Simple and rapid determination of N-methylcarbamate pesticides in citrus fruits by electrospray ionization tandem mass spectrometry

We developed a new analysis method for the N-methylcarbamate pesticides in citrus fruits. The pesticides were extracted from citrus fruits with cyclohexane, the extract was cleaned up by gel permeation chromatography (GPC) and determined by flow-injection electrospray ionization (ESI)-MS/MS. The new method is simple and rapid, and allows simultaneous determination of seven N-methylcarbamate pesticides in citrus fruits. The average recoveries from citrus fruits fortified at the level of 0.5 ppm ranged from 66.8 to 129.2% with the coefficients of variation ranging from 0.5 to 6.2% for intra-day (n = 5 x 3 days) and from 4.1 to 15.9% for inter-day (n = 15). The method is considered to be satisfactory for the monitoring of the carbamate pesticides residues in citrus fruits, suggesting that the present method is applicable to the other pesticide residues in foods such as organochlorine and organophosphorous pesticides. (C) 2003 Elsevier Science B.V. All rights reserved.