Identification of Glycoproteins Containing Specific Glycans Using a Lectin-Chemical Method

Analytical ChemistryDOI: 10.1021/ac504304v

Pillar Cuvettes: Capillary-Filled, Microliter Quartz Cuvettes with Microscale Path Lengths for Optical Spectroscopy

Analytical ChemistryDOI: 10.1021/acs.analchem.5b00860

A Microfluidic Technique for Quantification of Steroids in Core Needle Biopsies

Analytical ChemistryDOI: 10.1021/ac5043297

Quantitative determination of dopamine in single rat pheochromocytoma cells by microchip electrophoresis with only one high-voltage power supply

We developed a method for the direct identification of dopamine in single cultured rat pheochromocytoma cells by capillary electrophoresis using an end-channel carbon fiber nanoelectrode amperometric detector. The operation mode was designed to achiev…

Monolithic capillary columns based on pentaerythritol acrylates for molecular-size-based separations of synthetic polymers

Monolithic capillary columns based on pentaerythritol triacrylate and pentaerythritol tetraacrylate were synthesized using different compositions of polymerization mixtures and different polymerization conditions. The impact of porogen type and poroge…

Direct determination of acrylamide in food by gas chromatography with nitrogen chemiluminescence detection

A method of gas chromatography with nitrogen chemiluminescence detection and using standard addition is described for the determination of acrylamide in heat-processed foods. Using a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) …

Reverse-phase HPLC method for the quantification of two antihyperglycemic glycolipids in Oplismenus burmannii

Glycolipids and sphingolipids are well known for their diverse biological activities like anticancer, anti-inflammatory, antistress, anti-HIV, hepatoprotective and antimicrobial. The present study deals with the activity-guided isolation and characterization of two antihyperglycemic glycolipids, (2S)-1,2-di-O-octadecanoyl-3-O-[α-d-galctopyranosyl-(1′′  6′)-O-β-d-galactopyranosyl] glycerol (1) and 1-O-β-d-glucopyranosyl-(2S,3S,4R,8E)-2-[(2R)-2-hydroxy-tetracosanoylamino]-2,3,4-octadecanetriol-8-ene (2) from Oplismenus burmannii and the development of a simple and validated reverse-phase HPLC analytical method for their quantification in the methanolic extracts of O. burmannii. The marker compounds 1 and 2 were isolated from the methanolic extract of O. burmannii and characterized on the basis of their spectroscopic data. Their antihyperglycemic potential was evaluated by determining their glucose uptake-stimulating potential in L6-GLUT4myc myotube cells. Finally, these analytes were separated on a Waters Spherisorb ODS 2 column with a binary gradient of methanol and water at a constant flow rate of 0.8 mL/min and detected using a photodiode array detector at 230 nm. The calibration curve was linear (r2 > 0.999) over 1.2 orders of magnitude with acceptable accuracy, reproducibility and recovery (98.16–100.50%). The limits of detection and quantification for 1 and 2 were 1.36, 4.11 and 1.11, 3.35 µg/mL respectively. The method is simple, accurate, precise and selective and may be routinely used for the quality control analysis of whole plant extract of O. burmannii for these two glycolipids. Copyright © 2015 John Wiley & Sons, Ltd.

Development and validation of a reversed-phase HPLC method for CYP1A2 phenotyping by use of a caffeine metabolite ratio in saliva

