Detection of pesticides from liquid matrices by ion mobility spectrometry Original Research Article

The detection of different pesticide compounds from liquid matrices was achieved by aspiration ion mobility spectrometry. This technique is based on ion mobility which is proportional to the molecular weight and charge. The ion mobility spectrometer is able to measure mobility changes of product ions as well as mobility changes of reactant ions. In the ion mobility spectrometer used, it is possible to measure positive and negative ion clusters at the same time in six different electrodes. Each measuring electrode detects a different portion of the ion mobility distribution formed within the cell’s radioactive source. The pattern recognition used is based on differences in the gas phase profiles of the different compounds. The results of this study reveal that the ion mobility spectrometer MGD-1 can also be used to measure pesticides even from liquid matrices. On the basis of projection calculation, the responses for 2-propanol (= background) and pesticide compounds were easily separated from each other. The greatest responses for pesticides were seen in the 2nd positive channel. Correspondingly, only minor background signals were measured in the 1st and 2nd positive channels. The detection limits of pesticides were at ng or μg levels. The sensitivity of detection of the ion mobility spectrometer for different pesticides decreased in the order: diazinon, aldicarb, dimethoate and parathion. In comparison with the traditional ion mobility spectrometric technique, the main advantages of this aspiration technique are its fast response, high sensitivity, real time vapor monitoring, straightforward maintenance and low cost. In addition, the cell tolerates high chemical concentrations and still recovers quickly.