Determination of sterigmatocystin in feed by LC-MS/MS

An LC-MS/MS method is proposed for the analysis of sterigmatocystin in cereals and feed. The method is based on a solid–liquid extraction and a dilute-and-shoot approach. Accuracy and precision were established at the LOQ (1 μg kg−1); the mean overall recovery (n = 6) was 98%, with a confidence interval of 3.8% and a CV% of 3.7%. Accuracy and precision were also assessed at three other concentration levels (2.03, 5.07 and 10.14 μg kg−1; six replicates per level). The mean overall recovery (n = 24, LOQ included) was 99% with a confidence interval of 0.8% and a CV% of 1.9%. The method was then applied to 14 naturally incurred feed samples. Aflatoxin B1 was present in the range 28.7–240.1 µg kg−1, while lower concentrations of sterigmatocystin were found (0.7–2.2 µg kg−1). This method may represent a valuable choice, ensuring a high level of accuracy and precision, as well as high-throughput performance. Therefore, it meets the recent EFSA opinion recommendation in terms of availability of fast and sensitive methods (recommended LOQ = 1.5 μg kg−1) in order to increase data collection to allow for the assessment of dietary exposure.