High-Throughput Analysis of Aflatoxins in Cereals, Nuts, and Processed Products Involving Automated Immunoaffinity Cleanup and Inline HPLC-Fluorescence Detection

Background: The testing of aflatoxins (AFs) in fresh and processed foods is highly in demand to comply with trade regulations. Consequently, commercial laboratories face huge AF sample loads in food consignments. Worldwide, there is a rising interest in implementing automation to increase sample throughput in AF analysis. Objective: This study sought to evaluate the performance of an automated cleanup and HPLC analysis system for determination of regulated AFs (B1, B2, G1, G2) in rice, flattened rice, sorghum, raw and processed peanut, almond, peanut butter, and wheat-based cookies. Methods: The samples were extracted with methanol-water (80:20), diluted with Triton X-100, and subjected to automated analysis, where the cleanup step through immunoaffinity column (IAC) and HPLC-fluorescence analyses (involving postcolumn bromination-derivatization) were performed in 10 and 11min, respectively. The method was validated in all test matrices at the LOQ and higher levels. The method performance was also evaluated against a conventional workflow where cleanup and HPLC analysis were manually performed. Results: The LOQ for peanut, sorghum, rice, and flattened rice was 0.125ng/g, while it was 0.5ng/g for peanut butter, almond, and wheat-based cookies. In all matrices, the recoveries at LOQ and higher levels were satisfactory. The double-cartridge exchange system completed the analysis of similar to 96 injections in 18h. Each IAC could be reused 15 times without incurring any recovery loss. The automated system provided a better precision (RSD<9%) than the conventional workflow (RSD=12-15%). Conclusions: Because of its high-throughput nature, this method is recommended for routine analysis of AFs. Highlights: A high-throughput method is reported where cleanup and HPLC analysis of AFs were automatically performed. Each IAC could be used 15 times without any loss of recovery. The method performance was better than the conventional approach and complied with the analytical quality control guidelines.

Automated summary

This study evaluated the performance of an automated cleanup and HPLC analysis system for the detection of regulated aflatoxins in various food matrices. The results showed that the method had satisfactory performance in different food samples, providing efficient and accurate analysis with high throughput capabilities.