Behaviour of some organophosphorus pesticide residues in thyme and stinging nettle tea during infusion process

Summary In order to investigate dissipation behaviour of fenitrothion, dimethoate, chlorpyrifos and pirimiphos-ethyl during infusion process, pesticide-free dried thyme and stinging nettle leaves were spiked with the pesticides. Infusions were prepared according to the usual process of infusion preparation. The effect of infusion process on the transfer of the pesticides from the spiked herbs leaves into brew was examined at intervals of 5, 10, 15 and 20 min. Residues were determined using gas chromatograph equipped with a flame ionization detector. The decrease in pesticide levels during infusion was found to be statistically significant (P < 0.05). Transfer of residues decreased considerably with infusion time. The carryover of the residues of dimethoate, which has the highest water solubility, into the infusions was the greatest. Satisfactory relationships were found between water solubility (Ws) and partition coefficient (Kow) of the pesticides with the transfer of pesticides to brewed teas.