牛肝标准物质中氯含量的定值方法研究

针对基体标准物质中氯含量的准确定值问题,采用高温燃烧水解-离子色谱法和干灰化-电位滴定法对牛肝标准物质中的氯含量进行了测定。对两种方法的前处理和测定条件进行了优化,实验结果表明两种方法的测定结果一致,测定结果的相对标准偏差分别为0.7%和1.1%。采用NIST牛肝标准物质(SRM1577c)对两种方法进行了验证,两种方法的测定结果与标准值相符。对两种方法测定结果的不确定度进行了评定,氯测定结果的相对扩展不确定度(k=2)分别为1.6%和2.2%。两种方法测定牛肝中氯含量都准确可靠,能够满足标准物质定值的要求。

Determination of Chlorine in Bovine Liver Reference Material

The determination of chlorine in matrix reference material is difficult. The content of chlorine in reference material of bovine liver was determined by ion chromatography combined with pyrohydrolysis and potentiometric titration following dry ashing digestion. The pretreatment and determination conditions of the two methods were optimized, the experimental results show that the results of the two methods are consistent,the relative standard deviations of the measurement results are 0.7% and 1.1% respectively. The two methods were verified by using NIST bovine liver reference material (SRM1577c), the results of the two methods are consistent with the standard values. The uncertainties of the determination results of the two methods were evaluated, and the relative expanded uncertainties of the chlorine determination results (k=2) are 1.6% and 2.2% respectively. Both methods used to determine the chlorine content in bovine liver are accurate and reliable, and can meet the requirements of reference material certification.