Determination of ochratoxin A at part-per-trillion level in Italian salami by immunoaffinity clean-up and high-performance liquid chromatography with fluorescence detection.

A fast high-performance liquid chromatography method has been devised for the determination of ochratoxin A (OTA) in Italian salami in the low part-per-trillion (pg/g) level. The samples were extracted with ethyl acetate and purified by immunoaffinity column (IAC). The IAC eluate could be directly injected or previously concentrated 10-fold. Recovery at 0.5 and 1 ng/g was 77 +/- 4%. The between-day coefficient of variation measured over 5 days on samples spiked at 1 ng/g was 8%. The developed method required a relatively small volume of non-halogenated organic solvent and the whole procedure was simpler and faster compared to other existing procedures. The limit of detection was 0.06 ng/g that could be even lowered using a preconcentration step. A total of 30 salami samples were analysed using this procedure; the most contaminated sample was found to have OTA concentration at 0.4 ng/g level.