流动注射-火焰原子吸收光谱法测定地质样品中的常量金

样品经室温烧至650℃高温后灼烧保持1.5 h,用浓王水溶解。用泡塑分两次吸附富集样品中的常量金,将富集同一样品中金的两块泡塑置于盛有10 mL 10 g/L硫脲溶液的玻璃试管中,沸水浴保持20 min,使金释放出来,所得溶液应用原子吸收分光光度计采用流动注射测定。对仪器的测定条件进行了优化比较。方法检出限(3σ)为0.022μg/g,精密度(RSD,n=11)小于8.0%,测定范围为0.05～60μg/g。经国家金矿石分析标准物质验证,其测定值与标准值基本一致。

Determination of Gold in Geological Samples by Flow Injection- Flame Atomic Absorption Spectrometry

Sample was combusted at 650℃ for 1.5 h and then dissolved by aqua regia.Two blocks of polyurethane foam(1.5 cm×1.0 cm×1.0 cm) were used to adsorb and enrich ordinary level amount of gold in sample solution for two times.Gold was released from the foam by keeping the foam in sulfourea solution for 20 min in boiling water bath,and determined by FAAS.The working conditions of the instrument were studied and optimized.The detection limit of the method was 0.022 μg/g(DF=1).The detection limit(3σ) and measurement range were 0.022 μg/g and 0.05~60 μg/g,respectively.The reliability of the method has been tested by determination of gold in National Standard Reference samples and the results are in agreement with certified values with precision of less than 8.0%RSD(n=11).