Development of sensitive and rapid analytical methodology for food analysis of 18 mycotoxins included in a total diet study.

A rapid and sensitive method for the determination of 18 mycotoxins in 24 different food matrices has been developed and validated. With the exception of beverages and oil samples, a simple extraction with acetonitrile:water 80:20 (0.1% formic acid) was applied. Fruit juice, wine and beer samples were simply diluted with water containing 0.1% formic acid. Oil samples were partitioned with acetonitrile/hexane in order to remove fats. Analyses were made by ultra-high performance liquid chromatography (UHPLC) coupled to tandem mass spectrometry with triple quadrupole. Validation was carried out in all selected matrices using blank samples spiked at two analyte concentrations. Extraction recoveries between 70 and 120% and relative standard deviations lower than 20% were obtained for the wide majority of analyte-matrix combinations. Matrix-matched calibration was used for a correct quantification in order to compensate for matrix effects. Limits of quantification were lower than maximum permitted levels for every regulated mycotoxin-matrix combination. The acquisition of three SRM transitions per compound allowed the unequivocal confirmation of positive samples, supported by the accomplishment of ion intensity ratios and retention time when compared with reference standards. The developed methodology was applied to the analysis of 240 samples within a total diet study performed at Comunidad Valenciana (Spain). The most frequently found mycotoxins were deoxynivalenol, fumonisin B1, ochratoxin A and zearalenone at low μg kg(-1) levels, mainly in bread, breakfast cereals and beer.