An accurate determination of fumonisins in masa can be troublesome because of difficulties often experienced in obtaining satisfactory recoveries. In this study, a new extraction method, effective both for masa and for maize and derived products, has been developed. The method extracts fumonisins using a 0.4 M phosphate buffer (PB) at pH 7.5, without any organic solvent; the purification of the extract is performed by an immunoaffinity column and the quantification by HPLC–MS/MS. The average recovery percentages were 95.5±1.9% and 96.7±2.1% for fumonisin B1 and B2, respectively. The limit of detection and of quantification for both fumonisins were 10 and 30 μg kg−1, respectively. For masa and tortillas, PB pH 7.5 gave significantly higher results when compared with AOAC and other published extraction methods; for maize flour, PB gave generally higher results, even if the difference with the other extraction methods was not always significant.
- Phosphate buffer