双色谱柱双FID顶空气相色谱法测量乙醇 浓度的一致性评价

目的 研究双色谱柱双FID检测器顶空气相色谱法（双柱双检法）测量乙醇浓度的一致性，探讨不同一致性评价方法应用价值，为司法鉴定中涉嫌“醉驾”案件准确检测乙醇浓度提供理论依据。方法 配置浓度为80mg/100ml 乙醇溶液和4mg/100ml叔丁醇的混合样。使用自动进样器进样，然后用配备色谱柱和双FIDs的HS-GC分别分析样品。共进行了20次试验，分别计算FID-1和FID-2组的乙醇浓度。采用配对 t 检验、Pearson相关分析、组内相关系数、Bland- Altman 法、ATE/LER区域法等，对两组乙醇检测结果进行一致性评价。结果 FID-1组乙醇浓度为（79.57±1.65） mg/100ml，RSD为2.07%；FID-2组为（81.42±1.33） mg/100 ml，RSD为1.63%。配对 t 检验: t =-7.69（ P <0.001）；Pearson相关系数: r =0.757（ P <0.001）；组内相关系数: ICC =0.739（ P <0.001）；Bland-Altman 法显示，95%的点均落在一致性限内；ATE/LER区域法显示，100%点落在ATE区域，无点落在LER区域。结论 推荐联合使用Bland- Altman图分析法、ATE/LER区域法和组内相关系数作为双柱双检法检测样本中乙醇浓度的一致性评价方法。 双柱双检法测量乙醇浓度的一致性良好。但还应结合测量不确定度等方面对FID-1、FID-2的结果进一步研究。

Consistency evaluation of alcohol concentration measured by HS-GC with dual chromatographic columns and dual flame ionization detectors

Objective To study the consistency of alcohol concentration (AC) measured by head-space gas chromatography (HS-GC) with dual chromatographic columns and dual flame ionization detectors (FIDs), to explore the value of different methods in the consistency evaluation and to provide a theoretical basis for accurate determination of AC in suspected "driving after drinking alcohol" cases in forensic science.]Methods 80 mg / 100ml ethanol solution and 4mg / 100ml TERT butanol were mixed as test samples. An auto-sampler was used to inject samples. Then the samples were separately analyzed by HS-GC equipped with dual chromatography column and dual FIDs. A total of 20 tests were conducted, and the AC of FID-1 and FID-2 groups were calculated respectively. The paired-samples ttest, Pearson’s correlation coefficient, intraclass correlation coefficient (ICC), Bland-Altman analysis and the Allowable Total Error (ATE)and Limits for Erroneous]Results (LER) zones were used to evaluate the consistency of AC between the two groups.]Results The AC of FID-1 group was (79.57±1.65) mg/100ml with the RSD of 2.07%. The AC of FID-2 was (81.42±1.33) mg/ 100ml with the RSD of 1.63%. The paired-samples ttest showed t=-7.69 (P<0.001). Pearson’s correlation coefficient showed r=0.757 (P<0.001). The intraclass correlation coefficient showed ICC=0.739 (P<0.001). The Bland-Altman analysis showed that 95% of the values fell within the Agreement of Limit (LoA). 100% of the values fell in the ATE zones and no values fall in the LER zones.]Conclusion In combination with Bland-Altman analysis, ATE/LER zones and ICC are recommended as an ideal method for consistency evaluation of AC. The results of FID-1 showed good consistency with FID-2 in AC measurement. However, the results of FID-1 and FID-2 should be further studied in combination with uncertainty of measurement.