石墨炉原子吸收法测定地球化学样品中的痕量金

Determination of Trace Amount of Gold in Geochemical Exploration Samples by GFAAS

试料经高温焙烧后,用王水(50%)在电热板上加热溶解,在王水溶液的体积分数φ(王水)为10～15%和少量三氯化铁的介质中,用聚氨酯泡沫塑料吸附,再用硫脲—盐酸(10g/L)溶液解脱,所得溶液用Z-2000石墨炉原子吸收测定痕量金。根据实验得到的最佳分析条件,方法检出限(3S)为0.1ng/g,精密度(RSD,n=12)低于8.0%,经国家一级标准物质(GAu-2、GBW07243～GBW07248)分析验证,结果与标准值相符。

The geochemical exploration sample was roasted and dissolved with aqua regia （1＋1）.Trace gold is adsorbed by polyurethane foam with 10%～ 15% aqua regia in the presence of ferric chloride and released in 10g/L thiourea-hydrochloric acid solution. Au is determined by Z-2000 graphite furnace atomic absorption spectrometry （GFAAS）. The detection limit of the method is 0.1 ng/g and the precision （n=12） is 8.0%. The method has been applied to the determination of trace gold in geological standard reference samples and the results are in good agreement with certified values.