Analytical Method of Pb Isotopes in Coal

As the basis method for the pollution source apportionment, the isotope ratios were applied for analysis Pb isotopes in coal to explore the feasibility of coal pollution source apportionment. A method was established to analysis Pb isotopes in coal. First, the coal samples were dissolved by the combination of ashing and microwave digestion. Then by using PB resin extraction chromatography, Pb and a large number of matrix elements were effectively separated. After separation, the Pb isotope ratios were determined by multi-collector inductively coupled plasma mass spectrometry. The Pb isotopic ratios of natural Pb solution were calibrated with NIST 981. Using established analytical method, the measured relative error of ²⁰⁸Pb/²⁰⁷Pb, ²⁰⁶Pb/²⁰⁷Pb in natural Pb solution were less than 0.03%, the decontamination coefficients of sodium, magnesium, aluminium, iron, titanium and manganese were more than 400. The results showed that the method was effective and reliable. By measuring the standard coal samples (NIST 1635a, NIST 1632d), Shanxi Datong and Panzhihua coal samples, it was found that the relative standard deviation of ²⁰⁸Pb/²⁰⁷Pb, ²⁰⁶Pb/²⁰⁷Pb were less than 0.2%. The ratio difference of ²⁰⁸Pb/²⁰⁷Pb and ²⁰⁶Pb/²⁰⁷Pb between Datong coal and Panzhihua coal was about 6%~10%. Such a big difference proved that it was feasible to establish a Pb isotope background database about the coal in China.