Determination of lead, cadmium and nickel in hennas and other hair dyes sold in Turkey

The concentrations of lead, nickel and cadmium in various hennas and synthetic hair dyes were determined by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS). For this purpose, 1 g of sample was digested using 4 mL of hydrogen peroxide (30%) and 8 mL of nitric acid (65%). The digests were diluted to 15 mL and the analytes were determined by HR-CS GFAAS. All determinations of Pb and Cd were performed using NH₄H₂PO₄ as a modifier. The analytes in hair certified reference materials (CRMs) were found within the uncertainty limits of the certified values. In addition, the analyte concentrations added to hair dye were recovered between 95 and 110%. The limits of detection of the method were 48.90, 3.90 and 12.15 ng g^-1 for Pb, Cd and Ni, respectively and the characteristic concentrations were 8.70, 1.42 and 6.30 ng g^-1, respectively. Finally, the concentrations of the three analytes in various synthetic hair dyes with different brands, shades and formulae as well as in two henna varieties were determined using aqueous standards for calibration. The concentrations of Pb, Cd and Ni in hair dyes were in the ranges of LOD-0.56 μg g^-1, LOD-0.011 ng g^-1 and 0.030-0.37 μg g^-1, respectively, whereas those in the two hennas were 0.60-0.93 μg g^-1, 0.033-0.065 ng g^-1 and 0.49-1.06 μg g^-1, respectively.