Preparation and application of immunoaffinity column coupled with dcELISA detection for aflatoxins in eight grain foods

This paper described a reliable and simple analytical method for the determination of aflatoxins (AFB(1), AFB(2), AFG(1), AFG(2)) in cereals, peanuts, vegetable oils and fermented foods like beer, soybean sauce and soybean paste based on immunoaffinity column (IAC) cleanup coupled with direct competitive enzyme linked immunosorbent assay (dcELISA) detection and confirmed by ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Under the optimized conditions, the home-made IAC capacity was 293, 60, 220 and 45 ng/mL gel for AFB(1), AFB(2), AFG(1) and AFG(2), respectively. Eight grain foods were pretreated with IAC, and then the extracts were detected by the dcELISA. The results showed that the recoveries of IAC-dcELISA ranged from 71.5% to 119.8% (relative standard deviations <= 16.67%) that were higher than dcELISA without IAC cleanup procedure by at least 30% on average, indicating that the matrix interference of different samples could be alleviated via the pretreatment of IAC, especially for fermented foods. The developed method was also confirmed by UHPLC-MS/MS with electrospray interface in positive mode using multiple reaction monitoring. In conclusion, this assay could be used as an effective analytical method for the determination of aflatoxins in complex grain foods. (C) 2016 Elsevier Ltd. All rights reserved.