Qualitative and quantitative analysis of the major constituents in Jin-Mu-Gan-Mao tablet by high-performance liquid chromatography with diode-array detection and quadrupole time-of-flight tandem mass spectrometry

Jin-Mu-Gan-Mao tablet is a well-known traditional Chinese medicinal preparation, which has been used to treat the common cold in China. In this study, a systematic method was established for the qualitative and quantitative analysis of the major const…



Prestaining of glycoproteins in SDS-PAGE via with 4H-[1]-Benzopyrano[4,3-b]thiophene-2-carboxylic acid hydrazide with weak influence on protein mobility

A new fluorescent prestaining method for gel-separated glycoproteins in 1-D and 2-D SDS-PAGE was developed by using 4H-[1]-Benzopyrano[4,3-b]thiophene-2-carboxylic acid hydrazide (BH). The prestained gels were readily imaged after electrophoresis with…



“High frequency dielectrophoretic response of microalgae over time”

The high frequency dielectrophoresis (>20 MHz) response of microalgae cells with different lipid content was monitored over time. Chlamydomonas reinhardtii was cultured in regular medium and under nitrogen-depleted conditions in order to produce po…



Determination of acidity constants of sparingly soluble drugs in aqueous solution by the IS-CE method

A set of 33 drugs with different solubility, ranging to soluble to very insoluble ones, has been chosen in order to evaluate the performance of the internal standard capillary electrophoresis method (IS-CE) to determine acidity constants of compounds …



Validation and application of a modeling algorithm for the design of molecularly imprinted polymers

In the study, four different semi-empirical algorithms, Modified Neglect of Diatomic Overlap, a reparameterization of Austin Model 1, Complete Neglect of Differential Overlap and Typed Neglect of Differential Overlap, have been applied for energy opti…



Oxygen Control with Microfluidics

Lab Chip, 2014, Accepted ManuscriptDOI: 10.1039/C4LC00853G, Critical ReviewMartin Dean Brennan, Megan L. Rexius, Laura Jane Elgass, David T EddingtonCellular function and behavior are affected by the partial pressure of O2, or oxygen tension, in the mi…



A Sensitive capacitive immunosensor for direct detection of human heart fatty acid-binding protein (h-FABP)

Publication date: 15 January 2015
Source:Talanta, Volume 132
Author(s): Carmen-Marinela Mihailescu , Dana Stan , Rodica Iosub , Carmen Moldovan , Mihaela Savin
The fabrication of a capacitive interdigitated immunosensor (CID) based on a mixed self-assembled monolayer (mSAM) film for the direct detection of heart fatty-acid binding protein (h-FABP) without any labeling is described. The capacitance changes of mSAMs vs. homogenous ordered self-assembled monolayers (hSAMs) on gold work electrodes/covalently bonded antibodies/buffered medium are utilized for monitoring the specific antibody–antigen interaction. Capacitance measurements in the absence and presence of Faradaic currents were performed. The electrochemical properties of mixed monolayers were compared with those of a pure monolayer of 11-mercaptoundecanoic acid (MUA) self-assembled on gold surfaces. Taking into account the stability of the studied monolayers during the electrochemical experiments with the Faradaic process, the best SAM functionalization method was used for developing a sensitive capacitive immunosensor with a non-Faradaic process for direct immune detection of human h-FABP. Under the optimized conditions, the proposed mixed self-assembled monolayer (mSAM1) on gold electrode exhibited good insulating properties such as a capacitive behavior when detecting h-FABP from human serum in the range of 98pgml−1–100ngml−1, with a detection limit of 0.836ngml−1 comparative with a homogenous self-assembled monolayer (hSAM).

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Rapid determination of canagliflozin in rat plasma by UHPLC–MS/MS using negative ionization mode to avoid adduct-ions formation

