称重法配制标准溶液研究及其不确定度评估

在标准溶液配制及稀释的过程中放弃了传统的定量移液管,采用精密电子天平作为定量工具。精密电子天平准确度高,重复性好,不需考虑溶液黏度、管口流速等因素对不确定度的影响,而且明显地降低了在标准溶液逐级稀释过程中由于读数、操作等原因产生的误差,可实现大比例稀释,操作简便。根据《化学分析中不确定度的评估指南》(CNAL/AG07:2002)评定了此方法与传统溶液配制方法的不确定度。利用电感耦合等离子体原子发射光谱法(ICP-AES)验证了其准确性和线性,均获得满意结果。本法适用于ICP-AES法测定样品中的主元素(含量在x%~xx%)时的标准溶液配制,也可应用于原子荧光光谱、原子吸收光谱等仪器系列标准溶液的配制。

Study on Standard Solution Preparation with Weighting Method and Its Uncertainty Evaluation

A new method for standard solution preparation was introduced, which utilized the sophisticated electronic balance as a quantitative tool in place of traditional quantitative tubes in standard solution preparation and dilution. Both the accuracy and repeatability by new method are good and without considering the influence factors, such as solution viscosity, on uncertainty. And the new method also greatly reduced the errors from scale reading and dilution operation etc. in gradual dilution of standard solutions. Based on Guide to Uncertainty Evaluation in Chemistry Analysis (CNAL/AG07:2002), the uncertainties from the new and traditional methods were evaluated. The accuracy and linearity of the new method were also tested by ICP-AES determination of analytes with satisfactory results. The method is suitable for the preparation of calibration solutions in determination of the major components with concentration range ofx%~xx% by ICP-AES and preparation of calibration solutions in AFS and AAS analysis.