17, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28527516/a-feasible-economical-and-accurate-analytical-method-for-simultaneous-determination-of-six-alkaloid-markers-in-aconiti-lateralis-radix-praeparata-from-different-manufacturing-sources-and-processing-ways
#5
Yi-Bei Zhang, Juan DA, Jing-Xian Zhang, Shang-Rong Li, Xin Chen, Hua-Li Long, Qiu-Rong Wang, Lu-Ying Cai, Shuai Yao, Jin-Jun Hou, Wan-Ying Wu, De-An Guo
Aconiti Lateralis Radix Praeparata (Fuzi) is a commonly used traditional Chinese medicine in clinic for its potency in restoring yang and rescuing from collapse. Aconiti alkaloids, mainly including monoester-diterpenoidaconitines (MDAs) and diester-diterpenoidaconitines (DDAs), are considered to act as both bioactive and toxic constituents. In the present study, a feasible, economical, and accurate HPLC method for simultaneous determination of six alkaloid markers using the Single Standard for Determination of Multi-Components (SSDMC) method was developed and fully validated...
April 2017: Chinese Journal of Natural Medicines
https://www.readbyqxmd.com/read/28525867/evaluation-of-alternative-environmentally-friendly-matrix-solid-phase-dispersion-solid-supports-for-the-simultaneous-extraction-of-15-pesticides-of-different-chemical-classes-from-drinking-water-treatment-sludge
#6
Karina Lotz Soares, Maristela Barnes Rodrigues Cerqueira, Sergiane Souza Caldas, Ednei Gilberto Primel
This study describes the development, optimization and validation of a method for the extraction of 15 pesticides of different chemical classes in drinking water treatment sludge (DWTS) by vortex-assisted Matrix Solid Phase Dispersion (MSPD) with determination by gas chromatography coupled to mass spectrometry. It focused on the application of alternative and different solid supports to the extraction step of the MSPD. The main parameters that influenced the extraction were studied in order to obtain better recovery responses...
May 12, 2017: Chemosphere
https://www.readbyqxmd.com/read/28525850/highly-sensitive-aptasensor-based-on-fluorescence-resonance-energy-transfer-between-l-cysteine-capped-zns-quantum-dots-and-graphene-oxide-sheets-for-the-determination-of-edifenphos-fungicide
#7
Majid Arvand, Aazam A Mirroshandel
With the advantages of excellent optical properties and biocompatibility, single-strand DNA-functionalized quantum dots have been widely applied in biosensing and bioimaging. A new aptasensor with easy operation, high sensitivity, and high selectivity was developed by immobilizing the aptamer on water soluble l-cysteine capped ZnS quantum dots (QDs). Graphene oxide (GO) sheets are mixed with the aptamer-QDs. Consequently, the aptamer-conjugated QDs bind to the GO sheets to form a GO/aptamer-QDs ensemble. This aptasensor enables the energy transfer based on a fluorescence resonance energy transfer (FRET) from the QDs to the GO sheets, quenching the fluorescence of QDs...
May 12, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28525791/determination-of-thiopurine-s-methyltransferase-activity-by-hydrophilic-interaction-liquid-chromatography-hyphenated-with-mass-spectrometry
#8
Daniel Pecher, Svetlana Dokupilová, Zuzana Zelinková, Maikel Peppelenbosch, Veronika Mikušová, Peter Mikuš
Thiopurine S-methyltransferase (TPMT) plays an important role in the metabolism of thiopurines used in the therapy of inflammatory bowel diseases (IBD). In this work a new progressive method for the determination of TPMT activity in red blood cells lysates was developed. Analysis was carried out by means of hydrophilic interaction liquid chromatography (HILIC) hyphenated with mass spectrometry (MS). In comparison with reversed-phase high-performance liquid chromatography (RP-HPLC), that has been typically applied in determination of TPMT activity, the HILIC significantly improved the analytical signal provided by MS, shortened analysis time, and improved chromatographic resolution...
May 10, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28521528/prevention-and-control-of-emergent-infectious-disease-with-high-specific-antigen-sensor
#9
Hongzhe Zhang, Shanshan Zhang, Nan Liu
This study aims to evaluate the application of a new type of high specificity antigen sensor in detecting the viruses in sudden infectious diseases. Influenza A (H1N1) virus immunosensor was used for the respective determination of the six kinds of antigens of H1N1, H3N2 viral protein, HA protein of H7N9, influenza B virus, adenovirus, and EV71 virus of same dilution degree on the Screen Printed Carbon Electrode (SPCE), so as to test the specificity of the detection method. In addition, various batches of chick embryo allantoic saliva dilution simulation samples were also detected on their recovery (accuracy), repeatability (precision), and stability...
