Abstract: Ultrasonic extractionhigh performance liquid chromatography was adopted to determinate the mass concentration of nitrification inhibitor—nitrapyrin in different soil types using the Agilent SBC18 (150 mm×4.6 mm, 5.0 μm) chromatographic column under the condition of optimizing the best volume ratio and the flow rate of the mobile phase. The results show that the best extracting effect is that the soil sample is disposed by the organic solution of ethanol for three times continuously followed by organic filter membrane to purify, then chromatographic column of Agilent SBC18 is separated under the condition of the mobile phase being V(acetonitrile)∶V(water)=4, and completing within 10 min at the flow rate of 0.8 mL/min. There is a significant linear relationship between the mass concentration of nitrapyrin and the peak area in the range of 0—75 mg/L (R2=0.999 8, p<0.01). The detection limit of nitrapyrin in blank soil is 0.42 mg/L. The recovery rate of nitrapyrin for different mass concentrations and dosage forms in meadow black soil, chernoze and aeolian soil is 82.44%--91.66% after 24 h of addition with the standard deviation of 1.34—5.04 and the coefficient variation of 0.02—0.06.

Key words: soil, nitrification inhibitor, nitrapyrin, ultrasonic extraction, high performance liquid chromatography （HPLC）