Lead isotopic ratios have been used extensively in geological, geochronological, and archaeological studies. However, the classical anion exchange method for Pb isolation/purification using AG1-X8 resin cannot be directly adopted for high content organic samples such as crude oils, due to the fact that the sample matrices probably interact with the active sites in the resin. This results in low percentages of Pb being recovered during column separation and low-level sample purity, therefore affecting the precision of the MC-ICPMS isotopic ratio. For Pb isolation/purification from crude oil samples, at least 0.5 mL of the resin AG1-X8 is required to obtain high Pb recovery without fractioning during the analysis of crude oil. After evaluation of 5 different mass bias correction methods, the combination of Tl normalisation (exponential law) and standard bracketing was selected, providing a precision of 0.0039, 0.0014 and 0.0012 and accuracies (‰) of 0.001, 0.001 and 0.004 for 208/204Pb, 207/204Pb and 206/204Pb isotope ratios, respectively, in the analysis of a solution of 10 ng mL−1 SRM NIST 981 (n = 18). The proposed procedure allows the reliable determination of Pb isotope ratio in crude oil, asphaltene and kerogen samples, important in geochronological studies.
You have access to this article
Please wait while we load your content...
Something went wrong. Try again?