Determination of chromium, nickel, cadmium and lead in human hair by ICP-AES utilizing the graphite cup direct insertion technique

The ICP-AES utilizing graphite cup direct insertion technique was investigated for the determination of trace elements in human hair. The graphite cup used was characterized by a large volume capacity of 50μl, a cup wall thickness of 0.5 mm and a slender rod of 1 mm in diameter. A sample volume of 25μl was applied to obtain higher sensitivity. Compromised optimum operating conditions were studied in order to attain higher precision and lower detection limits as well as to eliminate matrix effects on the volatilization of sample and memory effects. The graphite cup direct insertion technique was applied to the analysis of Cd, Pb, Cr and Ni in the certified reference material (NIES No. 5) and the results agreed well with the certified values. This method was confirmed to be applicable to samples containing Ca and Al as major elements.