Eu 3+ ‐labeled IgG‐based time‐resolved fluoroimmunoassay for highly sensitive detection of aflatoxin B 1 in feed

BACKGROUND Aflatoxin B 1 (AFB 1 ) is a kind of toxic and carcinogenic mycotoxin. A time‐resolved fluoroimmunoassay (TRFIA) was established for quantitative detection of AFB 1 in feed using Eu 3+ ‐labeled IgG as tracer. RESULTS Monoclonal antibody (McAb) against AFB 1 (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 (IC 50 ) 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 Eu 3+ ‐DATT, generating Eu 3+ ‐labeled IgG. Under optimal assay conditions, TRFIA was shown to be highly sensitive and specific in detection of AFB 1 . The IC 50 and LOD were 94.73 pg mL −1 and 3.55 pg mL −1 , respectively, and detection range was 3.55–1.11 × 10 3  pg mL −1 . Cross‐reactivity with AFM 1 , AFB 2 , AFG 1 and AFG 2 was 31.26%, 37.6%, 127.46% and 35.74%, respectively, but zero with other analogues. In determination of AFB 1 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 AFB 1 in feeds, confirming the reliability of the developed method. CONCLUSION The developed TRFIA exhibited good potential for employment in the ultrasensitive detection of AFB 1 in feed and could be used to determine total aflatoxins. © 2017 Society of Chemical Industry