Overview
EN ISO 11495:2019 - Jewellery and precious metals - describes a validated analytical procedure for the determination of palladium (Pd) in palladium alloys (nominal content up to 990 ‰) using ICP‑OES with an internal standard element. Prepared by ISO/TC 174 and endorsed by CEN, this standard is intended for assay and quality control of jewellery and precious‑metal products, including alloys covered by ISO 9202.
Key topics and technical requirements
- Analytical technique: Inductively Coupled Plasma Optical Emission Spectrometry (ICP‑OES) using an internal standard (example: yttrium).
- Scope: Pd determination in palladium alloys up to 990 parts per thousand.
- Sample preparation: At least two accurately weighed samples dissolved in aqua regia (HCl + HNO3) and made up to an exactly weighed mass; sample solutions mixed with internal standard and diluted to measuring volume.
- Reagents: Analytical‑grade hydrochloric acid (30–37%), nitric acid (65–70%), high‑purity palladium reference (≥999.9 ‰ recommended) and an yttrium compound (e.g., YCl3·6H2O) as internal standard.
- Calibration & bracketing: Use a bracketing sequence of at least two calibration standards (low and high) near the expected Pd content; recommended to prepare several standards and verify linearity.
- Instrumentation requirements: ICP‑OES capable of simultaneous Pd and internal standard line measurement with a minimum optical resolution of 0.02 nm; clean torch/spray chamber, stabilized plasma.
- Recommended emission lines: Pd - 340.458 nm, 351.694 nm, 360.955 nm (choose lines without interference); Y - 371.029 nm, 377.433 nm, 321.669 nm.
- Performance checks: Minimum stabilization and integration times specified; final relative standard deviation (RSD) should not exceed 0.3% after calculation.
- Equipment tolerance: Analytical balance with readability 0.01 mg.
Practical applications and users
This standard is directly applicable for:
- Assay laboratories and metal testing labs performing palladium content analysis in jewellery and investment products.
- Quality control in jewellery manufacturing and refining to verify alloy composition and ensure hallmarking compliance.
- Regulatory and customs authorities requiring validated methods for precious‑metal content verification.
- Standards bodies and accreditation laboratories for method validation and interlaboratory comparisons.
Benefits include reproducible, traceable palladium measurements, robust calibration using internal standardization, and clear procedural requirements for sample prep and instrument setup.
Related standards
- ISO 9202 - classifications of precious‑metal alloys (referred to in scope)
- ISO 11596 - sampling procedure for jewellery and precious metals (referenced for sampling)
- Previous editions: EN ISO 11495:2016 / ISO 11495:2014 (superseded)
For implementation, follow the full text of EN ISO 11495:2019 for detailed formulas, procedural tolerances and test reporting requirements.