Design of a new semi-automated cold column trapping-headspace micro solid phase extraction (CCT-HS-µSPE) device coupled with GC-MS for the extraction of pesticides in soil

In the past few years, organophosphorus compounds become one of the most widely used classes of pesticides due to their acute toxicity against a wide variety of pests[1].Different methods have been used for pesticidesdetermination[2-4]. In this work, a new semi-automated cold column trapping-headspacemicrosolid phase extraction (CCT-Hs –µSPE) device coupled to gas chromatography–mass spectrometry (GC–MS) was developed and optimized through simplex method to determine three organophosphorous pesticides in soil samples. SBA-15-NH2 as a nanoporous sorbent was used for the extraction. The proposed device improves the efficiency of the release of analytes from the matrix, facilitates the mass transfer into the headspace and significantly increases the partition coefficients of the analytes. For the efficient extraction of the pesticides (diazinon, malathion and permethrin) by the CCT-HS-µSPE system, several parameters influencing the performance of the technique, such as nature of sorbent, eluent type, elution volume, minimum and maximum cold column temperatures, extraction temperature, recycling gas flow rate, and moisture content of sample were carefully studied. The best results were obtained using SBA-15-NH2 sorbent with the sample heated at 75°C for 11.30 min and a recycling gas flow rate of 125 rpm. Under the optimized experimental conditions, linear calibration curves were obtained for the samples with regression coefficients that ranged from 0.975 to 0.977 and coefficients of variation between 4.1% to 5.6%. The method was successfully applied to the GC-MS analysis of pesticides in soil samples.