分析痕量元素时水样的的保存

PRESERVATION OF WATER SAMPLES FOR TRACE ELEMENT ANALYSIS

本文评述了天然水样品中PPb级的Cu、Pb、Zn、Cd、Cr^(3+)、Cr^(6+)、Ni、Co、Mn、Fe、As^(3+)、As^(5+)、Se^(4+)、Se^(6+)、Hg、F-的保存条件。如水样的pH值,金属离子的初始浓度,容器的材料,保存的时间和温度等等。建议水样经0.45微米泸膜过泸后。用硝酸酸化至pH≤1.5(As、Se用硫酸酸化),对于Hg不仅酸化,还应加入半胱氨酸、氯金酸或重铬酸钾等保护剂。水样贮存在干净的高密度聚乙烯或聚四氟乙烯(特氟隆)容器中,在4℃的条件下为最佳。

A review is presented on the preservation conditions, such as pH of water solution, the initial concentrations of metals, type of container materials, storage time and temperature, feor determination of Cu, Pb, Zn, Cd, Cr, Ni, Co, Mn, Fe, As, Se, Hg and F at ppb levels in water samples. It is recommended to store water samples in a clean high-pressured polyethylene, or polytetrafluoroethylene container at 4℃ and acidify with nitric acid to pH≤1.5 (with sulphuric acid for Se and As). Complex forming agents or oxidants should be added for Hg. 38 references are cited.