我在故我思
第4楼2009/01/28
Determination of residues of propamocarb in wine by liquid chromatography-electrospray mass spectrometry with direct injection
J.C.Taylor, et al.
Food Additives & Contaminants: Part A, Volume 21, Issue 6 June 2004 , pages 572 - 577
Abstract:
A simple, sensitive and reliable liquid chromatography-mass spectrometry method with direct injection of diluted samples is reported for the determination of propamocarb residues in wine. Red and white wines were diluted 40- and 20-fold, respectively, using water. Liquid chromatography was performed with a mobile-phase gradient and detection was by electrospray mass spectrometry in a positive ionization mode. Propamocarb was detected as the protonated molecular species at m/z 189. Using matrix-matched calibrant solutions, a calibrated range equivalent to 0.05-2.0 mg kg-1 in red and white wines and limits of detection of 0.025 mg kg-1 for white wine and of 0.05 mg kg-1 for red wine (0.00125 μg ml-1 of sample solution injected) were readily achievable. Recovery of propamocarb hydrochloride from wine spiked before dilution was in the range 91-115%. The chromatograms were free of isobaric interferences. In a small wine survey (72 samples), no residues of propamocarb were detected above 0.1 mg kg-1.
http://www.informaworld.com/smpp/content~content=a713599761~db=all
我在故我思
第5楼2009/01/28
Determination of propamocarb in vegetables using polymer-based high-performance liquid chromatography coupled with electrospray mass spectrometry
Maurice Hiemstra, André de Kok
Journal of Chromatography A Volume 972, Issue 2, 4 October 2002, Pages 231-239
Abstract
A method for the determination of propamocarb in vegetables with liquid chromatography–electrospray ionisation mass spectrometry ($$lc–ESI-MS) was developed. The performance of a polymer-based analytical $$lc column for the separation was investigated. Residues of propamocarb were extracted from the matrix with methanol. Subsequently, the extract was directly injected into the $$lc–MS system, without any additional concentration or cleanup procedures. Separation of propamocarb from the matrix components was achieved on a polymethacrylate-based analytical column. Propamocarb was concurrently detected with electrospray ionisation mass spectrometry in the selected ion monitoring mode and two-stage full scan MS application. Quantitation was done with matrix-matched calibration standards of propamocarb. Unambiguous confirmation was achieved by comparison of the full scan product ion mass spectrum of the chromatographic peak in the sample with the spectrum of a standard solution of propamocarb at the same retention time. The analytical performance of the method was validated for five relevant matrices, spiking propamocarb at fortification levels from 0.05 to 15.0 mg kg−1. This covers the range of maximum residue limits in agricultural commodities, stated in the Dutch national legislation. The mean recovery of propamocarb was better than 90% with a precision of less than 10% in both scanning applications. As could be concluded from the calibration curve and matrix background levels, observed in blank control samples, the estimated limit of detection was 25 μg kg−1 for the two-stage full scan MS application. The method has been applied in a survey of 285 samples of lettuce, radish, leek, and cabbage for the presence of residues of propamocarb. In 50% of the samples analysed, a residue of propamocarb was detected.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TG8-46P1PRX-B&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=fc5a5a9af3df12563e6c9d4637295e7f