Abstract:To realize the situation of pesticide residues in highland barley, 11 kinds of common organophosphorus pesticides were determined simultaneously bygas chromatography - mass spectrometry (GC-MS) method. Sample preparation methods were optimized and thegC-MS analysis conditions were confirmed. The results showed that the samples were soaked in water, distilled with acetonitrile (1∶2), extracted by extraction kit containing sodium chloride and anhydrous sodium sulfate. The organic phase was recovered, and the concentrated solution was purified by purification kit QuEChERS and measured bygC-MS. 11 kinds of organophosphorus pesticides, in the range of 0.1~1.0mg/mL, showed agood linear relationship, correlation coefficient of methamidophos ≥0.99, of the other 10 compounds≥0.999, the average recoveries of standard addition was 79.25%~122.98%, and the relative standard deviation was 0.54%~5.84%.The method is simple, rapid, with less solvent and high sensitivity, and the results are accurate and reliable, which is suitable for the simultaneous determination of organophosphorus pesticides, and provides technical support for detection and control of organophosphorus pesticides in highland barley.