石墨炉原子吸收法测定地质样品中痕量银

Trace silver determination by graphite furnace atomic absorption

目前地质样品中的痕量银一般采用双电极发射光谱法进行测定,但方法流程长、人力物力消耗大、数据稳定性差,且很难满足银检出限的要求。为了解决这些问题,该文以硝酸-高氯酸-氢氟酸溶解试样,2%的盐酸浸取,2%的磷酸氢二铵-2%硫脲溶液作为基体改进剂,以石墨炉原子吸收法测定地质样品中痕量银;采用该方法对国家一级标准物质及实际样品进行了分析,获得了令人满意的结果;方法的检出限为0.02μg/g,加入标准物质回收率为95.0%~98.3%,相对标准偏差为4.56%~9.98%。该试液体系可应用于其他元素测定,无需再溶解样品,简化了分析流程,降低了测试成本。该方法简便、快速、准确。

Dual electrodes emission spectroscopy commonly used in the determination of trace silver in geological samples is lengthy in flowsheet and consumes much man power and lots of material resources besides its poor data con- sistency and detection limit. To solve these problems,the research dissolves samples using nitric aeid-perchloric acid- hydrofluoric acid, uses 2 % hydrochloric acid for leaching, 2 % diammonium hydrogen phosphate - 2 % thiorea as matrix modifier, and finally uses graphite furnace atomic absorption to determine trace silver in geological samples; the method analyzed national primary reference substance and field samples and the results are satisfactory; the detection limit is 0.02 p^g/g,the recovery rate adding reference substance is 95.0 % to 98.3 % and the RSD is 4.56 % to 9.98 %. The test solvent regime is applicable to the determination of other elements with no need to additionally dis- solve samples which makes analysis simple and cost-effective. The method is simple, quick and accurate.