spiked calibration curve: a valid method for simultaneous analysis of pesticides in melon using gas chromatography mass spectrometry (gc/ms)

recently, with increasing public awareness of food safety, developments of some valid and rapidly analytical methods are required for the determination of residual pesticides in crops.this study was conducted on validation of a reliable, accurate and precise method for multi analysis of pesticides residue in melon as a main fruit in iranian food basket. a reliable, and valid method based on spiked calibration curves and modified quechers sample preparation was developed for determination of 12 pesticide residues in melon by gas chromatography mass spectrometry (gc/ms). the interested pesticides are, diazinon, dimethoate, chlorothalonil, pirimicarb, chlorpyrifos-methyl, metalaxyl, α-endosulfan, ß -endosulfan, permethrin 1, 2 and fenvalerate 1, 2 that are belonged to different chemical groups of pesticides.  triphenylmethane (tpm) is used as internal standard. use of spikedsamples for constructing the calibration curve substantially reduced adverse matrix-related effects. the recovery of pesticides at 3 concentration levels (n=3) was in range of 79.8-97.6%. the method was proved to be repeatable with rsd lower than 20%. the limits of quantification for all pesticides were the recoveries and repeatabilities were in accordance with the criteria set by sanco guideline (commission of the european communities, 2006). using spiked samples for preparation of calibration curves is a sensitive, selective, rugged, rapid and accurate method in pesticides analysis.