测定工作场所空气中氰化氢试验条件的改进

Improvement of Experimental Conditions for Detecting Hydrogen Cyanide in Workplace Air

目的工作场所空气中氰化氢的国家标准检验方法由于p H不合适导致出现样品显色异常现象,经过对异烟酸—巴比妥酸、缓冲溶液的配制以及操作的一些改进后,取得满意结果。方法对原方法的显色剂、缓冲液等试剂进行适当的改进后,采用异烟酸—巴比妥酸分光光度法测定工作场所中氰化氢。结果方法的最低检出限为0.05μg/m L,最低检出质量浓度为0.05 mg/m^3（以采集2 L空气样品计）,测定范围0.05~2μg/m L,回归方程为y=0.332x＋0.0169,相关系数r=0.9998;加标样品（低、中、高3个质量浓度分别为0.20、0.70和1.20 mg/m^3）相对标准偏差（RSD）分别为4.5%、1.7%和1.3%。结论经过改进后的方法实验显色正常,结果稳定,满足测定要求。

Objective To improve the national standard method for the detection of hydrogen cyanide in the air of workplace. Method Because the abnormal color reaction of samples was caused by improper p H value,the preparation of isonicotinic acid- barbituric acid,the chromogenic agent,and the buffer reagent of original method were improved. The concentration of hydrogen cyanide in the air of workplace was detected by spectrophotometry.Results The minimum detection limit of the method was 0. 05 μg / m L; the lowest detection concentration was0. 05 mg / m^3（ in 2 L air samples）; the range of detection was in 0. 05 ~ 2 μg /m L; the regression equation of standard curve was y = 0. 332 x ＋ 0. 0169; and the correlation coefficient was r = 0. 9998. The relative standard deviation（ RSD） of standard addition at low,medium and high levels（ 0. 20 mg /m^3,0. 70 mg /m^3 and 1. 20 mg / m^3） were4. 5%,1. 7% and 1. 3%,respectively. Conclusion The color reaction of sample was normal after the method being improved,and the results were stable and satisfactory.