Development of an LC-MS/MS method for the determination of pesticides and patulin in apples.
Résumé
A method for the simultaneously determination of 33 pesticides or degradation products together with patulin in apples by LC-MS/MS was developed. The principle of the method was homogenisation of the apples, extraction with ammonium acetate–acetic acid solution in methanol–water by ultrasonication, filtration and determination by LC-MS/MS. The repeatability and within laboratory reproducibility for the three spiking levels 0.02, 0.04 and 0.2 mg kg−1 were between 4-35%. In general, the repeatability and reproducibility were about 10–20%. The limits of quantification (LOQs) were between 0.01-0.14 mg kg-1. The method was used on incurred samples from parts of the ISAFRUIT project financed by the European Commission under the 6th framework. Samples were analysed at four different stages, after harvest, after storage (controlled), after water bath and after 28 days at room temperature. Pesticide residues were found at all stages, but no significant differences in the concentration were seen between the stages analysed. Only for tolylfluanid storage at room temperature in 28 days decreased the concentration significantly, only 0-6% of the original amount of tolylfluanid remained in the apples. . No patulin was found in the apple samples stored for 28 days at room temperature and no growth of P. expansum was observed on these apples. However, when the apples were inoculated with a spore suspension of P. expansum high concentrations of patulin was found
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