沉淀分离-电感耦合等离子体质谱法测定方铅矿中铊

Determination of thallium in galena by precipitation separation combined with inductively coupled plasma mass spectrometry

当高浓度Pb共存时,采用四极杆ICP-MS测定Tl,由于^(204)Pb、^(206)Pb的强峰拖尾,分别干扰^(203)Tl、^(205)Tl的测定,使测定结果偏高。本文采用样品分解后加入硫酸,使大量Pb以PbSO_4沉淀形式与Tl分离,分取清液稀释后用ICP-MS测定,解决了测定方铅矿中Tl时Pb的干扰问题。方法检出限(3σ)为0.002μg/g,相对标准偏差(n=12)为3.5%~7.5%。通过与传统泡沫塑料吸附富集-石墨炉原子吸收光谱法比对验证,方法准确可靠。

When high concentrations of Pb were coexisted,the determination of Tl using quadrupole ICP-MS were on the high side due to the strong peak tailing of ^（204）Pb and ^（206）Pb which would interfere the determination of ^（203）Tl and ^（205）Tl. In this paper,sulfuric acid was added after the sample was decomposed. A large number of Pb would be precipitated in the form of PbSO_4 and separated from Tl. The supernatant was diluted for the measurement by ICP-MS. The method solved the determination of Tl in galena from the interference of Pb. The detection limit（ 3 σ） was 0. 002 μg / g,and the relative standard deviation（ n = 12） was 3. 5% ～ 7. 5%. The method was accurate and reliable comparing with the traditional foam adsorption-graphite furnace atomic absorption spectrometry.