On-line electrolytic dissolution for lead determination in high-purity copper by isotope dilution inductively coupled plasma mass spectrometry Original Research Article

A flow injection system combining electrolytic dissolution (ED) and programmable isotope dilution (ID) for determination of lead in high-purity copper by inductively coupled plasma mass spectrometry (ED-ID-ICP-MS) is proposed. ED was performed employing a Teflon chamber in where a gold cathode was placed. Best electrolytic conditions were achieved by using an 1.5 mol L−1 nitric acid as electrolytic solution and applying 2.5 A (dc) current during 4 s. Lead was determined in the electrolytic dissolved sample, which has undergone on-line isotope dilution exploiting binary sampling approach. Isotope dilution was carried out measuring the isotope ratio 206Pb/208Pb before and after on-line addition of the 208Pb-enriched solution. Precision of isotope ratio measurements for a sample containing 7–70 μg Pb g−1 was characterized by relative standard deviation (R.S.D.) of 0.5% (n=3) and the proposed methodology presented an R.S.D. lower than 4% (n=9). Accuracy was assessed comparing obtained results with those obtained by conventional dissolution and no significant difference at 95% confidence level was observed.