Simultaneous determination of eight pesticide residues in cowpeas by GC-ECD

Abstract

A sensitive and effective method, using gas chromatography (GC) and an electron capture detector (ECD), for the simultaneous quantitative determination of bifenthrin, chlorothalonil, cyfluthrin, cypermethrin, difenoconazole, fenvalerate, procymidone and pyridaben residues in cowpea was developed and validated. The method involved extracting with acetonitrile, purification with a graphitized carbon black/amino solid phase extraction cartridge, and then determining by GC- ECD. Recovery studies were carried out at three spiked levels (0.01, 0.1 and 0.5 mg/kg). The average recoveries at the three spiked levels ranged from 76.6 to 107.0% with relative standard deviations in the range of 1.2-5.6% for all analytes. The quantification limit was 0.01 mg/kg for each pesticide and was less than or equal to the relevant MRLs set by China, the Codex Alimentarius or the European Union. The developed analyzing method was convenient, time and cost saving, environment-friendly and readily available than the traditional methods.