Optimization and Validation of an Analytical Method for the Determination of Free and Hidden Fumonisins in Corn and Corn Products by UHPLC-MS/MS

Fumonisins are mycotoxins and corn has been considered the foodstuff presenting the highest contamination levels by these compounds. In recent years, the presence of hidden fumonisins in corn and corn products has aroused the interest of public health authorities. The aim of this study was to optimize and validate a simple and fast analytical method for the determination of free and hidden fumonisins in corn and corn products by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Several sample treatment methods were assessed for free fumonisins determination, and a method using rapid shaking and sonication, followed by extract dilution without the need for a clean-up step was selected for validation. Hidden fumonisins determination was based on the hydrolyzed forms (HFB1 + HFB2) obtained after sample alkaline hydrolysis. The alkaline hydrolysis efficiency was optimized, with a final selected shaking time of 60 min. Satisfactory recoveries were obtained for the target mycotoxins in the validated method, ranging from 89 to 110%, with relative standard deviations lower than 14%. Linearity was confirmed for the calibration curves at the assessed concentration ranges. The method sensitivity was considered adequate, with limits of quantification ranging from 0.4 μg kg −1 to 17.8 μg kg −1 . The proposed analytical method was applied satisfactorily to the analysis of real samples, being considered attractive for routine analyses.