Atomic Emission Analysis of Human Nails for the Content of Trace Elements

To obtain data on the concentrations of trace elements in a human body, different biological samples are used; however, nails have some advantages. An optimized procedure is developed for the acid mineralization of human nails for the subsequent determination of trace elements therein by arc atomic emission spectrometry with excitation of a spectrum of a dry mineralization residue from the end of a carbon electrode. A mixture of conc. HNO₃ (1 mL) and conc. H₂O₂ (0.1 mL) was shown to be an optimum reagent for the decomposition of a nail sample with a weight of 0.1 g. The efficiency and process features of acid decomposition upon heating on a plate and in a microwave oven were compared. Seventy three nail samples were analyzed for the contents of Ag, Al, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn according to the developed procedure. The calculated statistically average contents and concentration ranges of the above-mentioned elements were compared with data of other publications.