Mobile Voltammetric Laboratory for Ship-Board and Shore-Based Analyses of Dissolved Copper

Abstract

Environmental Context. Determining concentrations of dissolved copper in seawater is of interest, because copper (i) affects the health of aquatic biota, and (ii) has the potential to act as a water mass tracer, a marker which can be used to follow the movement of water in oceans. In situ analyses of copper and other trace metals in seawater have become increasingly popular, because they circumvent potential contamination problems associated with sample collection, storage, and transport to off-site analysis locations. This paper describes the assembly of a low-cost, mobile laboratory utilizing adsorptive cathodic stripping voltammetry (AdCSV) for the real-time determination of total dissolved copper in surface waters. Abstract. The main advantages of using a mobile laboratory for the real-time analyses of copper in surface waters over classical discrete sampling include a reduction in the risk of sample contamination and significant savings in both time and money to the analyst. This paper outlines the development of a portable voltammetric laboratory, capable of deployment from ships or road vehicles, and an experimental method for the real time analysis of total dissolved copper in surface waters. It has been tested in estuarine and coastal waters to the west of Ireland and has proved suitable for the analysis of both fresh and marine waters. The system includes a trace metal-free sampling fish (for shipboard sampling), in-line filtration and UV-digestion units, and a voltammetric analyzer and electrode controlled by a portable PC. Analysis of samples is completed using adsorptive cathodic stripping voltammetry (AdCSV). Using this portable AdCSV laboratory, the high sample throughput – approximately three per hour with standard additions completed on every sample – means that for ship-board surveys good spatial coverage is possible without the need for time-consuming station stops. For van-based tidal surveys, the portable AdCSV laboratory is both straightforward and low in cost to deploy.