Overview
ISO 11495:2019 specifies an analytical procedure for the determination of palladium (Pd) in palladium alloys (nominal content up to 990 ‰) using inductively coupled plasma optical emission spectrometry (ICP‑OES) with an internal standard element. The method is applicable to jewellery and precious‑metal alloys (including those defined in ISO 9202) and defines sample preparation, calibration by bracketing, measurement, calculation and reporting requirements.
Key topics and technical requirements
- Scope: Measurement of Pd in palladium alloys up to 990 parts per thousand (‰).
- Principle: Internal standardization-measure intensity ratios of Pd and an internal standard (e.g. yttrium) and determine Pd mass by bracketing between two calibration points.
- Reagents and sample prep:
- Dissolution in aqua regia (HCl + HNO3) for both samples and Pd calibration standards.
- Use high‑purity palladium (≥ 999.9 ‰) for standards; prepare internal standard (yttrium) solution (~6 mg/L or prepared from YCl3·6H2O).
- Maintain consistent acid concentration between calibration and sample solutions.
- Equipment:
- ICP‑OES capable of simultaneous Pd and internal‑standard line measurement with optical resolution ≥ 0.02 nm.
- Analytical balance with 0.01 mg readability.
- Measurement parameters:
- Bracketing sequence using low and high standards around the expected sample Pd content.
- Minimum stabilization time 30 s; minimum integration time 10 s; at least 3 integrations per measurement.
- Recommended Pd emission lines: 340.458 nm, 351.694 nm, 360.955 nm. Recommended Y lines: 371.029 nm, 377.433 nm, 321.669 nm. Choose lines free of interferences.
- Quality limits and calculations:
- Intensity‑ratio mean (from five cycles) must have RSD ≤ 0.3%.
- Final Pd mass result RSD ≤ 0.30%; duplicate determinations should differ by less than 3 ‰.
- Results are reported as parts per thousand (‰) by mass, with required test‑report elements (sample ID, method reference ISO 11495:2019, results, deviations, etc.).
- Safety: Use appropriate laboratory health and safety measures when handling strong acids and aqua regia.
Applications and users
ISO 11495:2019 is intended for:
- Assay and quality control laboratories in the jewellery and precious‑metals sector.
- Assay offices and certification bodies determining palladium fineness and composition.
- Metallurgical and analytical laboratories performing routine or forensic Pd alloy analysis.
Practical applications include fineness verification, material certification, quality assurance during manufacturing, and regulatory compliance testing.
Related standards
- ISO 9202 - Jewellery and precious metals: fineness of precious metal alloys (referenced for alloy definitions).
- ISO 11596 - Sampling of precious metal alloys for and in jewellery and associated products (sampling procedures referenced).
Keywords: ISO 11495:2019, palladium determination, palladium alloys, ICP‑OES, internal standard, yttrium, aqua regia, bracketing calibration, jewellery testing, precious metals analysis.
Open preview (PDF)Jewellery and precious metals — Determination of palladium in palladium alloys — ICP-OES method using an internal standard element
