Rong Liu

South China Agricultural University, Guangzhou, Guangdong Sheng, China

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Publications (3)2.03 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: A cheap, reliable and practical high-performance liquid chromatography-tandem mass spectrometric method was developed for the simultaneous determination of seven anabolic steroids in eggs, including trenbolone, boldenone, nandrolone, stanozolol, methandienone, testosterone and methyl testosterone. The analytes were extracted from the egg samples using methanol. The extracts were subjected to the removal of fat by freezing-lipid filtration and then further purified by liquid-liquid extraction using tert-butyl methyl ether. The analytes were separated on a Luna C18 column by a gradient elution program with 0.1% formic acid and acetonitrile. This method was validated over 1.00-100 ng/g for all steroids of interest. The correlation coefficients (r) for each calibration curve are higher than 0.99 within the experimental concentration range. The decision limits of the steroids in eggs ranged from 0.20 to 0.44 ng/g, and the detection capabilities were below 1.03 ng/g. The average recoveries were between 66.3 and 82.8% in eggs at three spiked levels of 1.00, 1.50 and 2.00 ng/g for each analyte. The between-day and within-day relative standard deviations were in the range of 2.4-11%. High matrix suppression effects were observed for all compounds of interest.
    Journal of chromatographic science 08/2012; · 0.79 Impact Factor
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    ABSTRACT: A sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed for the simultaneous determination of the tranquilizers (chlorpromazine, promethazine, diazepam, azaperone and its metabolite, azaperol) and a β-blocker (carazolol) in edible swine tissues. Sample was subjected to extract with acetonitrile, clean up by Oasis HLB solid phase extraction cartridge, and then analyzed by LC-MS-MS in multiple reaction monitoring positive ionization mode. The matrix-matched calibration curves were linear within the dynamic range of each analyte with a correlation coefficient higher than 0.99. The average recoveries of tranquilizers and carazolol spiked at three levels ranged from 74.2% to 91.8% with the relative standard deviation below 15%. The limits of detection were between 0.06 and 0.1 µg kg and the limits of quantification were between 0.2 and 0.4 µg kg for all analytes in swine muscle, liver and kidney.
    Analytical Letters - ANAL LETT. 01/2012;
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    ABSTRACT: Clopidol was extracted from chicken with acetonitrile, and the extract was evaporated to about 5 mL. The concentrated solution was centrifuged and applied to a glass column filled with basic alumina. The column was eluted with methanol and the methanol was evaporated to dryness. The residue was derivatized with Sylon BFT and analyzed by gas chromatography/mass spectrometry (GC/MS). Mass characteristics of trimethylsilyl derivative of clopidol were interpreted manually. The selected-ion monitoring mode was performed at m/z 191, 248, 263, and 265. A sensitive, reproducible GC/MS method was developed for monitoring residues of clopidol in chickens. All recoveries of the drug from chicken muscle fortified at 1, 10, and 100 ng/g were > 65%, and relative standard deviations were < 15%. The detection limit was about 0.5 ng/g, and the quantitation limit was the lower limit of the standard curve, which was about 1 ng/g.
    Journal of AOAC International 01/2005; 88(4):1104-7. · 1.23 Impact Factor