Validation of an Analytical Method to Determine the Content of T-2 and HT-2 Toxins in Cereals and Baby Food by Immunoaffinity Column Clean-up and GC-MS

摘要

A method for the determination of T-2 toxin and HT-2 toxin in cereals and baby food was validated by collaborative study.In short, the method is as follows: A test portion of a sample is extracted with a mixture of methanol/water (80/20, v/v). This raw extract is then diluted, filtered, and applied to an immunoaffinity column. After washing and elution with acetonitrile the eluate is evaporated to dryness. T-2 and HT-2 toxins in the dry residue are then derivatised with N-methyl-N-trimethylsilyl-trifluoroacetamid (MSTFA)/ Trimethylchlorosilane (TMCS) (99/1, v/v), injected into a gas chromatograph, and detected and quantified by mass spectrometry.14 laboratories from 10 different countries were selected to participate in the collaborative study. They received 6 different test materials as blind duplicates. The test materials consisted of a blank cereal mix, two cereal mixes naturally contaminated at different levels, a blank baby food, and two baby foods naturally contaminated at different levels. Furthermore, two blank cereal mixes and two blank baby foods together with specific spiking solutions were provided for recovery determination. The sum of the mass fractions of T-2 & HT-2 after spiking were 50 µg/kg in the cereal mix, and 25 µg/kg in the baby food. Reported recoveries in the cereal mix ranged from 87 to 127% for the sum of T-2 & HT-2 with a mean value of 107%. Reproducibility relative standard deviations (RSDR) for the cereal matrix were 19% at a natural contamination level of ca. 32 µg/kg, 11% at ca. 79 µg/kg, and 12% for the spiked material at 50 µg/kg. For baby food the recovery values ranged from 91 to 127% with 116% for the mean value. The RSDR values were 23% at a natural contamination level of ca. 10 µg/kg, 15% at ca. 23 µg/kg, and 16% for the spiked material at 25 µg/kg. The Horwitz ratios (HorRat) ranged from 0.5 to 1.1.Since all these performance parameters lie well within the acceptable ranges set forth in European legislation [1] this method is suited for official food control.