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评价了火焰原子吸收光谱法测定聚乙烯包装材料中重金属(以Pb计,下同)的不确定度,对食品包装材料的安全性评估提供理论支撑。实际检测数据通过了正态性验证,并在符合正态分布的前提下进行了质控分析,分别建立了单值(I)控制图、移动极差值(MR)控制图,结果显示测量系统的变异仅受随机误差影响,且有99.7%的正态分布数据落入控制限内,进一步验证了数据的正态性分布。绘制了指数加权移动平均值(EWMA)控制图,显示所测结果并未出现超限数据,且集中在中心线附近,说明测试结果具有较好的集中性。最终,在确信火焰原子吸收光谱法(FAAS)测定重金属的系统具有可信性和其偏倚可忽略不计的情况下,给出测试样本的评估参考量值为0.014mg/L,并通过显著性t检验证明了方法测定过程中不存在系统误差。
The flame atomic absorption spectrometry (FAAS) was used to evaluate the uncertainty of the determination of heavy metals (Pb) in polyethylene packaging materials and provide theoretical support for the safety assessment of food packaging materials. The actual test data passed the normality verification, and the quality control analysis was carried out on the premise of the normal distribution. The single value (I) control chart and the moving limit (MR) control chart were established respectively. The results showed that the measurement system Of the variance was only affected by random error, and 99.7% of the normal distribution data fell within the control limits, further verifying the normal distribution of the data. An EWMA control chart was plotted, showing that the measured data did not show any over-limit data and were concentrated near the centerline, indicating that the test results have better concentration. Finally, given the confidence and bias that Flame Atomic Absorption Spectrometry (FAAS) is a reliable system for the determination of heavy metals, the estimated reference value for the test sample is given as 0.014 mg / L, The test proves that there is no systematic error in the method determination.