Determination of Trace Metal Ion Concentrations in Seawater

Abstract

An experimental procedure is described for the pre-concentration of trace metal ions from seawater. The procedure is suitable for senior students in analytical chemistry/instrumental analysis. Hydrated iron (III) oxide is recommended for the coprecipitation of trace transition metal ions from aqueous solution. Chelating ion-exchange with Chelex-100 is similarly recommended. Both techniques have been successfully used here. After leaching the precipitate or desorbing the resin with nitric acid solution, the trace metal ion content of the concentrate is determined using a suitably sensitive analytical technique such as graphite furnace atomic absorption spectrophotometry. The values obtained are used to calculate the concentration of trace metal ions in the seawater.