Question

Bone consists of the protein collagen and the mineral hydroxyapatite, ${\mathbf{Ca}}_{\mathbf{10}}\left({\mathrm{PO}}_4\right){\left(\mathrm{OH}\right)}_{\mathbf{2}}$. The content of archaeological human skeletons measured by graphite furnace atomic absorption sheds light on customs and economic status of individuals in historical times. 37Explain why${\mathbf{La}}^{\mathbf{3}\mathbf{+}}$is added to bone samples to suppress matrix interference in Pbanalysis.

Short answer

${\mathrm{La}}^{3+}$ appears to be a releasing agent, as it preferentially reacts with ${\mathrm{PO}}_4^{2-}$, releasing ${\mathrm{Pb}}^{2+}$ .

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   analysis.

To avoid the chemical matrix effect, ${\mathrm{La}}^{3+}$is employed. By creating thermally stable compounds, ${\mathrm{PO}}_4^{2-}$ prevents the atomization of ${\mathrm{Pb}}^{2+}$. ${\mathrm{La}}^{3+}$appears to be a releasing agent, as it preferentially reacts with ${\mathrm{PO}}_4^{2-}$, releasing ${\mathrm{Pb}}^{2+}$.