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 B1, B2, G1 and G2 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 R2 > 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 © 2009 John Wiley & Sons, Ltd.