2,4-二氯苯氧乙酸纯度标准物质定值方法及不确定度评估

Purity Determination and Uncertainty Assessment of Certified Reference Material of 2,4-Dichlorophenoxyacetic Acid

研制2,4-二氯苯氧乙酸纯度标准物质。采用质量平衡法和氢谱定量核磁法对2,4-二氯苯氧乙酸纯度标准物质候选物进行纯度定值,对主组分影响较大的水分含量采用卡尔费休法准确测量。对2,4-二氯苯氧乙酸纯度标准物质进行了均匀性检验、稳定性考察以及不确定度评估。2,4-二氯苯氧乙酸纯度标准物质的纯度值为99.6%,扩展不确定度为0.2%(k=2),水分含量为0.291%,特性量值均匀性良好,12个月内稳定性可靠。2,4-二氯苯氧乙酸纯度标准物质符合国家有证标准物质条件并获得国家一级标准物质认定,编号为GBW09291。

This study aims to develop purity reference material of 2,4-dichlorophenoxyacetic acid.Purity rating of 2,4-dichlorophenoxyacetic acid purity reference standard candidate was performed by mass balance method and ^(1)HNMR-based quantitative method,while the moisture content that has a large impact on the main component was accurately measured by Karl Fischer method.The purity reference standard 2,4-dichlorophenoxyacetic acid was subjected to homogeneity study,stability studies,and uncertainty assessments.The purity value of the 2,4-dichlorophenoxyacetic acid standard material was 99.6%,the expansion uncertainty was 0.2%(k=2),the moisture content was 0.291%,the characteristic value was uniform,and the stability was reliable within 12 months.The purity standard 2,4-dichlorophenoxyacetic acid met the conditions of the national certified standard substance and had been recognized as a national first-class standard substance,numbered GBW09291.