Publication date: 15 January 2015
Source:Talanta, Volume 132
Author(s): Muzaffar Iqbal , Essam Ezzeldin , Khalid A. Al-Rashood , Yousif A. Asiri , Naser L. Rezk
Canagliflozin is the first sodium–glucose co-transporter-2 inhibitor, approved by the US Food and Drug Administration for the treatment of type 2 diabetes mellitus. In this study, a sensitive UHPLC–MS/MS assay for rapid determination of canagliflozin in rat plasma was developed and validated for the first time. Chromatographic separation of canagliflozin and zafirlukast (IS) was carried out on Acquity BEH C18 column (100×2.1mm, i.d. 1.7µm) using acetonitrile–water (80:20, v/v) as mobile phase at a flow rate of 0.3mLmin−1. Canagliflozin and IS were extracted from plasma by protein precipitation method using acetonitrile. The mass spectrometric detection was performed using electrospray ionization source in negative mode to avoid canagliflozin adduct ions formation. Multiple reaction monitoring were used for quantitation of precursor to product ion at m/z 443.16 >364.96 for canagliflozin and m/z 574.11>462.07 for IS, respectively. The assay was fully validated in terms of selectivity, linearity, accuracy, precision, recovery, matrix effects and stability. The validated method was successfully applied to the characterization of oral pharmacokinetic profiles of canagliflozin in rats. The mean maximum plasma concentration of canagliflozin of 1616.79ngmL−1 was achieved in 1.5h after oral administration of 20mgkg−1 in rats.

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Non-chromatographic speciation of chromium at sub-ppb levels using cloud point extraction in the presence of unmodified silver nanoparticles

Publication date: 15 January 2015
Source:Talanta, Volume 132
Author(s): Ignacio López-García , Yesica Vicente-Martínez , Manuel Hernández-Córdoba
The cloud point extraction (CPE) of silver nanoparticles (AgNPs) by Triton X-114 allows chromium (III) ions to be transferred to the surfactant-rich phase, where they can be measured by electrothermal atomic absorption spectrometry. Using 20mL sample and 50μL Triton X-114 (30% w/v), the enrichment factor was 1150, and calibration graphs were obtained in the 5–100ngL−1 chromium range in the presence of 5µgL−1 AgNPs. Speciation of trivalent and hexavalent chromium was achieved by carrying out two CPE experiments, one of them in the presence of ethylenediaminetetraacetate. While in the first experiment, in absence of the complexing agent, the concentration of total chromium was obtained, the analytical signal measured in the presence of this chemical allowed the chromium (VI) concentration to be measured, being that of chromium (III) calculated by difference. The reliability of the procedure was verified by using three standard reference materials before applying to water, beer and wine samples.

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Development of a MSFIA sample treatment system as front end of GC–MS for atenolol and propranolol determination in human plasma

Publication date: 15 January 2015
Source:Talanta, Volume 132
Author(s): María del Rosario Brunetto , Sabrina Clavijo , Yelitza Delgado , Wendy Orozco , Máximo Gallignani , Carlos Ayala , Víctor Cerdà
An on-line solid-phase extraction (SPE) method coupled to gas chromatography–mass spectrometry (GC–MS) has been developed for the determination of atenolol (ATN) and propranolol (PRO) in human plasma. The hyphenation of SPE with multisyringe flow injection analysis (MSFIA) allows the simultaneous GC–MS determination of ATN and PRO with high selectivity and sensitivity. On-line preconcentration and derivatisation of the analytes were carried out by means of using restricted access materials (RAM) and microwave (MW) assisted derivatisation reactions with N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA)+1% trimethylchlorosilane (TMCS). Multivariate optimization was applied to optimize experimental conditions. The whole procedure comprising sample pretreatment and analyte determination took about 15min. However, the overlap of the automatic sample treatment with the GC separation increased the frequency to 7samplesh−1. The validated method was successfully applied to direct ATN and PRO determination in human plasma.

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Single-Molecule Insights into Retention at a Reversed-Phase Chromatographic Interface

Analytical ChemistryDOI: 10.1021/ac5026418



Label-Free Biomarker Assay in a Microresistive Pulse Sensor via Immunoaggregation

Analytical ChemistryDOI: 10.1021/ac502270n



Polymer Topology Revealed by Ion Mobility Coupled with Mass Spectrometry

Analytical ChemistryDOI: 10.1021/ac502246g



Wavelet-Based spectral analysis

Publication date: Available online 16 September 2014 Source:TrAC Trends in Analytical Chemistry Author(s): Vu Dang Hoang Wavelets are a topic of pure mathematics. But over the past decade, they have shown great promise and are now bei…



Lanthanide-doped nanomaterials for luminescence detection and imaging

Publication date: Available online 16 September 2014 Source:TrAC Trends in Analytical Chemistry Author(s): Shiguo Wang , Leyu Wang Lanthanide-doped inorganic nanomaterials are a prominent class of nanocrystals with multicolor emissio…



