[Simultaneous detection of aflatoxin B1 and ochratoxin A by the dual-label time-resolved fluoroimmunoassay]

Using dual-label time-resolved fluoroimmunoassay (TRFIA) technology to establish a high sensitive method for simultaneously detect aflatoxin B1 (AFB1) and Ochratoxin A (OTA).

AFB1-HRP and OTA-BSA coated 96-well plates were taken as the solid phase antigen to compete with free AFB1 and OTA for limited anti-AFB1 polyclonal antibody or anti-OTA monoclonal antibody. Then rare earth ion Eu3+ labeled goat anti-rabbit antibody and Sm3+ labeled goat anti-mouse antibody were applied as tracers to establish AFB1/ OTA-TRFIA in dissociation enhanced fluorescence immunoassay system by using indirect competitive immunoassay.

For this method, the sensitivity of AFB1 was 0.02 microg/L with a measurement range of 0.02-100 microg/L, intra-and inter-assay CV of 3.2% and 7.3%, and an average recovery rates of 88.1%. While the sensitivity of OTA was 0.051 microg/L with a measurement range of 0.05-50 microg/L, intra-and inter-assay CV of 2.9% and 7.9%, and an average recovery rates of 89.9%. In AFB1/ OTA-TRFIA detection, the AFB1 and OTA did not interfere with each other. When samples were detected by dual-label AFB1/ OTA-TRFIA, single label AFB1-TRFIA and OTA-TRFIA at the same time, the AFB1/ OTA-TRFIA detection and AFB1-TRFIA detection for AFB1 were correlated by 0.972, while the correlation coefficient of AFB1 /OTA-TRFIA detection and OTA-TRFIA detection for OTA was 0.981, indicating that the results were consistent.

The study showed that AFB1/ OTA-TRFIA, with high sensitivity, wide measuring range, good stability, and simultaneous detection of AFB1 and OTA, could be a simple, fast and economic method.