Eu3+‐labeled IgG‐based time‐resolved fluoroimmunoassay for highly sensitive detection of aflatoxin B1 in feed

BACKGROUND Aflatoxin B1 (AFB1) is a kind of toxic and carcinogenic mycotoxin. A time‐resolved fluoroimmunoassay (TRFIA) was established for quantitative detection of AFB1 in feed using Eu3+‐labeled IgG as tracer. RESULTS Monoclonal antibody (McAb) against AFB1 (9B11‐D7) was prepared through immunization and cell fusion and was identified as high affinity, specificity and sensibility by enzyme‐linked immunosorbent assay (ELISA). The 50% inhibition value (IC50) was 0.81 ng mL−1, the limit of detection (LOD) was 0.10 ng mL−1 and detection range was 0.10–3.94 ng mL−1. Goat anti‐mouse immunoglobulin G (IgG) was modified by Eu3+‐DATT, generating Eu3+‐labeled IgG. Under optimal assay conditions, TRFIA was shown to be highly sensitive and specific in detection of AFB1. The IC50 and LOD were 94.73 pg mL−1 and 3.55 pg mL−1, respectively, and detection range was 3.55–1.11 × 103 pg mL−1. Cross‐reactivity with AFM1, AFB2, AFG1 and AFG2 was 31.26%, 37.6%, 127.46% and 35.74%, respectively, but zero with other analogues. In determination of AFB1 spiked in feed sample, TRFIA showed high accuracy and precision. The average recoveries ranged from 93.71% to 97.80%, and coefficient of variation was 1.25–3.73%. Good correlation between TRFIA and HPLC was demonstrated for determination of AFB1 in feeds, confirming the reliability of the developed method. CONCLUSION The developed TRFIA exhibited good potential for employment in the ultrasensitive detection of AFB1 in feed and could be used to determine total aflatoxins. © 2017 Society of Chemical Industry