硝酸银标准溶液定值分析

Certifying Analysis of AgNO_3 Standard Solution

标准溶液定值过程中,标准物质的等级和质量是确保标准溶液化学计量准确的关键。实验中应用有证二级标准物质级与工作基准物质级氯化钠对硝酸银标准溶液进行定值。结果表明,硝酸银标准溶液的质量分数分别为:ωAgNO3(二级标准级)=(1.7375±0.0198)%;k=2;ωAgNO3(工作级)=(1.7143±0.0460)%;k=2。二级有证标准物质的溯源性高于工作基准物质,二级标准物质的测量不确定度小于工作基准试剂,保证了后续测量量值的准确性。

The grade and quality of standard material is important in the course of certifying standard solution. In this paper, reference material NaCl with two different grades has been used to certify AgNO3 solution. The mass concentration of AgNO3 solution ωAgNO3 are（1. 7375±0. 0198）%（k=2）and （1. 7143±0. 0460）%（k=2） respectively when measured by certified and secondary reference material. Uncertainty of certified reference material is smaller than secondary reference material. So it is better to use certified reference material when permitted.