Multi-class determination of pesticides and mycotoxins in isoflavones supplements obtained from soy by liquid chromatography coupled to Orbitrap high resolution mass spectrometry

- Pesticides and mycotoxins have been determined in isoflavones supplements from soy.
- More than 250 toxic substances have been analyzed by LC-Orbitrap-MS/MS.
- A dilute and shoot procedure was used for the extraction of the compounds.
- Six pesticides and two mycotoxins were found in the analyzed samples.

A methodology has been developed to identify and quantify 257 toxic substances (including pesticides and mycotoxins) in diverse isoflavones supplements obtained from soy. Two different extraction procedures were compared, QuEChERS and “dilute and shoot”. The best results were observed when the “dilute and shoot” methodology was applied using acetonitrile acidified with formic acid (1% v/v) as extraction solvent followed by a clean-up step with Florisil cartridges. Validation of the method was carried out evaluating trueness, repeatability and intermediate precision, obtaining recoveries between 70 and 120% with relative standard deviation (RSD) values lower than 20%. Limits of detection and quantification were below 5 and 10 μg kg−1 respectively. The validated methodology was applied to the analysis of real samples, finding pesticides such as flutolanil (12.2 μg kg−1) and etofenprox (48.2 μg kg−1). Regarding mycotoxins, aflatoxin B1 (8.2-17.1 μg kg−1) and aflatoxin G2 (6.4 μg kg−1) were detected.