Development of a Field Preconcentration/Elution Unit for Routine Determination of Dissolved Metal Concentrations by ICP‐OES in Marine Waters: Application for Monitoring of the New Caledonia Lagoon

Abstract

An iminodiacetate chelating resin was optimised for the rapid determination of Co, Cu, Fe, Mn and Ni in seawater. Using inexpensive, high‐capacity, reusable cartridges allowed high flow rates of up to 25 ml min−1. High preconcentration factors, of up to 500, were obtained in order to analyse samples using an ICP‐OES. The requirement for a buffer was eliminated due to the high tolerance of the ICP‐OES to interfering matrix elements, thereby further reducing the potential for contamination. Quantification limits in seawater were: Co = 6 ng l−1, Cu = 8 ng l−1, Fe = 6 ng l−1, Mn = 5 ng l−1 and Ni = 6 ng l−1. The method was verified by the analysis of near shore seawater (CASS‐4) and open ocean seawater (NASS‐5) reference materials. In order to satisfy the high sampling demands using the iminodiacetate cartridges, a portable off‐line preconcentration unit was developed for routine analysis. The multi‐channel preconcentration unit, was capable of treating up to eight samples simultaneously with concentrating times as little as 30 minutes. The technique was also used to determine dissolved metals in fresh and interstitial waters. The technique has been successfully used in a number of environmental studies and impact assessments to evaluate the effects of mining on the New Caledonian lagoon.