硫化物标定方法的改进

对HJ/T 200-2005中硫化物标定方法进行了改进。改进后的方法通过限制碘溶液加入后的硫酸加入速度,成功地控制了碘与硫化物的歧化副反应的进度,找到了影响硫化物标定方法准确度和精密度的因素。在乙酸锌的加入量为10 mL,碘溶液加入后的静置时间为0 s,硫酸的加入量为8 mL,反应时间为5 min的实验条件下,测定结果的相对标准偏差为0.45%~1.33%(n=6),样品的加标回收率为97.1%~99.6%。对改进后的方法进行t检验,没有显著的系统误差,该方法具有良好的准确度和精密度。

Improvement of Sulfide Calibration Method

The method of sulfide calibration in HJ/T 200-2005 was improved.By limiting the adding rate of sulfuric acid after adding iodine solution,the improved method successfully controlled the progress of the disproportionation side reaction between iodine and sulfide,and found the factor that affected the accuracy and precision of sulfide calibration method.Under the experimental conditions of adding 10 mL zinc acetate,the standing time was 0 s after adding iodine solution,the volume of sulfuric acid added was 8 mL and reaction time was 5 min,the relative standard deviation of the measured results was 0.45%-1.33%(n=6),and the standard recovery of the samples was 97.1%-99.6%.There is no significant systematic error in the t-test of the improved method,and the method has good accuracy and precision.