CYP1A2 is important for metabolizing various clinically used drugs. Phenotyping of CYP1A2 may prove helpful for drug individualization therapy. Several HPLC methods have been developed for quantification of caffeine metabolites in plasma and urine. Aim of the present study was to develop a valid and simple HPLC method for evaluating CYP1A2 activity during exposure in xenobiotics by the use of human saliva. Caffeine and paraxanthine were isolated from saliva by liquid-liquid extraction (chlorophorm/isopropanol 85/15v/v). Extracts were analyzed by reversed-phase HPLC on a C18 column with mobile phase 0.1% acetic acid/methanol/acetonitrile (80/20/2 v/v) and detected at 273nm. Caffeine and paraxanthine elution times were <13min with no interferences from impurities or caffeine metabolites. Detector response was linear (0.10–8.00µg/ml, R2>0.99), recovery was >93% and bias <4.47%. Intra- and inter-day precision was <5.14% (n=6). The limit of quantitation was 0.10µg/ml and the limit of detection was 0.018±0.002µg/mL for paraxanthine and 0.032±0.002µg/ml for caffeine. Paraxanthine/caffeine ratio of 34 healthy volunteers was significantly higher in smokers (p<0.001). Saliva paraxanthine/caffeine ratios and urine metabolite ratios were highly correlated (r=0.85, p<0.001). The method can be used for the monitoring of CYP1A2 activity in clinical practice and in studies relevant to exposure to environmental and pharmacological xenobiotics. Copyright © 2015 John Wiley & Sons, Ltd.

High-Throughput Characterization of Small and Large Molecules Using Only a Matrix and the Vacuum of a Mass Spectrometer

Analytical ChemistryDOI: 10.1021/ac504475x

Mapping Pixel Dissimilarity in Wide-Field Super-Resolution Fluorescence Microscopy

Analytical ChemistryDOI: 10.1021/ac504295p

Pulsed Microdischarge with Inductively Coupled Plasma Mass Spectrometry for Elemental Analysis on Solid Metal Samples

Analytical ChemistryDOI: 10.1021/acs.analchem.5b00397

Three-Dimensional Surface-Enhanced Raman Scattering Hotspots in Spherical Colloidal Superstructure for Identification and Detection of Drugs in Human Urine

Analytical ChemistryDOI: 10.1021/acs.analchem.5b00176

Anion-Exchange Chromatography of Phosphopeptides: Weak Anion Exchange versus Strong Anion Exchange and Anion-Exchange Chromatography versus Electrostatic Repulsion–Hydrophilic Interaction Chromatography

Analytical ChemistryDOI: 10.1021/ac504420c

Optimized hydrolysis and analysis of Radix Asparagi polysaccharide monosaccharide composition by capillary zone electrophoresis

Using orthogonal design, optimized conditions for hydrolysis of the polysaccharide from Radix Asparagi were determined, as well as its monosaccharide composition. Optimized hydrolysis conditions proved to be a temperature of 100ºC in 1.5 M sulfuric a…

Evaluation of pre-concentration methods in the analysis of synthetic musks in whole-water samples

According to the European Water Framework Directive, environmental assessment of organic compounds should be made in whole-water samples, but due to their hydrophobicity and strong attraction to organic content these compounds can be found bound to su…

Development and validation of a quantification method for ziyuglycoside I and II in rat plasma: Application to their pharmacokinetic studies

This study provided a novel and generally applicable method to determine ziyuglycoside I and ziyuglycoside II in rat plasma based on liquid chromatography with tandem mass spectrometry. A single step of liquid–liquid extraction with n-butanol was ut…

Determination of polycyclic aromatic hydrocarbons in fractions in asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization

An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined,…

The effects of cell detachment methods on the dielectric properties of adherent and suspension cells

Cell analyses such as flow cytometry, dielectrophoresis and some patch-clamp techniques require that cells be in monodisperse suspension in order for analysis to occur. Where cells have a normally adherent phenotype in vivo, this requires that cells b…

Electrodeposition of reduced graphene oxide on a Pt electrode and its use as amperometric sensor in microchip electrophoresis

This report describes the development and application of a novel graphene modified electrode to be used as amperometric sensor in microchip electrophoresis (ME) devices. The modified electrode was achieved based on electroreduction of graphene oxide o…

Improved protease digestion conditions for membrane protein detection

This work presents improved protease digestion conditions for membrane protein detection. The enzymatic digest of bacteriorhodopsin (BR), a model membrane protein with seven transmembrane domains (TMDs) was investigated. An initial in-gel digestion id…