Residue dissipation and processing factor for dimethomorph, famoxadone and cymoxanil during raisin preparation

• Simultaneous analysis of famoxadone, cymoxanil and dimethomorph residues in grape and raisin.
• Effect of processing on dissipation of residues during raisin preparation evaluated.
• Processing factors of famoxadone, cymoxanil and dimethomorph estimated.
• Safety evaluation of market samples of Indian raisin reported.

A method was validated for the simultaneous analysis of the residues of dimethomorph, famoxadone and cymoxanil in grape and raisin matrix by ethyl acetate based extraction and liquid chromatography tandem mass spectrometric analysis. Field studies were conducted to evaluate the dissipation rate kinetics and processing factor (PF) for these pesticides during raisin making. Residue data during the drying process were best fitted to 1st + 1st order rate kinetics with half-life ranging between 8–9 days for dimethomorph, 12–13 days for famoxadone and 9–10 days for cymoxanil at single dose (SD) and double dose (DD), respectively. PF values calculated were 1.03 and 1.14 for dimethomorph, 1.95 and 2.09 for famoxadone, and 1.99 and 1.35 for cymoxanil at SD and DD, respectively. PF value >1 indicates concentration of the residues during raisin making. The residues of detected pesticides in market samples of raisins were devoid of any risk of acute toxicity related to dietary exposure.