Accuracy and precision of lead isotopic composition measurements in seawater

摘要: Abstract Accurate and precise measurements of stable lead isotopic compositions in seawater are critically dependent upon the ultra-clean techniques developed for accurate low (0.1 ng kg −1 ) concentrations by thermal ionization mass spectrometry. These include both limiting measuring contamination during all phases sampling, storage analysis. Essential to this samplers shipboard facilities collecting uncontaminated samples, laboratory cleaning containers, purifying reagents processing samples standards. Techniques also required compensate absence an internal standard, refractory hydrocarbon contaminants limited sensitivity detectors. Adaptation those has lowered analytical detection limit analyses 0.02 . While precision these (0.1–0.4%) is less than that high isotope ratio (0.001%), it sufficient identify sources inputs ocean trace biogeochemical cycles within ocean. The accuracy initial data currently being established with interlaboratory calibrations evaluated terms its oceanographic consistency.