Flameless atomic absorption spectroscopic determination of heavy metals in whole-fish samples.

Flameless atomic absorption spectroscopy with a carbon rod atomizer was used to determine lead, cadmium, and chromium in whole-fish samples. Samples were dry-ashed, and the metals were separated by solvent extraction with ammonium pyrrolidine dithiocarbamate in methyl isobutyl ketone, and then back-partitioned into an aqueous acid solution for analysis. The back-partitioning step allows a direct comparison of sample solutions with aqueous solutions of the standard. Recoveries of the metals from fortified samples averaged 91% (+/-9.6) for lead and 100% (+/-5.6) for chromium at the 0.1-1 ppm level, and 100% (+/-13.3) for cadmium at the 0.01-0.1 ppm level.