The speciation of inorganic and methylmercury in human hair by high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry

Inorganic and methylmercury content in human hair has previously been determined using different analytical techniques for each species. In this study a single method, allowing the separation and determination of mercury species in human hair, is developed. Using a HPLC-ICP-MS system it is possible to separate inorganic and methylmercury in hair, without any modifications to the existing instrumentation. The results showed that in order to determine methylmercury as well as inorganic mercury the hair sample must be cold digested with 2 ml of concentrated nitric acid plus 1 ml of hydrogen peroxide and that a minimum of 0.1 g hair is required. Hair washing procedures are also investigated to remove exogenously bound species. It is seen that when hair is soaked with simulated sweat solution containing both inorganic and methylmercury and then washed with 0.1 M HCl all the methylmercury, both existing and spiked, can be removed from the hair sample. However, only 65% of the spiked inorganic mercury can be removed by washing with 0.1 M HCl, the rest being irreversibly bound to the hair.