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水中重金属元素含量一般很低,用火焰原子吸收法无法直接测出其含量,必须采用一些前处理方法,富集才能测出,多数采用MIBK萃取或巯基棉富集,操作复杂,使用有毒有机试剂。我们根据Mg(OH)_2胶状沉淀能同时共沉一些重金属元素,在梨形分液漏斗内产生共沉淀,然后将沉淀从漏斗下部分离出来,很容易达到富集目的。采用分液漏斗比虹吸或过滤要方便得多,分离完全,浓缩倍数高。经多次试验,方法变异系数为3.03%～6.37%,回收率为89%～103%,检出限可达到 Cd 3·5ng·ml_(-1),Pb 16.7ng·ml_(-1),Cu 5ng·ml_(-1)。 1 试验部分1·1 仪器与试剂 GFU-202型原子吸收光谱仪镉、铅、铜空心阴极灯
The content of heavy metals in water is generally very low. Flame atomic absorption spectrometry can not directly measure the content of heavy metal elements. Some pre-treatment methods must be used to determine the enrichment. Most of them are enriched by MIBK extraction or sulfhydryl cotton. The operation is complicated and toxic organic reagents . According to Mg (OH) _2 colloidal precipitation, we can co-sink some heavy metal elements in the pear-shaped separatory funnel to produce coprecipitation, and then the precipitate separated from the bottom of the funnel, it is easy to enrich the purpose. Separation funnel than using siphon or filtration to be much more convenient, fully separated, high concentration ratio. After repeated experiments, the coefficient of variation (CV) was 3.03% ~ 6.37% and the recovery rate was 89% ~ 103%. The detection limits were as follows: Cd 3 · 5ng · ml -1, Pb 16.7ng · ml -1, Cu 5 ng · ml _ (-1). 1 Experimental Section 1.1 Instruments and Reagents GFU-202 atomic absorption spectrometry cadmium, lead, copper hollow cathode lamp