Time-resolved monitoring of heavy-metal intoxication in single hair by laser ablation ICP-DRCMS

The potential of laser ablation inductively coupled plasma mass spectrometry for the time-resolved analysis of heavy-metal intoxication in human bodies by analysis of hair is demonstrated. As application, we analyzed forensic samples from one individual after Hg intake and from one treated with a Pt-containing cytostatic remedy. Single hairs were analyzed from the hair root to the tip by laser ablation ICP-MS with a spatial resolution of 20 μm (corresponding to approx. 2 h growth of the hair). Sulfur was used as internal standard and was analyzed by using oxygen as reaction gas in the dynamic reaction cell of the ICP-DRCMS. The detection limits for Hg and Pt were found to be 0.3 μg g-1 and 0.5 ng g-1, respectively. Standard uncertainties for the quantification results were 10% for Hg and approximately 15 % for Pt. The analyzed hair samples reflected the forensic evidence in both cases. A significant increase of Hg concentration, by a factor of 50, at the time of HgO administration could be shown, and variation of Pt in the hair strands could be used to monitor the time and relative amount of Pt intake by the patient. The investigations also revealed that the concentrations in the outer and the inner parts of the hair varied similarly with time, even though the concentration in the core of the hair is approximately 0.25 that at the surface for both Pt and Hg.