Determination of Residues of 5 Strong Polar Pesticides in Planting Soil by Ion Chromatography-Tandem Mass Spectrometry with Accelerated Solvent Extraction

Considering the issues of requiring derivatization processing and short chromatographic retention time on the existing methods for detection of glufosinate ammonium, glyphosine, abscisic acid, bentazone and (aminomethyl) phosphonic acid, the study mentioned by the title was conducted. The planting soil sample was taken, removed from impurities, dried by air, and sieved. An aliquot (10 g) was taken and mixed with 20 g of diatomaceous earth and 25 mL of methanol-acetone mixed solution at volume ratio of 2∶1 for accelerate solvent extraction. The extraction solution was passed through a 0.22 μm polyethersulfone filter membrane, the initial filtrate was discarded, and the subsequent filtrate was detected by ion chromatograph-tandem mass spectrometer. In chromatographic analysis, 0.1 mol·L⁻¹ sodium hydroxide solution was used for washing and separating the above 5 pesticides on the Dionex IonPac AS17 column. In mass spectrometry analysis, the negative ion mode of the electrospray ion source was used for ionization, multiple reaction monitoring (MRM) mode was used to collect data, and external standard method was used for quantification. It was shown that linear relationships between values of the mass concentration and the peak area of the 5 pesticides were kept in the range of 0.001-5.0 mg·L⁻¹, with detection limits (3S/N) of 0.012, 0.009, 0.007, 0.013, 0.005 ng·L⁻¹, respectively. Recoveries of the 5 pesticides at three spiked concentration levels were found in the range of 84.4%－103%, giving RSDs (n=5) of the determined values in the range of 1.5%-3.7%.