Direct analysis in real time mass spectrometry for the rapid identification of four highly hazardous pesticides in agrochemicals

Abstract

Direct analysis in real time (DART) is a new ion source technique, which is conducted in the open air under ambient conditions, applied to the rapid and direct analysis of any material (gases, liquids, and solids) with minimal or no sample preparation. In order to take advantage of the capacity of DART mass spectrometry for the real-time analysis of hazardous ingredients in commercial agrochemicals, a pilot study of rapid qualitative determination of hazardous pesticides was performed. Highly hazardous pesticides were identified by DART ionization coupled to a single-quadrupole mass spectrometer (DART-MS). Acetonitrile was chosen for dissolving samples prior to the analysis. Samples were analyzed by this technique in as little as 5 s. Phorate, carbofuran, ethoprophos and fipronil were be detected directly from commercial agrochemicals. The ionization-related parameters (DART temperature, grid voltage and MS fragment) of these compounds were optimized to obtain highly response. Isotope patterns were taken into consideration for qualitative identification. Relative standard deviations (RSDs, n = 5) of 2.3-15.0% were obtained by measuring the relative abundance of selected isotopes. This study showed that DART-MS technology was able to qualitatively determine the existence of highly hazardous pesticides in commercial pesticide formulations. It is suggested that this technology should be applied for routine monitoring in the market.