HS-GC内标曲线法测定碘酊中乙醇含量及其不确定度评估

Determination and Uncertainty Evaluation of Ethanol in Iodine Tincture by HS-GC

目的建立顶空气相色谱法(HS-GC)测定碘酊中乙醇含量的方法,并探讨不确定度评估方法。方法采用HS-GC内标曲线法测定乙醇含量,以正丙醇为内标物,Thermo TG-WAXMS毛细管柱(30.0m×0.25mm,0.5μm),FID检测器;分析测量过程不确定度的来源,建立数学模型,计算合成标准不确定度和扩展不确定度。结果乙醇在0.125~1.50ml·L^(-1)浓度范围内线性关系良好,平均加样回收率为100.07%;扩展不确定度为1.71%(k=2),乙醇含量为(47.05±1.71)%。结论顶空气相色谱方法准确、灵敏、重复性好,可用于碘酊中乙醇含量测定;不确定度评定有利于提高测定结果的准确性。

Objective To establish an auto headspace-gas chromatography（HS-GC）method for determination of ethanol in iodine tincture,and to evaluate the uncertainty.Methods The HS-GC internal standard curve method was adopted for determination of ethanol with Thermo TG-WAXMS（30.0 m×0.25 mm,0.5μm）,FID and propanol as the internal standard.The sources of uncertainty during measurement were analyzed,and a mathematical model was established to calculate the combined standard uncertainty and the expanded uncertainty.Results Ethanol showed good linear relationships in the range of 0.1251.50 ml·L-1.The average recovery was 100.07%,and RSD was 1.53%.The expanded uncertainty was1.71%（k=2）.The content of ethanol was（47.05±1.71）%.Conclusion This method is accurate,sensitive and has good repeatability for quality control of ethanol in iodine tincture.This mathematic model of uncertainty is applicable to evaluation of accuracy,it makes the measurement result more accurate.