锡试金-电感耦合等离子体质谱法测定铬铁矿石中铂族元素

采用锡试金富集、盐酸溶解锡扣, 建立了电感耦合等离子体质谱法(ICP-MS)测定铬铁矿石中铂族元素的方法。结果表明, 选用15 g Sn粉, 30 g Na₂CO₃, 20 g K₂CO₃, 20 g SiO₂, 40 g硼砂, 10 g面粉, 5 g CaO, 2 g CaF₂, 5 g NaCl作为试金配料的组分, 在1 100 ℃进行熔矿, 可以得到合格的锡扣;选择¹⁹⁵Pt、¹⁰⁵Pd、¹⁰¹Ru、¹⁰³Rh、¹⁸⁹Os和¹⁹³Ir为待测元素同位素, 以Lu(10 ng/mL)校正了基体效应和信号漂移的影响。方法检出限(以下单位均为ng/g)分别为:0.18(铂)、0.21(钯)、0.15(钌)、0.15(铑)、0.12(锇)、0.15(铱)。采用方法对铬铁矿石成分分析标准物质GBW07201和GBW07202进行测定, 结果与认定值一致, 各元素的相对标准偏差(RSD, n=12)在1%~10%之间。

Determination of platinum group elements in chromite by inductively coupled plasma mass spectrometry with tin fire assay

After enrichment with tin assay and dissolution of tin buckle with hydrochloric acid, a method for the determination of platinum group elements in chromite was established by inductively coupled plasma mass spectrometry(ICP-MS). It was found that qualified tin buckle could be formed when 15 g of Sn powder, 30 g of Na₂CO₃, 20 g of K₂CO₃, 20 g of SiO₂, 40 g of borax, 10 g of flour, 5 g of CaO, 2 g of CaF₂ and 5 g of NaCl were taken as the components of assaying ingredients and the ore was melted at 1 100 ℃. ¹⁹⁵Pt, ¹⁰⁵Pd, ¹⁰¹Ru, ¹⁰³Rh, ¹⁸⁹Os and ¹⁹³Ir were selected as the analyte isotopes, and Lu (10 ng/mL) was employed to correct the influence of the matrix effect and signal drift. The detection limits of this method (the unit being ng/g) were 0.18 (Pt), 0.21 (Pd), 0.15 (Ru), 0.15 (Rh), 0.12 (Os) and 0.15 (Ir), respectively. The method was applied to determination of chromite certified reference materials GBW07201 and GBW07202 for composition analysis. The results were consistent with the certified values , and relative standard deviation for each element (RSD, n=12) was in the range of 1%-10%.