Simple phosphate buffer extraction for the determination of fumonisins in masa, maize and derived products

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.