气相色谱法测定菜粕异硫氰酸酯不确定度评定

对采用气相色谱内标法测定菜粕中的异硫氰酸酯含量的测量不确定度进行了评定。建立测量模型,分析确定菜粕中异硫氰酸酯含量的不确定度来源,并对测量过程中的不确定度分量进行逐层分析与合成,当菜粕的丙烯基异硫氰酸酯含量为99.2 mg/kg时,得到其合成标准不确定度和扩展不确定度分别为2.2、4.4 mg/kg。结果表明,校正因子测定引入的不确定度分量对合成标准不确定度的贡献最大,样品重复测定、回收试验和添加内标溶液带来的不确定度分量也不容忽视,试样称量对总不确定度的贡献最小,为采用该方法测定菜籽饼粕中异硫氰酸酯含量的质量控制提供了理论依据。

Uncertainty Evaluation of Determination of allyl isothiocyanate in rapeseed meal with Gas Chromatography by Using Internal Standard Method

In this paper, the measurement uncertainty for determination of allyl isothiocyanate in rapeseed meal with gas chromatography by using internal standard method was evaluated. The measurement model of each component in the process of measurement was established. The main sources of uncertainty were analyzed and identified. The impact of every uncertainty component for the measurement uncertainty was estimated. Based on the quantitative analysis of every source, the the relative standard uncertainty of measurement result was obtained. The determination result of allyl isothiocyanate content in rapeseed meal was 99.2 mg/kg, the combined standard measurement uncertainty and expanded measurement uncertainty were 2.2 mg/kg and 4.4 mg/kg respectively. The evaluation indicated that correction factor made the most contribution to the combined relative standard measurement uncertainty. The influence of repetitive test,the spike recovery and internal standard solution could not be neglected. TheSeffectSof sample weightSwasSminimal. This evaluation provided a theoretical basis for the quality control of allyl isothiocyanate content determination in rapeseed meal.