熔封过程对挥发性有机物溶液标准物质的量值影响研究

Study on the influence of melt sealing process to the value of volatile organic solution reference materials

本文研究了挥发性有机物溶液标准物质在熔封过程中影响量值稳定的主要因素以及对定值结果的不确定度贡献。通过实验考察溶质沸点在-13.4℃至220℃的7种挥发性有机物溶液标准物质在不同条件下熔封,使用外标法准确测定熔封前后溶液的量值变化。研究结果表明,以甲醇为溶剂,溶质沸点在-13.4℃至80℃范围内的挥发性有机物溶液的最佳冷却温度为-20℃,溶质沸点在80℃至220℃范围内溶液的冷却温度相对较高。溶质沸点越低,对挥发性有机物溶液的分液方式要求越高,全密闭管路的分液方式最佳。在安瓿瓶熔封过程中使用冷却套管,可以有效的减少火焰热效应对溶液的影响。对实验考察的7种挥发性有机物溶液标准物质的不确定度可降低至1%以内。

The purpose is to discuss the factors that afect the stability of the value and the contribution of uncertainty in the meling process of volatile organic solution reference materials.Seven volatile organie solutions with solute boiling points between-13.4℃and 220℃were investigated through experiments.They were sealed under different conditions,and quantitative changes in the vol-ume of the sealed solutions were determined by exteral standard method.The results show that the optimal cooling temperature of volatile organic solution with methanol as solvent and solute boiling point within the range of-13.4℃to80℃is-20℃,and the cooling temperature of solution with solute boiling point within the range of 80℃to 220℃is relatively higher.The lower the boil-ing point of solute,the higher the requirement for the separation method of volatile organie solution.The best separation method is the fully closed pipeline.The use of cooling sleeve in the process of ampoule sealing can flectively reduce the influence of flame thermal effect on the solution.The uncertainty of reference materials for seven volatile organic solutions investigated in the experi-ment can be reduced to less than 1%.