Determination of Fluorine Distribution in Shark Teeth

Published on
05 July 2022

Determination of Fluorine Distribution in Shark Teeth by Laser Induced Breakdown Spectroscopy

Benjamin T Manard, Christopher J Hintz, C Derrick Quarles, Jr, William Burns, N Alex Zirakparvar, Daniel R Dunlap, Toya Beiswenger, Alicia M Cruz-Uribe, Joseph A Petrus, Cole R Hexel


Quantifying the chemical composition of fast-growing hard tissues in the environment can shed valuable information in terms of understanding ecosystems both prehistoric and current. Changes in chemical composition can be correlated with environmental conditions and can provide information about the organism’s life. Sharks can lose 0.1 to 1.1 teeth per day, depending on species, which offers a unique opportunity to record environmental changes over a short duration of time. Shark teeth contain a biomineral phase that is made up of fluorapatite (Ca5(PO4)3F), and the distribution of F distribution within the tooth can be correlated to tooth hardness. Typically, this is determined by bulk acid digestion, energy-dispersive X-ray spectroscopy (EDS), or wavelength dispersive spectroscopy (WDS). Here we present laser induced breakdown spectroscopy (LIBS) as an alternative and faster approach for determining F distribution within shark teeth. Using a two-volume laser ablation chamber (TwoVol3) with innovative embedded collection optics for LIBS, shark teeth were investigated from sand tiger (Carcharias Taurus), tiger (Galeocerdo Cuvier), and hammerhead sharks (Sphyrnidae). Fluorine distribution was mapped using the CaF 603 nm band (CaF, Β 2Σ+ → X 2Σ+) and quantified using apatite reference materials. In addition, F measurements were cross referenced with EDS to analyses validate the findings. Distributions of F (603 nm), Na (589 nm), and H (656 nm) within the tooth correlate well with the expected biomineral composition and expected tooth hardness. This rapid methodology could transform the current means of determining F distribution, particularly when large sample specimens (350 mm2, presented here) and large quantities of specimens are of interest.

Metallomics, mfac050, DOI: 10.1093/mtomcs/mfac050


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