铅试金富集-塞曼石墨炉原子吸收光谱法测定矿石样品中铂钯铑铱

Determination of platinum,palladium,rhodium and iridium in mineral samples by Zeeman graphite furnace atomic absorption spectrometry after the preconcentration with lead fire assaying

建立了铅试金富集-塞曼石墨炉原子吸收光谱法测定矿石样品中铂、钯、铑、铱的新方法。运用传统的铅试金方法熔融分解矿石样品，且采用留铅灰吹的方法使样品中铂、钯、铑、铱富集在约3mg的铅合粒中。先用HNO3溶解铅合粒，再加入HCl以形成王水溶解，使铂、钯、铑、铱完全进入溶液，然后采用塞曼石墨炉原子吸收光谱法于选定的仪器参数条件下测定。本方法运用二次方程最小二乘法拟合校准曲线，曲线拟合良好。铂、钯、铑、铱的校准曲线拟合系数分别为0．9999、0．9999、0．9992、0．9994；特征浓度分别为1．8542ng／mL、1．5435ng／mL、0.4883ng／mL、0．4811ng／mL；相对标准偏差为：Pt 1．5％～4．5％、Pd 1．1％～2．9％、Rh 3．4％～6．3％、Ir 2．9％～5．8％。运用本方法测定标准物质中铂、钯、铑、铱含量，测定结果与认定值相吻合。

A novel method for determining platinum palladium, rhodium and irdium in mineral sample was established using Zeeman graphite furnace atomic absorption spectrometry. Mineral sample was melten using traditional lead fire assaying, and platinum, palladium, rhodium and irdium was accumulated in 3 mg of lead by cupellation. This alloy was dissolved in HNO3, and then HCl was added to form aqua regia solution to make sure that platinum, palladium, rhodium and irdium were fully dissolved in this solution. The concentration of the above four elements was detected at the selected instrumental parameters using Zeeman graphite furnace atomic absorption spectrometry. A calibration curve was created based on linear least squares fitting technique with a satisfactory curve fitting effect. The standard correlation coefficients are 0. 999 9, 0. 999 9, 0. 999 2 and 0. 999 4,and the characteristic concentration is 1. 854 2 ng/mL, 1. 543 5 ng/mL, 0. 488 3 ng/mL, and 0. 481 1 ng/mL for platinum, palladium, rhodium and irdium, respectively. The relative standard deviations （n = 4） are 1.5%- 4.5% （Pt）, 1.1%-2.9% （Pd）, 3.4%-6.3% （Rh）, 2.9%-5.8% （Ir）. The concentration of platinum, palladium, rhodium and irdium of standards material detected by this method is consistent with the certified value.