称量法配制金属元素标准曲线

Weighing method for preparing standard curve of metal elements

目的建立称量法配制金属元素标准曲线的方法。方法利用万分之一分析天平和移液器,通过"衡量法",质量与实际体积计算测定标准溶液的密度。移取1 ml标准溶液于洁净塑料瓶中,记录其准确质量换算实际体积,按比例加入超纯水,使金属元素标准溶液介质的酸浓度稀释至1%,再加入1%的硝酸溶液至100 g,记录准确质量,按1%硝酸的密度计算稀释后体积,换算稀释后标液浓度,按照实际需求,配制相应的标准曲线浓度。标准系列的配制使用洁净塑料瓶,按质量比值稀释,计算实际浓度,完成配制过程。结果标准曲线相关系数r=1.000 0,环境水样质控检测结果准确,方法比对结果一致,称量法的不确定度与容量法的不确定度保持一致。结论本方法准确可靠、简便快捷、能够有效避免污染,适用于金属元素标准曲线的配制。

Objective To establish a method for preparing the standard curve of metal element by weighing method. Methods The density of the standard solution was calculated by using a 1/10 000 analytical balance and a pipette to determine the mass and actual volume. 1 ml standard solution was piped into a clean plastic bottle and the exact volume was noted for converting the actual volume. The ultrapure water was added proportionally to dilute the acid concentration of the metal standard solution into1%. Then 1% nitric acid solution was added up to 100 g and the accurate quality was recorded,finally the diluted volume was calculated according to the density of 1% nitric acid. The corresponding standard curve is prepared according to the actual demanding after contrasting the diluted standard concentration. Results The correlation coefficient was 1. 000 0,the results of environmental water quality controlling sample were accurate. The results of two methods were consistent. The uncertainty of the weighing method is consistent with the uncertainty of the volumetric method. Conclusion This method is accurate,simple and convenient,which can avoid pollution and is suitable for the preparing standard curve of metal elements.