Europium Nanospheres-Based Time-Resolved Fluorescence for Rapid and Ultrasensitive Determination of Total Aflatoxin in Feed

Immunochromatographic (IC) assays are considered suitable diagnostic tools for the determination of mycotoxins. A europium nanospheres-based time-resolved fluorescence immunoassay (Eu-Nano-TRFIA), based on a monoclonal antibody and a portable TRFIA reader, was developed to determine total aflatoxin (including aflatoxins B-1, B-2, G(1), and G(2)) levels in feed samples. Under optimized conditions, the Eu-Nano-TRFIA method detected total aflatoxin within 12 min. It showed good linearity (R-2 > 0.985), LOD of 0.16 mu g/kg, a wide dynamic range of 0.48-30.0 mu g/kg, recovery rates of 83.9-113.9%, and coefficients of variation (CVs) of 3.5-8.8%. In the 397 samples from company and livestock farms throughout China, the detection rate was 78.3%, concentrations were 0.50-145.30 mu g/kg, the highest total aflatoxin content was found in cottonseed meal, and corn was found to be the most commonly contaminated feed. This method could be a powerful alternative for the rapid and ultrasensitive determination of total aflatoxin in quality control and meet the required Chinese maximum residue limits.