APPLICATION OF ADSORPTIVE STRIPPING VOLTAMMETRY (ADSV) FOR THE ANALYSIS OF TRACE-METALS IN BRINE .1. BATCH VOLTAMMETRIC MEASUREMENTS

Routine analysis of brine for trace metals is important for safe and economical production in the alkali chloride electrolysis. As opposed to many spectroscopic techniques, trace metal determination by adsorptive stripping voltammetry (AdSV) is shown to be performed directly in brine. With minimal sample preparation chromium(VI), iron(III), nickel(II), cobalt(II), titanum(IV), manganese(II), molybdenum(VI) and vanadium(V) can be determined within minutes. The influence of parameters such as pH-value, supporting electrolyte solution, concentration of complexing reagents and possible interferents are investigated for optimal experimental conditions. Minimum detection limits are less than 5 ng/g for all trace metals except 1 ng/g for chromium(VI), cobalt(II) and molybdenium(VI) for 40 s adsorption periods with precisions of better than 7%. AdSV with linear or differential pulse scan is discussed.