Determination of Nickel and Platinum Species in Electrolyte Solutions With Inductively Coupled Plasma Mass Spectrometry Coupled to Cation Exchange Chromatography

Abstract

Two methods utilizing cation exchange chromatography (CEC) coupled to inductively coupled plasma mass spectrometry (ICPMS) were developed in this thesis. The first method, for direct determination of trace nickel concentrations in alkaline electrolyte, was found to have a method detection limit for 58Ni of 0.5 μg L-1 in 0.5 M NaOH. When in KOH solutions of 2-6 M, a detection limit of 0.2 μg L-1 or better was achieved. The main issues with previous analysis of these solutions were suppression of the plasma due to the high amount of alkali species being introduced and degradation of the ICP components due to caustic OH-. These issues were overcome using a 6-port valve to divert the CEC effluent containing the Na+ or K+ and using a strong acid eluent, namely HNO¬¬3, to neutralize the sample. The second method was for the speciation analysis of Pt complexes in 0.5 M sulfuric acid, which bypasses the addition of complexing agents typically used in anion exchange methods by using CEC. The change in speciation of Pt in several standard solutions prepared from stocks of either tetrachloroplatinite (Pt II) or hexachloroplatinic acid (Pt IV) was monitored and optimization of the procedure was performed to maximize the sample throughput and the overall sensitivity for platinum.