Abstract: Ochratoxin A (OTA) in samples was captured and concentrated by immunoaffinity chromatography (IAC) and detected by enzyme-linked immunosorbent assay (ELISA). The anti-OTA monoclonal antibodies used in IAC and ELISA came from different clone strains, belonging to different idiotypes, and there were differences between their selectivity for binding to OTA targets. The combined use of IAC and ELISA could effectively filter out the interference from OTA analogues, thus improving the specificity and sensitivity of immunological analysis. The limit of detection (LOD) for OTA in spiked samples was 0.2 ng/g, the quantification limit was 0.4 ng/g, and the average recovery was 75.9%. Although the recovery of the IAC-ELISA method was slightly lower than that of ELISA, the sensitivity was increased by 60 times. For 49 real samples, the proportion of samples that tested positive by this combined method was 100% consistent with the result of the national standard method, with a missed detection rate of 0%. Therefore, the developed method exhibited significant advantages in accuracy. As a comprehensive immunoassay, this method does not require any large-scale instruments or equipment, and has no strict requirement on the operating environment, thereby making it easy for grassroot laboratories to analyze OTA in samples.

Key words: immunoaffinity chromatography; enzyme-linked immunosorbent assay; detection; ochratoxin A