Trace metal analyses in octocorals by microwave acid digestion and graphite furnace atomic-absorption spectrometry

Eight octocoral species from two reefs off the Venezuelan coast were analyzed to determine their Cd, Cu, Ni, Pb and Zn content. A microwave sample work-up procedure, including drying and acid digestion, was developed and found to be faster and more convenient than conventional methods. Accurate and precise results were obtained for the determination of the metals of interest, using graphite furnace atomic-absorption spectrometry (GFAAS) with L'vov platforms. The accuracy of the results was checked against synthetic standards prepared to simulate the matrix of the analyzed octocoral species. Standard deviation values for synthetically prepared standards were less than 1% in all cases. On the other hand, standard deviations for sample results were considerably higher due to heterogeneity of the samples and environmental conditions at the sampling sites.