Accurate and Precise Analysis of Trace Levels of Cu, Cd, Pb, Zn, Fe and Ni in Sea Water by Isotope Dilution Mass Spectrometry

摘要: Accurate and precise determinations of natural levels trace metals in sea water are highly reliant upon the size variability analytical blank, method for determining yield, and, to a lesser extent, inherent precision instrument used. Thermal source, isotope dilution mass spectrometry together with ultra-clean room techniques were successfully used Cu, Cd, Pb, Zn, Ni Fe water. Multi-element analyses performed single experiment owing differing release filament current each element. A Re loaded substrate silica gel phosphoric acid gave high (0.1% 0.5%) determination ratio, allowed low detection limits (from 0.02 fmol Cd 0.07 pmol Fe). Yields accurately uniquely determined same sample by addition two isotopically enriched spikes, one before, after an extraction. Blanks assessed as summation individual contributions separate experiments prior analysis. Simply obtaining value total blank contribution can be misleading generate larger errors. Rigorous clean procedures very blanks; 0.0002 nmol kg−1, 0.0005-0.002 Pb Cu 0.03 Zn kg−1 0.7 kg−1.