石墨炉原子吸收光谱法测定鲜虾中镉含量的不确定度评定

Uncertainty evaluation for the determination of cadmium in fresh shrimp by graphite furnace atomic absorption spectroscopy

中文关键词:  石墨炉原子吸收光谱法  鲜虾  镉  不确定度

英文关键词:graphite furnace atomic absorption spectroscopy  fresh shrimp  cadmium  uncertainty

中文摘要:

      目的 评定石墨炉原子吸收光谱法测定鲜虾中镉的不确定度。方法 样品经微波消解后稀释, 将样品消解液注入原子吸收分光光度计的石墨炉原子化器中。采用标准曲线法定量。分析测定过程中的不确定度来源, 对不确定度的组成进行了评定和量化。根据数学模型计算了样品中镉的含量, 得到合成标准不确定度和扩展不确定度。结果 石墨炉原子吸收光谱法测定鲜虾中镉含量为1.6 mg/kg, 扩展不确定度为0.2 mg/kg (k=2), 结果表达为(1.6±0.2) mg/kg, k=2。结论 不确定度的主要来源是样品溶液中镉浓度的测定, 其次是重复测定和加标回收实验, 其他因素引起的不确定度可以忽略。

英文摘要:

      Objective To evaluate the uncertainty for the determination of cadmium in fresh shrimp by graphite furnace atomic absorption spectroscopy (GFAAS). Methods After microwave digestion, the sample was diluted and injected into a graphite furnace with atomic absorption spectrophotometer. Cadmium content was determined by standard curve method quantitative. The sources of uncertainty in the process of measurement were analyzed, and the components of uncertainty were evaluated and quantified. The synthetic standard uncertainty and extended uncertainty were calculated according to the mathematical model. Results The content of cadmium in the sample was 1.6 mg/kg by GFAAS. The expanded uncertainty was 0.2 mg/kg (k=2), and the result was expressed as (1.6±0.2) mg/kg (k=2). Conclusion The determination of cadmium concentration in the sample solution is the main source of uncertainty, followed by the repeated determination and standard recovery of the sample, and the uncertainty caused by other factors can be ignored.