New method based on Solid Phase Microextraction and Multidimensional gas chromatography-mass spectrometry to determine pesticides in strawberry jam

Although, the use of pesticides is necessary in agriculture to prevent crops destruction and to avoid the attack to leaves and stems of the plants, which cause quality defects of fruits and yield reduction, the control of pesticide is important in order to guarantee human safety. In the present study, a new method based on the use of solid-phase microextraction (SPME) followed by multidimensional gas chromatography-mass spectrometry (MDGC-MS) analysis was developed to detect pesticides in strawberry jam. Commercial and home-made jams as well as spiked non-spiked samples were included in the study. The method was validated by analysing commercial jam samples spiked with a pesticide mixture (ie, standard Mix 101). As a result, Relative Standard Deviation estimated from five replicates, was always below 16%. Limit detection values varied from 0.11 to 0.42 ng/kg on the first dimension and from 0.013 to 0.093 ng/kg on the second dimension. These levels are considerably lower than the Maximum Residue Levels established for strawberry pesticides by EU Regulations. Also, the matrix effect of the strawberry jam on the effectiveness of the SPME extraction was evaluated. The data presented demonstrate that the method proposed is capable of detecting reliably very low concentrations of pesticides in strawberry jams between 0.013 and 0.093 ng/kg. Additional advantages of the method are its repeatability, rapidity, simplicity, selectivity and environmental friendly nature.