Conditions were optimized for the simultaneous, alkaline, aqueous methanol extraction of aflatoxins (AFL), i.e., B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2), and ochratoxin A (OTA) with subsequent
purification, isolation, and determination of the toxins in ginseng and ginger. Powdered roots were extracted with methanol0.5% NaHCO3 solution (7 + 3). After shaking and centrifugation, the supernatant was diluted with 100 mM phosphate buffer containing 1% Tween 20 and filtered
through glass microfiber filter paper. The filtrate was then passed through an immunoaffinity column, and the toxins were eluted with methanol. The AFL were separated and determined by reversed-phase liquid chromatography (RPLC) with fluorescence detection after postcolumn UV photochemical
derivatization. OTA was separated and determined by RPLC with fluorescence detection. Recoveries of AFL added at 216 ng/g and OTA added at 18 ng/g to ginseng were 7280 and 8695%, respectively. Recoveries of AFL and OTA added to ginger were similar to those for ginseng. A total of 39 commercially
available ginger products from 6 manufacturers were analyzed. Twenty-six samples were found to be contaminated with AFL at 131 ng/g and 29 samples, with OTA at 110 ng/g. Ten samples contained no AFL or OTA. Ten ginseng finished products were also analyzed; 3 contained AFL at 0.1 ng/g and 4
contained OTA at levels ranging from 0.4 to 1.8 ng/g. LC/tandem mass spectrometry with multiple-reaction monitoring of 3 collisionally induced product ions from the protonated molecular ions of OTA, AFB1, and AFG1 was used to confirm the identities of the toxins in extracts
of the finished products.
Document Type: Research Article
U.S. Food and Drug Administration, 5100 Paint Branch Pkwy, College Park, MD 20740. 2:
National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20892.
Publication date: July 1, 2007
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