Which is the most suitable spectroscopic technique that I can use to determine the concentration of heavy metals in marine sediment, and which are the sample preperation techniques that I can use in prepering the following samples for the analysis; sea sand, corals and sea weeds?
The US Environmental Protection Agency has an entire compendium of detailed analytical techniques, including sample preparation/digestion. See:
https://www.epa.gov/hw-sw846/sw-846-compendium
The 6000 series discuss ICP methods, and the 7000 series discusses AA methods.
Digest the sample in aqua regia and make up the solution with HCl and use Atomic Absorption/emission spectrometer to quantify metals
I strongly suggest that you perform sequential extraction (heavy metal speciation) as well as total or pseudo-total metal analysis to determine the heavy metal concentration in your sediment samples. There are several sequential chemical fractionation schemes available. These are based on the sequential extraction procedure reported by Tessier et al. (1979) or the BCR sequential extraction procedure from the European Community's Bureau of References. My reason for advancing the use of sequential extraction method is because the chemical fractionation of a metal determines its mobility, bioavailability and the potential risks it poses to the environment and to human health. Extraction for total or pseudo-total metal concentration can be performed using aqua regia or the description given by S. Bhatt.
ICP-AES, ICP-MS or ICP-OES are reliable analytical methods for determination of metal concentrations. Refer attached for guidance on sequential extraction methods.
