气相色谱质谱法快速测定谷物中敌草快含量的优化及其不确定度评定
目的 优化气相色谱质谱法快速测定谷物中敌草快的分析方法, 并评定测定小麦敌草快含量的不确定度。方法 样品经二氯甲烷净化, 超纯水萃取, 硼氢化钠溶液衍生, 正己烷萃取上机, 气相色谱质谱法测定, 外标法定量。以大米、小麦、玉米为样品, 测定加标回收率证实方法的可行性。以测定小麦敌草快数据为基础, 依据JJF 1135-2005《化学分析测量不确定度评定》和JJF 1059.1-2012《测量不确定度评定与表示》, 考察标准溶液配制、标准曲线拟合、样品称量、定容体积、仪器重复测量和回收率等主要因素引入的不确定度, 并对不确定度的各分量进行计算和合成。结果 3种谷物加标回收实验, 均满足实验要求。当小麦中敌草快含量为0.094 mg/kg时, 在95%的置信区间下, 其扩展不确定度为0.013 mg/kg(k=2)。实验过程中的不确定度主要来源于标准溶液配制、标准曲线拟合。结论 此法提高固液萃取、液液萃取效率, 且操作简单。并可通过选择精度高的移液、定容器皿, 规范操作有效减少不确定度, 保证测量结果的准确性。
Objective To optimize the method for rapid determination of diquat in cereals by gas chromatography-mass spectrometry (GC-MS), and evaluate the uncertainty in determination of diquat in wheat by GC-MS. Methods The sample was purified by dichloromethane, extracted with deionized water, and derived by sodium borohydride solution. The extraction liquid were extracted by hexane and determined by GC-MS. The target object was quantified with external standard curve. Rice flour, wheat flour and corn flour were selected as samples to prove the feasibility of the method. According to JJF 1135-2005 Evaluation of uncertainty in chemical analysis measurement and JJF 1059.1-2012 Evaluation and expression of uncertainty in measurement, the factors affecting the determination results of diquat in wheat were investigated, such as standard curve, measurement repeatability, weighing, constant volume and recovery rate, and the uncertainty components were calculated and synthesized. Results Recovery experiments of 3 kinds of grain met the experimental requirements. When the determination result of diquat in wheat was 0.094 mg/kg, the expand uncertainty was 0.013 mg/kg (k=2) under the confidence interval of 95%. The results showed that the main sources of uncertainty in the determination were standard solution preparation and the standard curve. Conclusion This method improves the efficiency of solid-liquid extraction and liquid-liquid extraction, which is simple to operate. By selecting high-precision pipetting and fixed containers, the specification operation can effectively reduce the uncertainty and ensure the accuracy of the measurement results.
标题：气相色谱质谱法快速测定谷物中敌草快含量的优化及其不确定度评定
英文标题：Optimization for rapid determination of diquat in cereals by gas chromatography-mass spectrometry and uncertainty evaluation of the determination of diquat
作者：
张森 中粮营养健康研究院营养健康与食品安全北京市重点实验室
时超 中粮营养健康研究院营养健康与食品安全北京市重点实验室
张瑞刚 中粮营养健康研究院营养健康与食品安全北京市重点实验室
杨永坛 中粮营养健康研究院营养健康与食品安全北京市重点实验室
中文关键词:不确定度,敌草快,气相色谱质谱法,谷物,
英文关键词:uncertainty,diquat,gas chromatography mass spectrometry,wheat,
发表日期：2019-01-16
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