Determination of Heavy Metals in Hair Dyes by the Atomic Absorption Spectrophotometry

Abstract

Heavy metals are present in our environment, and it is therefore difficult to avoid their presence and impact on the human organism. Some heavy metals are essential to the human body, but if not in high concentrations. It is known that heavy metals can be found in many cosmetic products, and one of these is hair colours, where they can enter the body through the skin and root of the hair. In this way, if they are in high concentrations in the body, they can cause various health problems. It is therefore more important to determine the content of heavy metals (Cd, Pb, Co, Zn and Fe) in hair dyes by using different types made by different manufacturers. Also, the aim of the paper is to compare the concentrations of heavy metals in the dyes used to produce brighter and darker hair shades. For determining the concentration of heavy metals, eight haircut dyes produced in 2015 were used, and they were purchased in markets and drug stores in Bosnia and Herzegovina. The analysis of heavy metals was done by the atomic absorption spectrophotometry method on the atomic absorption spectrophotometer “Perkin Elmer” AAnalyst-800 with Zeeman correction, flame technique. The samples were prepared by wet digestion in the microwave oven Anton Paar Multiwave 3000, in a mixture of nitric acid and hydrogen peroxide in a ratio of 1 mL H 2 O 2 and 6 mL HNO 3 . In all the analysed hair dyes’ samples, heavy metals Cd, Pb, Co, Zn and Fe were detected. The concentrations of heavy metals in the analysed hair colours were different, but there was no significant difference between the concentration of the metal in the same dyes’ shades from different manufacturers. Hair dyes producing the darker shades of hair have a higher content of heavy metals than those used to produce brighter shades. Also, low concentrations of toxic heavy metals Pb and Cd were detected in all samples, however these heavy metals were strictly forbidden to be used as material (EU Directive No 1223/2009) for the production of cosmetic products, including hair dyes. Thus, all these analysed cosmetic products should not be used because of a potential negative health effect.