Determination of mercury in hair by coupled CVAA-ICP-MS

Abstract

This paper describes the coupling of a cold vapour atomic absorption (CVAA) instrument with an ICP-MS to obtain mercury concentration information and stable isotopic ratio data. The sample preparation procedure, based on microwave digestion, describes the decomposition of small masses of hair using 7 ml digestion vessels, which will enable the methodology to be used subsequently with neonatal hair samples. The results based on a CRM hair sample and spiked real samples indicated that the digestion method with direct CVAA analysis gave recoveries of around 100% with a corresponding RSD of 3.5%. The interfacing of the CVAA instrument to the ICP-MS was relatively simple and enabled isotopic data to be obtained in tandem with CVAA quantitative data. Some ICP-MS mercury memory problems were observed with the coupled CVAA-ICP-MS but these did not affect either the CVAA determination or isotopic ratio estimations.