Simultaneously Direct Determination Trace Elements and its Distribution in Ancient Tooth Samples by Slurry Sampling-Electrothermal Vaporization Inductively Coupled Plasma Mass Spectrometry

Abstract.

A method was developed for the simultaneous and direct determination of some important trace elements Al, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba, La, Pb in ancient tooth samples and its distribution in dentine and enamel by slurry sampling fluorination assisted electrothermal vaporization inductively coupled plasma mass spectrometry (FETV-ICP-MS) with polytetrafluoroethylene (PTFE) as fluorinating reagent. To remove the organic composition in samples and separate the dentine and enamel, a simple cineration pretreatment (cineration temperature 500 °C) was involved prior to analysis. The matrix effect resulting from the major matrix element-Ca was investigated, and no remarkable matrix effect was found when the matrix concentration was smaller than 0.6 g L⁻¹. It was also found when Ca concentration was less than 0.4 g L⁻¹, the possible mass interference resulting from Ca can be negligible. The detection limits for 12 trace metal elements obtained by FETV-ICP-MS were 0.6(Cr)–19.2(Mn) ng · L⁻¹ with the precisions of 3.71% (Cr)−8.22% (Fe), c = 10 µg · L⁻¹, n = 9. The proposed method was used to directly determine the trace metal elements in ancient tooth samples (about 2000 years ago), and the analytical results are satisfactory.