title: Confirmation of clorsulon residues in cattle kidney by capillary gas chromatography-negative-ion chemical-ionization mass spectrometry.
abstract: A confirmatory assay for residues of the anthelmintic agent clorsulon [4-amino-6-(trichloroethenyl)-1,3-benzenedisulfonamide] in cattle kidney tissue has been developed. The assay involves isolation of a drug-containing fraction by solvent extraction, methylation of the analyte, and fused-silica capillary column gas chromatography-negative-ion chemical-ionization mass spectrometry of the pentamethyl derivative of clorsulon. The intensities of four negative ions [m/z 406 and 408 (trichloro species) and m/z 413 and 415 (dichloro species)] are monitored. Confirmation of the presence of drug in an analyte requires that all four ions appear at the appropriate retention time with their intensity ratios within 10-15% of those arising from analysis of the reference standard, methylated clorsulon; the lower limit of detection is 3 ppb. Quantification of the drug is based on the intensity of the m/z 406 ion. Identification and quantification of residues by the gas chromatographic-mass spectrometric assay gave results in good agreement with those obtained with an electron-capture gas chromatographic assay.
authors: Merck Sharp and Dohme Research Laboratories, Rahway, NJ 07065.
authors: T A
authors: TA
authors: Wehner
authors: J S
authors: JS
authors: Wood
authors: R
authors: R
authors: Walker
authors: G V
authors: GV
authors: Downing
authors: W J
authors: WJ
authors: Vandenheuvel
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000032:analysis*; D002417:Cattle; D008401:Gas Chromatography-Mass Spectrometry; D007202:Indicators and Reagents; D007668:Kidney / Q000032:analysis*; D013424:Sulfanilamides / Q000032:analysis*
chemical_list: D000871:Anthelmintics; D007202:Indicators and Reagents; D013424:Sulfanilamides; C015675:clorsulon