Determination of Lead Elemental Concentration and Isotopic Ratios in Coal Ash and Coal Fly Ash Reference Materials Using Isotope Dilution Thermal Ionization Mass Spectrometry

Abstract

The rapid expansion of coal-fired power plants around the world has produced a huge volume of toxic elements associated with combustion residues such as coal fly ash (CFA) and coal ash (CA), which pose great threats to the global environment. It is therefore crucial for environmental science to monitor the migration and emission pathway of toxic elements such as CFA and CA. Lead isotopes have proved to be powerful tracers capable of dealing with this issue. Unfortunately, up to now, few high precision lead isotope data of CFA and CA certified reference materials (CRMs) determined by using the double spike technique have been reported. Hence, to facilitate the application of lead isotopes in environmental science, it is indispensable and urgent to determine a suite of high precision Pb isotope ratios and Pb elemental contents for CFA and CA CRMs. Here, we measured lead isotope ratios from four CFA and CA CRMs using thermal ionization mass spectrometry (TIMS) combined with the 204Pb–207Pb double spike method. Lead isotope ratios values of CRMs (GBW11124, GBW08401, GBW11125d, and JCFA-1) covered wide variation ranges from 17.993 to 19.228 for 206Pb/204Pb, from 15.513 to 15.675 for 207Pb/204Pb, and from 38.184 to 39.067 for 208Pb/204Pb. Lead isotope ratios of these CRMs, except for GBW11124, show good external reproducibility (2 RSD, n = 8), which is better than 0.05% for 206Pb/204Pb and 207Pb/204Pb, 0.07% for 208Pb/204Pb, 0.04% for 206Pb/207Pb, and 0.05% for 208Pb/206Pb. The Pb concentrations of these CRMs were determined using 207Pb single spike method. The reproducibility (1 RSD, n = 4) of Pb elemental content was <0.60%. This indicates the distribution of Pb elements in these CRMs is homogeneous. With the exception of GBW11124, the suite of CRMs can be used for determining CFA and CA matrix composition for quality control of Pb isotope analyses.

A Highly Sensitive Zirconium Hydrogen Phosphate Emitter for Ni Isotope Determination Using Thermal Ionization Mass Spectrometry

“…In case of the Si-Al-B or Si-Al-P emitter, several poly-atomic isobaric interferences may possibly be formed. For example, 27 Al 31 P may be potentially formed in mass 58, 29 Si 31 P potentially in mass 60, and 30 Si 31 P potentially in mass 61. Usually, 56 Fe and 66 Zn should be monitored and subtracted from potential isobaric interferences.…”

“…Usually, 56 Fe and 66 Zn should be monitored and subtracted from potential isobaric interferences. 27 Al 29 Si and 27 Al 28 Si 11 B may be potentially formed in mass 56 and mass 66, which may affect the subtraction of Fe and Zn for purifying actual samples.…”