May 18, 2017: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/28520400/femtomole-scale-high-throughput-screening-of-protein-ligands-with-droplet-based-thermal-shift-assay
#10
Wen-Wen Liu, Ying Zhu, Qun Fang
There is a great demand to measure protein-ligand interactions in rapid and low cost way. Here we developed a microfluidic droplet-based thermal shift assay (dTSA) system for high throughput screening of small-molecule protein ligands. The system is composed of a nanoliter droplet array chip, a microfluidic droplet robot, and a real-time fluorescence detection system. Total 324 assays could be performed in parallel in a single chip with an 18 × 18 droplet array. The consumption of dTSA for each protein or ligand sample was only 5 nL (femtomole scale), which is significantly reduced by over 3 orders of magnitude compared with those in 96 or 384-well plate-based systems...
May 18, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28516982/colorimetric-and-electrochemical-quantification-of-global-dna-methylation-using-a-methyl-cytosine-specific-antibody
#11
Md Hakimul Haque, Ripon Bhattacharjee, Md Nazmul Islam, Vinod Gopalan, Nam-Trung Nguyen, Alfred K Lam, Muhammad J A Shiddiky
We report a simple colorimetric (naked-eye) and electrochemical method for the rapid, sensitive and specific quantification of global methylation levels using only 25 ng of input DNA. Our approach utilises a three-step strategy; (i) initial adsorption of the extracted, purified and denatured bisulfite-treated DNA on a screen-printed gold electrode (SPE-Au), (ii) immuno-recognition of methylated DNA using a horseradish peroxidase (HRP)-conjugated methylcytosine (HRP-5mC) antibody and (iii) subsequent colorimetric detection by the enzymatic oxidation of 3,3',5,5'-tetramethylbenzidin (TMB)/H2O2 which generated a blue-coloured product in the presence of methylated DNA and HRP-5mC immunocomplex...
May 18, 2017: Analyst
https://www.readbyqxmd.com/read/28516279/a-new-carbon-based-magnetic-material-for-the-dispersive-solid-phase-extraction-of-uv-filters-from-water-samples-before-liquid-chromatography-tandem-mass-spectrometry-analysis
#12
Susy Piovesana, Anna Laura Capriotti, Chiara Cavaliere, Giorgia La Barbera, Roberto Samperi, Riccardo Zenezini Chiozzi, Aldo Laganà
Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe3O4-graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m(2) g(-1) surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe3O4 microparticles...
May 18, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28509533/a-low-cost-label-free-biosensing-bimetallic-cellulose-strip-with-silar-synthesized-silver-core-gold-shell-nanoparticle-structures
#13
Wansun Kim, Jae-Chul Lee, Gi-Ja Lee, Hun-Kuk Park, Anbok Lee, Samjin Choi
We introduce a label-free biosensing cellulose strip sensor with surface-enhanced Raman spectroscopy (SERS)-encoded bimetallic core@shell nanoparticles. Bimetallic nanoparticles consisting of a synthesis of core Ag nanoparticles (AgNP) and a synthesis of shell gold nanoparticles (AuNPs) were fabricated on a cellulose substrate by two-stage successive ionic layer absorption and reaction (SILAR) techniques. The bimetallic nanoparticle-enhanced localized surface plasmon resonance (LSPR) effects were theoretically verified by computational calculations with finite element models of optimized bimetallic nanoparticles interacting with an incident laser source...
May 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28506057/liquid-spray-dielectric-barrier-discharge-induced-plasma-chemical-vapor-generation-for-the-determination-of-lead-by-icp-ms
#14
Xing Liu, Zhenli Zhu, Huilai Li, Dong He, Yatai Li, Hongtao Zheng, Yiqun Gan, Yanxiang Li, Nicholas Stanley Belshaw, Shenghong Hu
In the present study, a novel and sensitive liquid spray dielectric barrier discharge induced plasma-chemical vapor generation technique (LSDBD-CVG) is developed for the determination of lead concentration by inductively coupled plasma mass spectrometry (ICP-MS). The dissolved Pb(2+) is readily converted to volatile species by LSDBD plasma induced chemical processes in the presence of 5% (v/v) formic acid in a supporting electrolyte (HCl, 0.01 mol L(-1)). In this LSDBD approach, the sample solution is converted to aerosol and simultaneously mixed with the DBD plasma generated at the nozzle of a pneumatic nebulizer, which greatly facilitates Pb vapor generation because of the enhanced interaction of sprayed analytes and the plasma...
