Top-down法评定EDTA络合滴定法测定海洋沉积物中碳酸钙含量的不确定度  

Evaluation of uncertainty for the determination of calcium carbonate in marine sediments by EDTA complexometric titration based on Top-down method

作　　者：李强[1] 杨天邦 黄雪华[1] 雷知生[1] 贺晓宇 陈宋英 LI Qiang;YANG Tianbang;HUANG Xuehua;LEI Zhisheng;HE Xiaoyu;CHEN Songying(Guangzhou Marine Geological Survey,National Engineering Research Center of Gas Hydrate Exploration and Development,Guangzhou 511458,China)

机构地区：[1]广州海洋地质调查局,天然气水合物勘查开发国家工程研究中心,广州511458

出　　处：《化学分析计量》2024年第1期112-117,共6页Chemical Analysis And Meterage

基　　金：南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0506)。

摘　　要：依据Top-down技术中的质控图法对EDTA络合滴定法测定海洋沉积物中碳酸钙含量的不确定度进行评定。利用2021年质控样标准物质GBW 07333、GBW 07314和GBW 07316中CaCO_(3)测定值的时序数据进行评定,3组时序数据正态统计量A^(2*)(s)和独立性统计量A^(2*)(RM)均小于1,CaCO_(3)测定值、A_(EWMi)和移动极差控制图没有失控点,3组时序数据处于受控状态。当CaCO_(3)质量分数分别为2.05%、6.20%和38.56%时,计算得其扩展不确定度分别为0.08%、0.07%和0.20%。将测量不确定度与对应含量值进行线性拟合建立了不确定度预测模型,GBW 07309和GBW 07334中CaCO_(3)的测量不确定度预测值分别为0.09%和0.18%,预测值与Top-down技术获取的评定结果较为吻合。The quality assurance and control charting method based on Top-down technique was described,which was used to evaluate uncertainty for the determination of CaCO_(3)in marine sediments by EDTA complexometric titration.The quality control data,accumulated in routine analysis of CaCO_(3)in national certified reference materials GBW 07333,GBW 07314 and GBW 07316 in 2021,was used to evaluate uncertainty.The statistics of normal distribution A^(2*)(s)and independence A^(2*)(RM)for three data sets were less than 1.There was no out-of-control points in the CaCO_(3)measurement value,A_(EWMi)and moving range control chart,which indicated that the three data sets were under a controlled state,consequently,the result of the expanded uncertainty was 0.08%,0.07%and 0.20%when the mass fraction of CaCO_(3)was 2.05%,6.20%and 38.56%,respectively.The prediction model of the uncertainty for the determination of CaCO_(3)was established by using linear regression analysis,and the predicted value of the measurement uncertainty for the determination of CaCO_(3)in GBW 07309 and GBW 07334 was 0.09%and 0.18%,respectively.The predicted values were in good agreement with the evaluation results obtained by the Top-down technique.

关 键 词：海洋沉积物 碳酸钙 不确定度评定 质控图法 络合滴定法 

分 类 号：O655.25[理学—分析化学]