工作场所空气中甲苯溶剂解吸气相色谱法测定的不确定度评定

Evaluation of Uncertainty in Determining Toluene in The Air of Workplace by Solvent Desorption Gas Chromatography

目的建立工作场所空气中甲苯的溶剂解吸气相色谱法测定的不确定度评定方法,通过控制这些因素提高检测结果的置信度和准确性。方法依据中华人民共和国国家计量技术规范JJF1059-1999《测量不确定度评定与表示》和中国金属学会推荐的技术和方法CCM010100-2006《化学仪器分析测量结果不确定度评定导则》。结果甲苯不确定度主要来源:①测量重复性的不确定度;②标准溶液配制过程的不确定度;③标准曲线的变动性的不确定度;④采样过程的不确定度;⑤解吸效率的不确定度;⑥样品解吸的不确定度。取包含因子k=2,扩展不确定度为U=1.7540×2≈3.51mg/m3。结论该不确定度评定方法对甲苯的溶剂解吸气相色谱法检测过程的质量控制意义十分重大,是提高检测结果的置信度和准确性的保证。

[ Objective] To establish the evaluation method of uncertainty in determining toluene in the air of workplace by solvent desorption gas chromatography, and to identify the main factors which can make effects on the test results and can be controlled to improve the confidence level and accuracy. [ Methods ] Experiments were based on the People~ Republic of China National Metrology technical specifications JJF1059 -1999 ＂Evaluation and Representation of Measurement Uncertainty,＂ and the Chinese Society for Metals recommended techniques and methods CCM010100 -2006 ＂ Uncertainty Evaluation Guidelines in Measuring The Results by Chemical Analysis Instrumentation ＂ [ Results] The main source of toluene uncertainty： （1） The uncertainty of measurement repeat- ability; （2）Uncertainty of standard solution preparation process; （3） The standard curve of changes in uncertainty; （4）Uncertainty of sampling process, （5） Uncertainty of desorption efficiency, （6） Uncertainty of desorption sampling. To check the coverage factor k = 2, expanded uncertainty was U =1.7540×2≈3.51mg/m3 [ Conclusion ] The uncertainty evaluation method, which has great sig- nificance in quality control of toluene determination by solvent desorption gas chromatography, can improve the confidence level and accuracy of test results.