[Objective] To establish an evaluation method for uncertainty in spectrophotometry determination of nitrite in fruit. [Method] The source of uncertainty in the spectrophotometry determination of nitrite in apple were investigated by analyzing the whole determination procedure, each uncertainty component was modeled, synthesized and expanded to develop a method for the evaluation of uncertainty in spectrophotometry determination of nitrite in apple. [ Result ] The main uncertainties which affect the result include: measurement repeatability, nitrite mass determined by standard curve, sample dilution and sample weighting. The uncertainty report was that the nitrite content in apple was determined to be (70.72 ?.07) mg/kg,A =2. [Conclusion] The study can provide scientific basis and theoretical support for accuracy determination nitrite in fruit.%[目的]建立分光光度法测定水果中硝酸盐的不确定度评定方法.[方法]通过对分光光度法测定苹果中硝酸盐含量的过程的研究,确定了测定结果的不确定度,建立了不确定度的数学模型,对各不确定度分量进行了合成和扩展,最终建立了苹果中硝酸盐含量的不确定度评定方法.[结果]影响苹果中硝酸盐含量测量结果的不确定因素主要包括:称量不确定度、体积不确定度、曲线拟合不确定度、测量重复性引起的不确定度.苹果中硝酸盐含量不确定度报告为:(70.72±7.07) mg/kg,包含因子k=2.[结论]研究可为准确测定水果中硝酸盐含量提供科学依据和理论支撑.
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