电感耦合等离子体质谱法测定甘肃文县阳山金矿床原生晕样品中金

甘肃文县阳山金矿床原生晕样品中的金含量在μg/g到ng/g之间变动,高值异常点多(0.5～15.4μg/g),测试过程金记忆效应问题突出.选择采用70 mL王水(1+1)对甘肃文县阳山金矿床原生晕样品进行消解,用聚氨酯泡沫塑料对金进行吸附富集,以3 g/L硫脲溶液进行脱附,以铼(5 ng/mL)为内标选择在线内标法进行...

Determination of gold in primary halo sample from Yangshan gold deposit in Wenxian County of Gansu Province by inductively coupled plasma mass spectrometry

The gold content in primary halo sample from Yangshan gold deposit in Wenxian County of Gansu Province varied from μg/g to ng/g. There are many high value outliers (0.5-15.4 μg/g), and the memory effect of gold in determination is outstanding problem. The primary halo sample from Yangshan gold deposit in Wenxian County of Gansu Province was digested with 70 mL of aqua regia (1+1). The gold was adsorbed and enriched with polyurethane foaming plastic followed by desorption with 3 g/L thiourea solution. The on-line internal standard method using rhenium (5 ng/mL) as internal standard was selected for correction. The determination of gold in primary halo sample from Yangshan gold deposit in Wenxian County of Gansu Province by inductively coupled plasma mass spectrometry (ICP-MS) was realized. The primary halo sample with relatively high gold content Y2-1(w(Au)=5.14 μg/g)] was determined according to the experimental method. Then the pipelines were cleaned with 2% nitric acid and 3 g/L thiourea solution before determination of blank. The results showed that the cleaning effect of 3 g/L thiourea solution was better than 2% nitric acid. When the cleaning time with 3 g/L thiourea solution was in range of 30-90 s, the value of blank was close to 0. Therefore, the pipelines were cleaned with 3 g/L thiourea solution for 30 s to eliminate the influence of memory effect of gold. The correlation coefficient of calibration curve was 0.999 8. The linear range was 0.12-500 ng/g. The limit of detection was 0.03 ng/g, and the limit of quantification was 0.12 ng/g. The contents of gold in seven certified reference materials of geochemical prospecting and gold for the analysis of gold were determined according to the experimental method. The results were consistent with the certified values. Three primary halo samples with different types (Y3-1 phyllite, Y3-2 tattered altered phyllite, and Y3-3 plagioclase granite porphyry gold ore) were selected and determined for 6 times according to the experimental method. Moreover, certain amount of gold standard solution was added for the recovery test. The relative standard deviations (RSD, n=6) of determination results were between 5.3% and 9.0%. The recoveries were between 90% and 105%. Three primary halo samples with different types were determined according to the experimental method, and compared with graphite furnace atomic absorption spectrometry (GFAAS). The determination results of two methods were basically consistent.