Uncertainty evaluation of total arsenic in pork by inductively coupled plasma mass spectrometry

ObjectiveTo make uncertainty evaluation of total arsenic in pork by using the national food safety standard "GB 5009.11-2014 determination of total arsenic and inorganic arsenic in food", and discuss the influence of each uncertainty component on the determination results so as to improve the accuracy of the experimental results.

MethodsThe uncertainty sources that affected the measurement results in the measurement process, including repeatability measurement, sample weighing, sample dilution, standard concentration, standard curve and so on were evaluated.The uncertainty introduced by the repeatability measurement was evaluated by class A, the uncertainty caused by other factors was evaluated by class B, and the phase was calculated according to each component.The synthetic standard uncertainty and the relative expanded uncertainty were discussed, and so were the influence of the uncertainty components on the measurement results.

ResultsAccording to the contribution of uncertainty from large to small was the sample standard concentration, standard curve, repeatability determination, sample weighing and sample dilution.The calculated relative composite standard uncertainty was 0.0405, and the relative expanded uncertainty was 0.081 (k=2).

ConclusionThe experimental results show that the concentration of standard substance has a great influence on the measurement process, so it is necessary to standardize the dilution process and simplify the dilution procedure to improve the accuracy of measurement results.