Analytical Sciences

Analysis of Lead in Tooth Enamel by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry

Tsutomu URYU,* Jun YOSHINAGA,*  Yukio YANAGISAWA,* Masahiko ENDO,** and Junichi TAKAHASHI**

*Institute of Environmental Studies, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
**Yokogawa Analytical Systems Inc., 9-1 Takakura-cho, Hachioji, Tokyo 192-0033, Japan

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to determine the Pb/Ca ratios in the enamel of deciduous incisors, a biomarker of in utero Pb exposure, using pelletized bone certified reference materials (CRMs) as calibrants. The detection limit for Pb by LA-ICP-MS was 11 µg kg^-1 demonstrating an adequate sensitivity for Pb in the teeth of unexposed individuals (0.1 - 10 mg kg^-1). The precision for the Pb/Ca ratios in NIST SRM 1486 Bone Meal was 3.4%. The correlation between Pb/Ca ratios obtained by LA-ICP-MS and those obtained by a digestion method was highly significant. We found one point calibration by a CRM was applicable for the quantification of Pb in tooth enamel. This method will be valuable for the assessment of in utero Pb exposure levels.

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