Product-specific Sample Clean-up and HPLC Analysis of Aflatoxins for a Dietary Product

Introduction - A sample clean-up procedure has been developed for a complex dietary ingredient, Unigen Inc. (Lacey, WA, USA) product A (a proprietary mixture of Scutellaria baicalensis and Acacia catechu extracts), for the determination of aflatoxins by HPLC. Objective - To develop an appropriate sample specific clean-up procedure that removes interferences from the sample for the determination of total aflatoxins 13, 13, G, and G, at or lower than 20 ppb by HPLC. Methodology - The sample specific clean-up procedure was developed based on the modification of AOAC method 990.33. Results - Coextract interferences were removed with the clean-up procedure. The recovery of total aflatoxins was 70% with RSD about 2%; the LOD and LOQ were 1.6 and 5.2 ppb, respectively, for total aflatoxins; the linearity R-2 > 0.99. None of the samples tested showed the presence of detectable aflatoxins. Conclusion - The modified clean-up method was effective to remove coextract interferences from Unigen product A samples. Copyright (c) 2009 John Wiley & Sons, Ltd.