Determination of cadmium, copper, and lead in sodium chloride food salts by flame atomic absorption spectroscopy.

A method for determination of Cd, Cu, and Pb in sodium chloride food salt samples has been developed. It consists of extraction in 4-methyl-2-pentanone of the complexes formed with ammonium pyrrolidine dithiocarbamate and further analysis of the extracts by flame atomic absorption spectroscopy. Detection limits in ng/g salt were 0.2 for Cd, 0.7 for Cu, and 10.0 for Pb. The coefficients of variation of 12 independent analyses were 13% for Cd (at a level of 0.4 ppb), 18% for Cu (1.6 ppb), and 5% for Pb (40 ppb). The recoveries were 100 +/- 0% for Cd, 115 +/- 14% for Cu, and 100 +/- 13% for Pb.