Question

Bone consists of the protein collagen and the mineral hydroxyapatite, ${\mathbf{Ca}}_{\mathbf{10}}{\left({\mathrm{PO}}_4\right)}_{\mathbf{6}}{\left(\mathrm{OH}\right)}_{\mathbf{2}}$. The Pb content of archaeological humanskeletons measured by graphite furnace atomic absorption shedslight on customs and economic status of individuals in historicaltimes. ³⁷Explain why La³⁺ is added to bone samples to suppressmatrix interference in Pbanalysis.

Short answer

La³⁺ appears to be a releasing agent, as it preferentially reacts with ${\mathrm{PO}}_4^{2-}$ , releasing Pb²⁺ .

Step-by-step solution

Define release agent.

A release agent (also known as a release coating, release agent, or mould release coating) is a substance that prevents other materials from adhering to surfaces. Mould release, die-cast release, plastic release, adhesive release, tyre and web release are all procedures where it can help.

Explain why  La3+  is added to bone samples to suppress matrix interference in Pb  analysis.

To avoid the chemical matrix effect, La³⁺ is employed. By creating thermally stable compounds, ${\mathrm{PO}}_4^{2-}$ prevents the atomization of Pb²⁺ . La³⁺ appears to be a releasing agent, as it preferentially reacts with ${\mathrm{PO}}_4^{2-}$, releasing Pb²⁺ .