析相微萃取-石墨炉原子吸收法测定地质样品中痕量金

Determination of trace aurum in geological samples by microsphere phase separation extraction-graphite furnace atomic absorption spectrometry(GF-AAS)

以MIBK为络合剂和提取剂,乙醇为助溶剂,建立了析相微萃取-石墨炉原子吸收法测定地质样品中痕量金的分析方法。详细探讨了金的不同析相微萃取体系的特性及析相规律,优化了金-MIBK体系的最佳析相微萃取条件及石墨炉升温程序。所建立的方法线性范围为0.006-1.0μg/L,检出限为0.0013μg/L,相对标准偏差为1.5%（n=11）,用于国家地质标准参考物质（GBW07289）的测定,分析结果与推荐值吻合。

A method for the determination of Au（ Ⅲ ） with microsphere phase separation extraction by graphite furnace atomic absorption spectrometry （GF-AAS） in geological samples was developed. The complex of Au（ Ⅲ ） and Methyl isobutyl ketone （4-Methyl-2-pentanone） （MIBK） was extracted to organic phase, then the analyte was separated out of solution as microsphere by adding the water into the solution for changing the ratio of water to organic phases. The characteristic of microsphere phase separation was investigated and the experimental conditions were optimized. The linear concentration range of the method was from 0.006 to 1.0 μg/L, and the detection limit was 0.0013 μg/L. The precision （RSD） was 1.5 % （11 replicate determinations, 0.5μg/L）. The proposed method was applied to the determination of Au（ Ⅲ ） in geological reference samples （GBW07289）, and the analytical results are in agreement with the recommended values.