Multivariate experimental design in environmental analysis

Publication date: Available online 16 September 2014 Source:TrAC Trends in Analytical Chemistry Author(s): M. Pilar Callao Environmental analysis comprises two major areas: the development of methods for determining contaminants and t…



Visual and fluorescent detection of acetamiprid based on the inner filter effect of gold nanoparticles on ratiometric fluorescence quantum dots

Publication date: Available online 16 September 2014
Source:Analytica Chimica Acta
Author(s): Xu Yan , Hongxia Li , Yang Li , Xingguang Su
In this work, we develop a simple and rapid sensing method for the visual and fluorescent detection of acetamiprid (AC) based on the inner-filter effect (IFE) of gold nanoparticles (AuNPs) on ratiometric fluorescent quantum dots (RF-QDs). The RF-QDs based dual-emission nanosensor was fabricated by assembling green emissive QDs (QDs539nm, λem=539nm) on the surface of red emissive QDs (QDs661nm, λem=661nm)-doped silica microspheres. The photoluminescence (PL) intensity of RF-QDs could be quenched by AuNPs based on IFE. Acetamiprid can adsorb on the surface of AuNPs due to its cyano group has good affinity with gold, which could induce the aggregation of AuNPs accompanying colour change from red to blue. Thus, the IFE of AuNPs on RF-QDs was weakened and the PL intensity of RF-QDs was recovered accordingly. Under the optimized conditions, the PL intensity of the RF-QDs/AuNPs system was proportional to the concentration of AC in the range of 0.025 to 5.0μgmL−1, with a detection limit of 16.8μgL−1. The established method had been used for AC detection in environmental and agricultural samples with satisfactory results.

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Ultrasensitive and simultaneous detection of heavy metal ions based on three-dimensional graphene-carbon nanotubes hybrid electrode materials

Publication date: Available online 16 September 2014
Source:Analytica Chimica Acta
Author(s): Hui Huang , Ting Chen , Xiuyu Liu , Houyi Ma
A green and facile method was developed to prepare a novel hybrid nanocomposite that consisted of one-dimensional multi-walled carbon nanotubes (MWCNTs) and two-dimensional graphene oxide (GO) sheets. The as-prepared three-dimensional GO–MWCNTs hybrid nanocomposites exhibit excellent water-solubility owing to the high hydrophilicity of GO components; meanwhile, a certain amount of MWCNTs loaded on the surface of GO sheets through π–π interaction seem to be “dissolved” in water. Moreover, the graphene(G)-MWCNTs nanocomposites with excellent conductivity were obtained conveniently by the direct electrochemical reduction of GO–MWCNTs nanocomposites. Seeing that there is a good synergistic effect between MWCNTs and graphene components in enhancing preconcentration efficiency of metal ions and accelerating electron transfer rate at G-MWCNTs/electrolyte interface, the G-MWCNTs nanocomposites possess fast, simultaneous and sensitive detection performance for trace amounts of heavy metal ions. The electrochemical results demonstrate that the G-MWCNTs nanocomposites can act as a kind of practical sensing material to simultaneously determine Pb2+ and Cd2+ ions in terms of anodic stripping voltammetry (ASV). The linear calibration plots for Pb2+ and Cd2+ ranged from 0.5μgL−1 to 30μgL−1. The detection limits were determined to be 0.2μgL−1 (S/N=3) for Pb2+ and 0.1μgL−1 (S/N=3) for Cd2+ in the case of a deposition time of 180s. It is worth mentioning that the G-MWCNTs modified electrodes were successfully applied to the simultaneous detection of Cd2+ and Pb2+ ions in real electroplating effluent samples containing lots of surface active impurities, showing a good application prospect in the determination of trace amounts of heavy metals.

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An integrated microfluidic device utilizing dielectrophoresis and multiplex array PCR for point-of-care detection of pathogens

Lab Chip, 2014, 14,3917-3924DOI: 10.1039/C4LC00669K, PaperDongyang Cai, Meng Xiao, Peng Xu, Ying-Chun Xu, Wenbin DuAn integrated device utilizing dielectrophoresis and multiplex array PCR for the point-of-care identification of pathogens in complex phy…



Modeling and optimization of acoustofluidic micro-devices

Lab Chip, 2014, 14,3937-3948DOI: 10.1039/C4LC00714J, PaperPhilipp Hahn, Olivier Schwab, Jurg DualDesign by optimization reduces the development time of new acoustofluidic micro-devices and maximizes their acoustophoretic performance.The content of this…