石墨炉原子吸收光谱法(GFAAS)测定条斑紫菜中铅的不确定度分析

Uncertainty analysis of lead in Porphyra yezoensis by GFAAS

依据GB 5009.12—2010《食品安全国家标准食品中的铅的测定》方法对条斑紫菜一次加工菜中的铅进行测定,并按照JJF 1059.1—2012《测量不确定度评定与表示》的要求对测定结果进行不确定度评定。结果表明:测定时铅标准溶液配制和样品称量是引起测量不确定度的主要因素,计算得出合成不确定度和最终的扩展不确定度分别为6.15×10^(-2)和1.23×10^(-1)。本试验中铅含量为0.44 mg/kg时,测量结果的扩展不确定度为0.054(k=2),该方法适用于条班紫菜中铅含量测定的不确定度评定。

According to GB 5009.12—2010,the lead content in Porphyra yezoensis was determined by a-tomic absorption spectrophotometry,and the uncertainty of the determination result was evaluated on the require-ment of JJF 1059.1—2012.The results showed that the major sources of the uncertainty were the lead standard curve fitting and the weighing of samples.The combined uncertainty and expanded uncertainty were obtained,and the results were 6.15 ×10 -2 and 1.23 ×10 -1 ,respectively.While the lead content in detected sample was 0.44 mg/kg,the extend uncertainty of the determination result was 0.054 mg/kg（k =2）.The method was suit-able for evaluating the uncertainty of lead in Porphyra yezoensis.