干灰化–离子色谱法测定木耳标准物质中的钾、钙、镁

采用离子色谱法对木耳标准物质中的K,Ca,Mg进行测定,对样品消解以及离子色谱分离条件进行了优化。在优化实验条件下,该法对木耳中K,Ca,Mg 3种元素测定结果的相对标准偏差小于1.0%(n=7)。采用该方法对NIST西红柿叶标准物质(SRM1573a)进行测定,测定结果与标准值相符,同时与ICP–OES方法比较验证,两者测定结果一致。对该方法测定结果的不确定度进行了评定,K,Ca,Mg测定结果的相对扩展不确定度(k=2)分别为2.3%,3.3%,1.9%。该方法准确可靠,能够满足标准物质定值的要求。

Determination of K,Ca and Mg in Black Fungus Certiifed Reference Material by Dry Ashing-ion Chromatography

The contents of potassium,calcium and magnesium in black fungus certified reference material were determined by ion chromatography after dry ashing digestion. Sample digestion and ion chromatography conditions were optimized. Under optimal conditions, the relative standard deviation of detection results of K,Ca and Mg in black fungus was less than 1.0%（n=7）. The method was used to determine tomato leaves reference material （NIST SRM1573a）, and the results were consistent with standard value. The results detected by the method were compared with those detected by ICP–OES, and they were coincided with each other. The relative expanded uncertainties （k=2） of the results were evaluated, which were 2.3%,3.3%and 1.9%for K,Ca and Mg,respectively. The method is accurate and reliable,and it can meet the requirements of certification of reference material.