Ion mobility spectrometric monitoring of Phosdrin (R) from foliage in greenhouse

The monitoring of Phosdrin (mevinphos; insecticide) from foliage and foliag e extracts was achieved by an aspiration-type ion mobility spectrometer. Th is technique is based on ion mobility which is proportional to the molecula r weight, shape, and charge. The operation principle of the ion mobility sp ectrometer is to measure mobility distribution changes of product and react ant ions. This technique can measure positive and negative ion clusters at the same time in six different measuring electrodes. Each measuring electro de detects a different portion of the ion mobility distribution formed with in the cell's radioactive source. The pattern recognition used is based on differences in the gas profiles for different compounds. This study shows t hat an ion mobility spectrometer can be used to monitor Phosdrin from folia ge without the need for any time-consuming extraction procedure. The respon ses for Phosdrin-containing and background (control) samples were easily se parated from each other. The responses declined as a function of time in th e positive and sum response channels. In addition, the sum of the absolute values of signals at six measuring channels (sum response) were linearly pr oportional to the concentration of Phosdrin. Just before application (i.e., in background), this value was 41 bits, whereas these values were 10-fold, 11-fold, 8-fold, 6-fold, 5-fold, and 3.5-fold at the time points 4, 8, 11, 24, 50, and 72 hours after the spraying of Phosdrin.