短时间采样溶剂解吸气相色谱法测定工作场所空气中苯的不确定度评价

Uncertainty Evaluation on Gas Chromatography Determination of Benzene in the Air of Workplace With Short Time Sampling and Solvent Desorption

目的建立短时间采样溶剂解吸-气相色谱法测定工作场所空气中苯的不确定度分析方法,以评价测定结果的质量,找出主要影响因素。方法根据标准GBZ/T 160.42-2007短时间采样溶剂解吸-气相色谱法测定工作场所空气中苯,建立不确定度的数学模型,系统分析、计算不确定度各分量。结果采用溶剂解吸-气相色谱法测定工作场所空气中苯,当苯浓度为4.14 mg/m3,其扩展不确定度为0.40 mg/m3(k=2)。其中采样体积、采样效率,解吸效率、标准溶液配制和标准系列测定对测量相对标准不确定度贡献较大。结论此方法评价短时间采样溶剂解吸-气相色谱法测定工作场所空气中苯的不确定度,适用于评估测定结果误差的主要来源。

Objective To establish a method for the uncertainty analysis in gas chromatograghy（GC） determination of benzene in the air of workplace with short time sampling and solvent desorption so as to assess the quality of the results and find out the main influencing factors. Methods A mathematical model for uncertainty of GC determination of benzene in the air of workplace with short time sampling and solvent desorption according to the national standard GBZ/T 160.42 -2007 was established to systematically analyze and calcu- late each component of the uncertainty. Results In GC determination of benzene in the air of workplace with short time sampling and solvent desorption, when the concentration of benzene was 4. 14mg/m 3, the expand- ed uncertainty was 0. 40mg/ms （ k = 2）. The sampling volume, sampling efficiency, desorption efficiency, preparation of standard solutions and determination of the standard series contributed the most to the relative standard uncertainty of determination. Conclusion The method is applicable to evaluate the main causes of the result error in the uncertainty evaluation of GC determination of benzene in the air of workplace with short time sampling and solvent desorption.