Analysis of Perchlorate in Food Samples of Plant Origin Applying the QuPPe-Method and LC-MS/MS

-1This study reports about how to integrate the environmental contaminant perchlorate into the QuPPe multiresidue method for the analysis of polar pesticides. Perchlorate, along with a number of polar pesticides, was extracted with acidified methanol. The extracts were filtered and subjected to liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). 18O-labeled perchlorate was used as internal standard. The assay was validated for apple and barley matrix at 0.01 and 0.1 mg/kg, showing average recoveries between 93 % and 108 % and relative standard deviations (RSDs) between 2.2 % and 5.0 %. Up to now, we have analyzed 350 conventionally and 78 organically grown food samples (vegetables, fruits, cereals, legumes, mushrooms and processed foods) from the local market for perchlorate. Perchlorate could be detected in 66 (19 %) of the conventional samples and in two (2.6 %) of the organic samples; in six samples the provisional maximum tolerable daily intake (PMTDI) of 0.01 mg/kg bodyweight was exceeded.