Analysis of Seawater for Dissolved Cadmium, Copper and Lead: an Intercomparison of Voltammetric and Atomic Absorption Methods

Bruland, K.W., Coale, K.H. and Mart, L., 1985. Analysis of seawater for dissolved cadmium, copper and lead: an intercomparison of voltammetric and atomic absorption methods. Mar. Chem., 17: 285--300. An intercomparison study of voltammetric and atomic absorption spectrometric methods for determining cadmium, lead and copper in seawater samples was conducted. The voltammetric approach utilizes differential pulse anodic stripping voltammetry using a rotating, glassy carbon, mercury film electrode under condit ions developed to minimize contaminat ion sources and to enhance sensitivity for seawater matrices. The atomic absorption approach involves a concentration step using either an organic solvent extract ion of metal di thiocarbamate chelates or a C h e l e x 1 0 0 c o l u m n with detection by graphite furnace atomic absorption spectrometry. Similar and consistent results were obtained using both methods for the three trace metals studied on a wide range of natural seawater samples. Both methods are comparable in sensitivity for cadmium and copper, however the voltammetric method is better suited for the analysis of lead in seawater because of its enhanced sensitivity and low blank. An advantage of the voltammetric approach is its amenabil i ty towards real-time shipboard analysis.