Development and application of an analytical method for curdione quantification in pregnant sprague–dawley rats by LC-MS/MS

The vaginal administration route suffers from relatively low absorption efficiency, which may hinder the identification of the toxicokinetics of curdione in pregnant women. A sensitive analytical method for determining the plasma concentration of curdione was developed and applied in the determination of curdione in pregnant Sprague–Dawley rats as a simulated model. Glimepiride was used as an internal standard and chromatographic separation was achieved on a Capcell Pak C18 MGIII column. A gradient elution profile with 0.5% formic acid (A)–0.5% formic acid–acetonitrile (B) was selected as mobile phase. The selected reaction monitoring mode was used for quantification based on the target fragment ions m/z 237.2 to m/z 135.1 for curdione and m/z 491.3 to m/z 352.1 for the glimepiride. The standard curve was linear over the range of 0.5–500 ng/mL for curdione in rat plasma and yielded a consistent peak pattern, even at the lower limit of quantitation of 0.5 ng/mL. The retention times of curdione and IS were 6.55 and 6.59 min, respectively. The mean recovery of curdione in rat plasma was 95.5–101.1%. The intra-day and inter-day precisions were between 2.35 and 9.08%. This LC-MS/MS method provides a simple and sensitive means for determining the plasma concentration. Copyright © 2015 John Wiley & Sons, Ltd.



Simple extraction method using syringe filter for detection of ethephon in tomatoes by negative-ion mode liquid chromatography with tandem mass spectrometry

In this study, a simple, rapid, and sensitive method was developed for the extraction of ethephon from homogenized tomatoes that does not require a cleanup procedure. In a syringe filter, three distinct layers – aqueous, acetonitrile, and n-hexane – are clearly separated after storage at −80 °C for 5–10 min. A Dionex IonPac column was used to separate the analyte before detection using negative-ion mode liquid chromatography with tandem mass spectrometry (LC/MS/MS). The matrix effect of the tested analyte was negligibly small and the matched calibration showed a good linearity over a concentration range of 0.01–1.0 mg/kg with a correlation coefficient (R2) of 0.9998. The recovery at three fortification levels (0.1, 0.5 and 1.0 mg/kg) was between 82.9 and 108.6% with relative standard deviations (RSDs) <5.0%. The limit of quantification (0.03 mg/kg) was lower than the maximum residue limit (3 mg/kg) set by the Ministry of Food and Drug Safety, Republic of Korea. From a field trial, the method developed herein was applied to calculate the decline pattern and predict the pre-harvest residue limits of ethephon in tomatoes. In conclusion, the proposed sample preparation is feasible for the detection of hydrophilic analytes in tomatoes. Copyright © 2015 John Wiley & Sons, Ltd.



Development of a LC-MS/MS method for simultaneous determination of metoprolol and its metabolites, α-hydroxymetoprolol and O-desmethylmetoprolol, in rat plasma: application to the herb–drug interaction study of metoprolol and breviscapine

A simple, specific and sensitive LC-MS/MS method was developed and validated for the simultaneous determination of metoprolol (MET), α-hydroxymetoprolol (HMT) and O-desmethylmetoprolol (DMT) in rat plasma. The plasma samples were prepared by protein precipitation, then the separation of the analytes was performed on an Agilent HC-C18 column (4.6 × 250 mm, 5 µm) at a flow rate of 1.0 mL/min, and post-column splitting (1:4) was used to give optimal interface flow rates (0.2 mL/min) for MS detection; the total run time was 8.5 min. Mass spectrometric detection was achieved using a triple-quadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode. The method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, matrix effect and recovery over a concentration range of 3.42–7000 ng/mL for MET, 2.05-4200 ng/mL for HMT and 1.95-4000 ng/mL for DMT. The analytical method was successfully applied to herb–drug interaction study of MET and breviscapine after administration of breviscapine (12.5 mg/kg) and MET (40 mg/kg). The results suggested that breviscapine have negligible effect on pharmacokinetics of MET in rats; the information may be beneficial for the application of breviscapine in combination with MET in clinical therapy. Copyright © 2015 John Wiley & Sons, Ltd.



Simultaneous Analysis of Hydrodynamic and Optical Properties Using Analytical Ultracentrifugation Equipped with Multiwavelength Detection

Analytical ChemistryDOI: 10.1021/ac504649c



Detection of S-Nitroso Compounds by Use of Midinfrared Cavity Ring-Down Spectroscopy

Analytical ChemistryDOI: 10.1021/ac5045143



GTP-Specific Fab Fragment-Based GTPase Activity Assay

Analytical ChemistryDOI: 10.1021/acs.analchem.5b00117



Ratiometric Iridium(III) Complex-Based Phosphorescent Chemodosimeter for Hg2+ Applicable in Time-Resolved Luminescence Assay and Live Cell Imaging

Analytical ChemistryDOI: 10.1021/ac503878s



Pt@UiO-66 Heterostructures for Highly Selective Detection of Hydrogen Peroxide with an Extended Linear Range

Analytical ChemistryDOI: 10.1021/ac5047278



Organic Building Block Based Microporous Network SNW-1 Coating Fabricated by Multilayer Interbridging Strategy for Efficient Enrichment of Trace Volatiles

Analytical ChemistryDOI: 10.1021/ac504594d



Structural Resolution of 4-Substituted Proline Diastereomers with Ion Mobility Spectrometry via Alkali Metal Ion Cationization

Analytical ChemistryDOI: 10.1021/ac5043285



Contents: J. Sep. Science 5’15



Contents: J. Sep. Science 5’15



Cover Picture: J. Sep. Science 5’15



Bottom-Up and Middle-Down Proteomics Have Comparable Accuracies in Defining Histone Post-Translational Modification Relative Abundance and Stoichiometry

Analytical ChemistryDOI: 10.1021/acs.analchem.5b00072



Membrane Electrospray Ionization for Direct Ultrasensitive Biomarker Quantitation in Biofluids Using Mass Spectrometry

Analytical ChemistryDOI: 10.1021/acs.analchem.5b00467



Facile One-Step Photochemical Fabrication and Characterization of an Ultrathin Gold-Decorated Single Glass Nanopipette

Analytical ChemistryDOI: 10.1021/ac5034165



Assessing the detectability of antioxidants in two-dimensional high-performance liquid chromatography

This paper explores the analytical figures of merit of two-dimensional high-performance liquid chromatography for the separation of antioxidant standards. The cumulative two-dimensional high-performance liquid chromatography peak area was calculated f…



A microextraction procedure based a task-specific ionic liquid for the separation and determination of lead ions in red lipstick and pine leaves

First, the extraction and pre-concentration of ultra-trace amounts of lead(II) ions was performed using microliter volumes of a task-specific ionic liquid. The remarkable properties of ILs were added to the advantages of microextraction procedure. The…



Feedback-amplified electrochemical dual-plate boron-doped diamond micro-trench detector for flow injection analysis

An electrochemical flow cell with a boron-doped diamond (BDD) dual-plate micro-trench electrode has been developed and demonstrated for hydroquinone flow injection electroanalysis in phosphate buffer pH 7. Using the electrochemical generator-collector…



Microchip electrophoresis-single wall carbon nanotube press-transferred electrodes for fast and reliable electrochemical sensing of melatonin and its precursors

In the current work, single wall carbon nanotube press-transferred electrodes (SW-PTEs) were used for detection of melatonin (MT) and its precursors tryptophan (Trp) and serotonin (5-HT) on microchip electrophoresis (ME). SW-PTEs were simply fabricate…