Uncertainty in Determination of Quinclorac in Soil with HPLC

In order to improve the accuracy of test results, the uncertainty in determination of quinclorac in soil with HPLC was systematically calculated according to JJF 1059-1999Evaluation and expression of uncertainty in measurement. The results indicated that:1) Preparation of standard working solution, calibration of working curve and constant volume of sample solution were the major factors influencing the uncertainty; 2) The combined uncertainty was 0.00069 mg/kg and the expanded uncertainty was 0.0014 mg/kg (level of confidence of 95%, k=2) at the concentration of quinclorac in soil of 0.0236 mg/kg. The uncertainty in determination of quinclorac in soil with HPLC could be decreased by using high purity standard substance and qualified metering devices, and strictly controlling treatment procedures.