Improved cleanup for liquid chromatographic analysis and fluorescence detection of aflatoxins M1 and M2 in fluid milk products.
A rapid method is described for extraction and cleanup of raw and processed milk for determination of aflatoxins M1 and M2 by using a C18 Sep-Pak/silica gel cleanup column combination. Aflatoxins are separated by normal phase liquid chromatography and their concentrations are determined by fluorescence detection in a silica gel-packed flow cell. Recoveries ranged from 99 to 103% with coefficients of variation less than 2% for M1 levels of 0.117-1.17 ng/mL added to raw milk. Similar recoveries were obtained for M2. The coefficient of variation for analysis of 5 subsamples of naturally contaminated milk was less than 1%. Agreement with the official method is satisfactory. Each sample requires less than 25 mL solvent and 10 min actual handling time. Sample chromatograms show no interferences in the M1-M2 elution region and no late-eluting peaks, which permits spacing injections at 13-20 min intervals. Aflatoxin levels as low as 0.03 ppb may be determined by this procedure. Extracts have also been analyzed by thin layer chromatography.
D016607:Aflatoxin M1; D000348:Aflatoxins / Q000032:analysis; D000818:Animals; D002417:Cattle; D002849:Chromatography, Gas / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods; D003611:Dairy Products / Q000032:analysis*; D005516:Food Microbiology; D008892:Milk / Q000032:analysis*; D013050:Spectrometry, Fluorescence / Q000379:methods
D000348:Aflatoxins; D016607:Aflatoxin M1; C030379:aflatoxin M2