ISO 15096:2020 pdf download

ISO 15096:2020 pdf download.Jewellery and precious metals — Determination of high purity silver — Difference method using ICP-OES
1 Scope
This document specifies the analytical procedure for the determination of silver with a nominal content of and above 999 ‰ (parts per thousand). This document specifies a method intended to be used as the recommended method for the determination of silver of fineness of and above 999 ‰. For the determination of fineness of and above 999,9 ‰, 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 this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 11596, Jewellery — Sampling of precious metal alloys for and in jewellery and associated products
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
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 ‰). 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 ‰. For the determination of fineness of and above 999,9 ‰, 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 (HCl), 30 % to 37 % HCl (mass fraction).
5.2 Nitric acid (HNO 3 ), 65 % to 70 % HNO 3 (mass fraction).
5.3 Aqua regia (should be prepared just before use). Mix three volumes of hydrochloric acid (5.1) and one volume of nitric acid (5.2).
5.4 Stock solution A (shall not contain any chloride), Al, Cd, Cr, Cu, Fe, Mg, Mn (100 mg/l each) in 3 % to 7 % HNO 3 (5.2) (mass fraction).
5.5 Stock solution B (shall not contain any chloride), Ni, Sb, Se, Te, Ti (100 mg/l each) in 3 % to 7 % HNO 3 (5.2) (mass fraction).
5.6 Stock solution C (shall not contain any chloride), As, Bi, Co, Pb, Pt, Si, Sn, Zn (100 mg/l each) in 3 % to 7 % HNO 3 (5.2) (mass fraction).