高效液相色谱法测定卤牛肉中苯甲酸含量的不确定度评估

Evaluation of Uncertainty in Determination of Benzoic Acid in Braised Beef by HPLC

本实验采用高效液相色谱法(High Performance Liquid Chromatography,HPLC)测定卤牛肉中苯甲酸的含量,并进行不确定度评估,结合数学模型与实验全过程,确认苯甲酸标准系列溶液配制、样品处理、标准曲线拟合、仪器测定4个过程为不确定度的主要来源,通过分析、计算,得到苯甲酸的含量为0.215 4 g·kg^(-1),其扩展不确定度为0.018 5 g·kg^(-1),苯甲酸含量可以表示为(0.215 4±0.018 5)g·kg^(-1)(k=2,置信区间95%)。此外,对上述4个过程的不确定度进行比较,发现标准曲线拟合过程引入的不确定度是总不确定度的主要来源,系列标准曲线配制过程和仪器测定对不确定度的影响相当,样品制备过程的影响较小。本实验为此类食品苯甲酸含量测定的不确定度评估提供依据。

This experiment used high performance liquid chromatography(HPLC)to determine the content of benzoic acid in braised beef,and evaluated the uncertainty.Combining mathematical models and the entire experimental process,it was confirmed that the preparation of benzoic acid standard series solution,sample processing,standard curve fitting,and instrument measurement were the main sources of uncertainty.Through analysis and calculation,the content of benzoic acid was 0.2154 g·kg^(-1),Its expanded uncertainty is 0.0185 g·kg^(-1),and the benzoic acid content can be expressed as(0.2154±0.0185)g·kg^(-1)(k=2,confidence interval 95%).In addition,comparing the uncertainty of the four processes mentioned above,it was found that the uncertainty introduced by the standard curve fitting process is the main source of total uncertainty.The influence of the series standard curve preparation process and the instrument measurement process on uncertainty is similar,while the influence of the sample preparation process is relatively small.This experiment provides a basis for evaluating the uncertainty of the determination of benzoic acid content in such foods.