Feasibility of capillary liquid chromatography–microchip-atmospheric pressure photoionization–mass spectrometry for pesticide analysis in tomato Original Research Article

A new and sensitive analytical method, using capillary liquid chromatography (capLC) with a microfabricated heated nebulizer chip for atmospheric pressure photoionization and tandem mass spectrometry (μAPPI–MS/MS), was developed for the analysis of selected carbamate pesticides in a tomato matrix. The performance of the instrumental method was evaluated, using seven pesticides, namely oxamyl, methomyl, aldicarb, carbofuran, pirimicarb, thiocarb, and ditalimfos. The limits of detection achieved with the capLC–μAPPI–MS/MS method in the positive ion mode were low, ranging from 0.25 ng mL−1 for pirimicarb to 5 ng mL−1 for oxamyl and methomyl, corresponding to 5 and 0.25 μg kg−1 for tomato samples, respectively, which are clearly below the maximum residue limits for them in fruits and vegetables. The repeatability of the instrumental method ranged from 2.9 to 13.9% (RSD) at a low (0.05 μg mL−1) concentration level. An adequate linearity (r2 = 0.984–0.999) at a concentration range from 0.005 to 5.0 μg mL−1 was observed for all pesticides. The results obtained show that the capLC–μAPPI–MS/MS method developed could be used for the analysis of selected pesticides from tomato.