封闭溶矿-电感耦合等离子体质谱法测定地质样品中金银铂钯

通过高压密闭溶解样品,建立了一次溶解样品后直接用电感耦合等离子体质谱法(ICP-MS)对地质样品中Au、Ag、Pt、Pd进行测定的方法。实验表明,于200 mL的高压密闭溶样罐中加入10.00 g样品后,通过加入30 mL HCl、5.0 mL H₂O₂、2.0 g KClO₃,及在160 ℃的恒温数显鼓风干燥箱中保温6 h,可将地质样品溶解完全;将样品消解液用由活性炭、改性活性炭、717阴离子交换树脂组合而成的新型组合富集剂分离富集及通过选择合适的测定同位素或数学校正方法消除质谱干扰后,可实现ICP-MS对地质样品中Au、Ag、Pt、Pd的测定;Au、Ag、Pt、Pd的校准曲线相关系数均不小于0.999 5,方法检出限分别为Au 0.097 ng/g、Pt 0.14 ng/g、Pd 0.17 ng/g、Ag 0.082 ng/g。将实验方法应用于铂族元素地球化学一级标准物质中Au、Ag、Pt、Pd的测定,结果与认定值相符,12次测定的相对标准偏差(RSD)不大于14.2%,将实验方法应用于地球化学一级标准物质和实际样品中Au、Ag、Pt、Pd的测定,回收率为92%～110%

Determination of gold,silver, platinum and palladium in geological samples by inductively coupled plasma mass spectrometry with sealed dissolution

After the sample was dissolved in high pressure sealed system, a direct determination method of Au, Ag, Pt and Pd in geological samples was established by inductively coupled plasma mass spectrometry (ICP-MS). The experimental results showed that, 10.00 g of geological samples could be fully dissolved by adding 30 mL of HCl, 5.0 mL of H₂O₂ and 2.0 g of KClO₃ in 200 mL high pressure sealed tank, which was put in constant temperature digital drying oven at 160 ℃ for 6 h. The sample digestion solution was separated and enriched with novel composite adsorbent composed of activated carbon, modified activated carbon and 717 anion exchange resin. Then the mass spectrometry interference was eliminated by selecting proper isotopes or mathematic correction. Consequently, the determination of Au, Ag, Pt and Pd in geological samples was realized by ICP-MS. The correlation coefficients of calibration curves of Au, Ag, Pt and Pd were not less than 0.999 5. The detection limit of Au, Ag, Pt and Pd was 0.097, 0.14, 0.17 and 0.082 ng/g, respectively. The proposed method was applied to the determination of Au, Ag, Pt and Pd in geochemical primary reference materials of platinum family element, and the results were consistent with the certified values. The relative standard deviation (RSD, n=12) was not more than 14.2%. The experimental method was applied to the determination of Au, Ag, Pt and Pd in geochemical primary reference materials and actual samples, and the recoveries were between 92% and 110%.