Determination of aldicarb, aldicarb sulfoxide and aldicarb sulfone in somefruits and vegetables using high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

An analytical method for the determination of aldicarb, and its two major m etabolites, aldicarb sulfoxide and aldicarb sulfone in fruits and vegetable s is described. Briefly the method consisted of the use of a methanolic ext raction, liquid-liquid extraction followed by solid-phase extraction clean- up. Afterwards, the final extract is analyzed by liquid chromatography-atmo spheric pressure chemical ionization mass spectrometry (LC-APCI-MS). The sp ecific fragment ion corresponding to [M-74](+) and the protonated molecular [M+K](+) ion were used for the unequivocal determination of aldicarb and i ts two major metabolites. The analytical performance of the proposed method and the results achieved were compared with those obtained using the commo n analytical method involving LC with post-column fluorescence detection (F L). The limits of detection varied between 0.2 and 1.3 ng but under LC-FL w ere slightly lower than when using LC-APCI-MS. However both methods permitt ed one to achieve the desired sensitivity for analyzing aldicarb and its me tabolites in vegetables. The method developed in this work was applied to t he trace determination of aldicarb and its metabolites in crop and orange e xtracts. (C) 2000 Elsevier Science B.V. All rights reserved.