Acetonitrile: the better extractant for the determination of T-2 and HT-2 toxin in cereals using an immunoaffinity-based cleanup?

The complete extraction of the analytes is the most important item during the analysis of matrix samples. Within the discussion, which of both extractants—aqueous methanol or aqueous acetonitrile—is the best for the extraction of the mycotoxins T-2 and HT-2, a recently published work pointed out, that the latter one resulted in incorrect high toxin concentrations. Due to water absorption of dry samples and salting out effects, a phase separation of the extractant occurs and the toxins accumulate in the organic layer. Based on these results, investigations were performed by comparing and evaluating the extraction efficiency of methanol/water and acetonitrile/water—the most frequently used extractants for T-2 and HT-2 toxin. Therefore, a reliable and routine capable method combining the extraction with acetonitrile/water and a cleanup with immunoaffinity columns was necessary. Due to the sensitivity of the antibodies against acetonitrile, the cleanup of extracts containing acetonitrile was critical. A modified workup based on the investigated antibodies’ tolerance of 5% of acetonitrile was established. The method was validated according to common guidelines (linearity, limit of detection/limit of quantitation, accuracy, method precision, recovery). Especially for more complex matrices a better extraction efficiency with acetonitrile/water was obtainable, simple or unprocessed matrices resulted in identical toxin concentrations independent from extraction solvent. [ABSTRACT FROM AUTHOR]