卡尔·费休库仑滴定法测定高纯乳酸中水分

Determination of water in high purity lactic acid with Karl Fischer coulometric titration

针对乳酸易吸湿的物理特性,在含水量较低的手套箱实验环境下采用卡尔·费休库仑法水分测定仪,对高纯乳酸中水分含量进行研究。结果表明,在手套箱环境下,乳酸取样量为0.10 g,搅拌速度500 r/min,萃取时间60 s,相对停止漂移值为5μg/min时,方法测定结果的相对标准偏差为3.8%(n=10)。采用国家一级水分标准物质对该方法进行了验证,测定值在该标准物质的不确定度范围内。

In glove box experiment environment,the determination method of water content in high purity lactic acid was studied by using Karl Fischer coulometric titrator,considering the physical properties of the lactic acid easy to moisture absorption.The results showed that the relative standard deviation of the method was 3.8%(n=10)under the conditions of in the glove box,0.10 g of lactic acid sampling volume,500 r/min of stirring speed,60 s of extraction time,and 5μg/min of relative stop drift value.The method was verified by using the national water content reference material,and the results were stable within the range of uncertainty.