ISO 15096:2020 pdf download.Jewellery and precious metals Determination of high purity silver Difference method using ICP-OES.
ISO 15096 specifies the analytical procedure for the determination of silver with a nominal content of and above 999 %o (parts per thousand).
ISO 15096 specifies a method intended to be used as the recommended method for the determination of silver of fineness of and above 999 %o. For the determination of fineness of and above 999,9 %o, modifications described in Annex B apply.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of ISO 15096. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
Iso 1 1596,Jewellery — Sampling of precious metal alloys for and in jewellery and associated products
The sample is weighed and dissolved in nitric acid to prepare a 10 g/l solution (higher concentration is used for fineness of and above 999,9 %o). The suspension, which can be present in that solution, is isolated by centrifugation or microfiltration and dissolved in aqua regia. Both nitric and aqua regia solutions are analysed separately by ICP-OES and the total content of each impurity (see Table A.1 for wavelengths) in the sample is obtained by adding together the results of the two analyses. The silver content is obtained by subtraction of the total content of impurities in the sample from 1 000 %o. For the determination of fineness of and above 999,9 %o, modifications described in Annex B shall be applied.
5 Reagents
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity.
5.1 Hydrochloric acid (HC1), 30 % to 37 % HCI (mass fraction).
5.2 Nitric acid (H NO3), 65 % to 70 % HNO3 (mass fraction).
5.4 Stock solution A (shall not contain any chloride), Al, Cd, Cr, Cu, Fe, Mg, Mn (100 mg/i each) in 3 % to 7 % HNO3 (52) (mass fraction).
5.5 Stock solution B (shall not contain any chloride), Ni, Sb, Se, Te, Ti (100 mg/I each) in 3 % to 7 % HNO3 (52) (mass fraction).
5.6 Stock solution C (shall not contain any chloride), As, Bi, Co, Pb, Pt, Si, Sn, Zn (100 mg/I each) in
3 % to 7 % HNO3 (52) (mass fraction).
5.7 Stock solution D (shall not contain any chloride), Ga, Ge, Hg, In, Pd, TI (100 mg/l each) in 3 % to 7 % HNO3 (52) (mass fraction).
NOTE 1 Elements which do not need to be analysed can be omitted. Other elements can be added, provided they are stable and do not generate significant interferences.
NOTE 2 Stock solutions “A” to “D” are typically prepared by mixing 10 % (of the total volume) of each
1 000 mg/I monoelemental solution with 5 % of nitric acid (52) (volume fraction) and making up with water.
They can be kept for up to 12 months under proper storage conditions.ISO-15096-2020