Evaluation of Uncertainty in Determination of Lead in Milk and Dairy Products by Atomic Absorption Spectrometry

Abstract

In the field of food safety inspection, researchers should fully consider the impact of measurement uncertainty to ensure the accuracy of the results, Especially when it affects the determination of detection results.This study is to establish the mathematical model of uncertainty, Synthesize and expand each uncertainty component .Finally, the uncertainty evaluation method for the determination of lead in milk and dairy products by atomic absorption spectrometry was established. Take milk powder as an example, the uncertainty of graphite furnace atomic absorption spectrometry method 1 in GB 5009.12-2017 National Food Aafety Standard Determination of Lead in Foods was evaluated by referring to JJF 1059.1-2012 Evaluation and Expression of Measurement Uncertainty. When the standard result of lead content in milk was 0.095 mg/kg, the synthetic standard uncertainty of the determination result was 0.0022 mg/kg, k=2, and the extended uncertainty was 0.005 mg/kg, and the result could be expressed as (0.095±0.005) mg/kg. The uncertainty of measurement results is mainly due to the uncertainty component introduced by test repeatability and standard solution concentration. Therefore, in the actual testing work, the accuracy and reliability of the results can be ensured by increasing the number of standard working fluid, using glass instruments with higher accuracy, and increasing the number of parallel samples.