May 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28505493/development-of-an-analysis-method-for-determination-of-sulfonamides-and-their-five-acetylated-metabolites-in-baby-foods-by-ultra-high-performance-liquid-chromatography-coupled-to-high-resolution-mass-spectrometry-orbitrap-ms
#15
Ülgen I Konak, Muharrem Certel, Bülent Şık, Timur Tongur
A high sensitive and reliable multiresidue method was developed and validated for determination of twelve sulfonamides and five acetylated metabolites in baby foods by using UHPLC-Orbitrap-MS. The sample preparation included two extraction methods as QuEChERS and ASE. The original QuEChERS method was performed, whereas ASE method was optimized to achieve the best recovery for all analytes. UHPLC-Orbitrap-MS parameters were optimized to obtain good retention and separation in LC and high sensitivity and selectivity in MS...
July 1, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28505432/development-of-a-new-extraction-device-based-on-parallel-electromembrane-extraction
#16
Nicolas Drouin, Jean-François Mandscheff, Serge Rudaz, Julie Schappler
A new device for parallel-electromembrane extraction (Pa-EME) was developed to enable simultaneous and high-throughput extraction of ionic and ionizable compounds from biofluids. The new system is composed of a reusable conductive well-plate used as an acceptor compartment and a commercial filtration well-plate used as a donor com-partment. A design of experiments was implemented to optimize the main experimental parameters (agitation, voltage, and time) with standard solutions in formic acid 50 mM. The stirring rate was found the primary influent parameter...
May 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28505421/development-of-high-performance-chemical-isotope-labeling-lc-ms-for-profiling-the-carbonyl-submetabolome
#17
Shuang Zhao, Margot Dawe, Kevin Guo, Liang Li
Metabolites containing a carbonyl group represent several important classes of molecules including various forms of ketones and aldehydes such as steroids and sugars. We report a high-performance chemical isotope labeling (CIL) LC-MS method for profiling the carbonyl submetabolome with high coverage and high accuracy and precision of relative quantification. This method is based on the use of dansylhydrazine (DnsHz) labeling of carbonyl metabolites to change their chemical and physical properties to such an extent that the labeled metabolites can be efficiently separated by reversed phase LC and ionized by electrospray ionization MS...
May 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28503547/theoretically-guided-analytical-method-development-and-validation-for-the-estimation-of-rifampicin-in-a-mixture-of-isoniazid-and-pyrazinamide-by-uv-spectrophotometer
#18
Mohammad F Khan, Shamima A Rita, Md Shahidulla Kayser, Md Shariful Islam, Sharmeen Asad, Ridwan Bin Rashid, Md Abdul Bari, Muhammed M Rahman, D A Anwar Al Aman, Nurul I Setu, Rebecca Banoo, Mohammad A Rashid
A simple, rapid, economic, accurate, and precise method for the estimation of rifampicin in a mixture of isoniazid and pyrazinamide by UV spectrophotometeric technique (guided by the theoretical investigation of physicochemical properties) was developed and validated. Theoretical investigations revealed that isoniazid and pyrazinamide both were freely soluble in water and slightly soluble in ethyl acetate whereas rifampicin was practically insoluble in water but freely soluble in ethyl acetate. This indicates that ethyl acetate is an effective solvent for the extraction of rifampicin from a water mixture of isoniazid and pyrazinamide...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28502424/redox-speciation-of-iron-manganese-and-copper-in-cerebrospinal-fluid-by-strong-cation-exchange-chromatography-sector-field-inductively-coupled-plasma-mass-spectrometry
#19
Nikolay Solovyev, Marco Vinceti, Peter Grill, Jessica Mandrioli, Bernhard Michalke
A new method of simultaneous redox speciation of iron (II/III), manganese (II/III), and copper (I/II) in cerebrospinal fluid (CSF) has been designed. For the separation of redox species strong cation exchange chromatography (SCX) with isocratic elution was employed. Species were detected using inductively coupled plasma sector field mass spectrometry (ICP-sf-MS), operating at medium resolution. The following parameters were optimized: analytical column, eluent composition and pH, CSF injection volume and dilution factor...
June 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28501214/capillary-electrophoresis-tandem-mass-spectrometry-determination-of-glutamic-acid-and-homocysteine-s-metabolites-potential-biomarkers-of-amyotrophic-lateral-sclerosis
#20
Zuzana Cieslarova, Fernando Silva Lopes, Claudimir Lucio do Lago, Marcondes Cavalcante França, Ana Valéria Colnaghi Simionato
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects both lower and upper motor neurons, leading to muscle atrophy, paralysis, and death caused by respiratory failure or infectious complications. Altered levels of homocysteine, cysteine, methionine, and glutamic acid have been observed in plasma of ALS patients. In this context, a method for determination of these potential biomarkers in plasma by capillary electrophoresis tandem mass spectrometry (CE-MS/MS) is proposed herein. Sample preparation was carefully investigated, since sulfur-containing amino acids may interact with plasma proteins...
August 1, 2017: Talanta
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