Aqua Regia Digest
A nominal 40g sample is digested in a mixture of Nitric and Hydrochloric Acids. This digest is performed using plastic bottles that are discarded after use, ensuring no cross contamination. The digest is diluted, mixed and an aliquot of the acid solution is taken and analysed directly by ICP-MS or ICP-OES for Gold and other elements.
As there is no organic solvent extraction, this technique will normally provide a Gold result that more closely agrees with Fire Assay.
Whilst being an effective way of determining Gold, this technique can also be used for a wide variety of elements. It must be borne in mind however, that this may not be a total digest.
Detection Limits by ICP-OES (Method Code : AR101)
| Ag(1) | Al(100) | As(5) | Ba(1) | Ca(100) | Cd(1) | Co(2) |
| Cr(5) | Cu(1) | Fe(100) | K(100) | Mg(100) | Mn(1) | Mo(2) |
| Na(100) | Ni(1) | P(20) | Pb(5) | S(50) | Sc(1) | Sr(1) |
| Ti(50) | V(2) | Y(5) | Zn(1) | Zr(1) |
Detection Limits by ICP-MS (Method Code : AR102)
| Ag(0.05) | As(0.2) | Ba(0.05) | Bi(0.02) | Cd(0.1) | Ce(10)* | Co(0.2) |
| Cs(20)* | Cu(0.5) | Dy(10)* | Er(10)* | Eu(2)* | Ga(0.2) | Gd(0.05)* |
| Hg(0.01) | Ho(5)* | In(5) | Ir(5)* | La(10)* | Li(0.1) | Lu(5)* |
| Mo(0.1) | Ni(1) | Nd(10)* | Pd(10)* | Pb(1) | Pr(5)* | Pt(5)* |
| Rh(5)* | Ru(5)* | Rb(0.05) | Sb(0.02) | Sc(0.5) | Se(1) | Sm(10)* |
| Sn(0.2) | Sr(0.1) | Tb(5)* | Te(0.1) | Th(10)* | Tl(10)* | Tm(5)* |
| U(10)* | W(0.1) | Y(10)* | Yb(10)* | Zn(1) |