微波消解火焰原子吸收法测定火龙果中铁的不确定度评定

Evaluation of Uncertainty in Determination of Iron in Pitaya Fruit by Microwave Digestion-Flame Atomic Absorption Spectrometry

对微波消解火焰原子吸收法测定火龙果中铁含量的不确定度进行评估.建立相应的不确定度数学模型,根据测试过程分析不确定度来源有7个方面,计算各不确定度分量,得到火龙果中铁含量测定结果是X=(1.308±0.281)mg/100 g(k=2).测量过程不确定度的主要来源是样品溶液测量、样品空白及样品溶液定容等3个方面,其中,标准曲线制作和工作曲线拟合引起的不确定度最大.不确定度评定结果可为水果等营养元素检测方面提供参考,避免或减少一些不必要检测误差,使测试结果更加准确.

The uncertainty of the determination of iron in pitaya fruit was evaluated by the microwave digestion-flame atomic absorption spectrometry.The corresponding uncertainty mathematical model was established.According to the analysis of uncertainty sources in the test process,there were 7 aspects.The uncertainty components were calculated.The result of the determination of iron content in Pitaya was X=(1.308±0.281)mg/100 g(k=2).It was found that the main sources of uncertainty in the measurement process were the measurement of sample solution,the blank of sample and the constant volume of sample solution.Among them,the uncertainty caused by standard curve making and working curve fitting was the largest.Uncertainty assessment results can provide references for the detection of nutrients,avoid or reduce some unnecessary detection errors,and make the test results more accurate.