Overview
ISO 19050:2021 - Rubber, raw, vulcanized - Determination of metal content by ICP-OES describes a standardized laboratory method for measuring both major and trace metal contents in raw and vulcanized rubber (including latex) using ICP-OES (inductively coupled plasma - optical emission spectrometry). The standard covers the analytical principle, required reagents and apparatus, calibration, sample preparation (sampling, decomposition of organic matter), test procedure and reporting. It is intended to support accurate, reproducible detection of metals for product safety, environmental monitoring and quality control.
Key Topics
- Scope and principle: Quantification of metal concentrations by measuring characteristic optical emissions from analytes excited in an argon plasma (plasma temperature ~8 000 °C to 10 000 °C).
- Instrumentation: Requirements and components of an ICP-OES system - sample introduction (peristaltic pump, nebulizer, spray chamber), RF generator, torch, spectrometer and detector.
- Reagents and standards: Use of ultra-pure acids (nitric, hydrochloric, sulfuric), multi- and single-element primary standard solutions traceable to NIST or an NMI, ammonium oxalate and internal standards (e.g., yttrium).
- Sample preparation: Guidance for representative sampling of solid rubber and latex (referencing ISO sampling methods) and decomposition techniques to destroy organic matrix:
- Wet oxidation (detailed nitric/sulfuric acid digestion with ammonium oxalate treatment)
- Dry ashing
- Microwave digestion
- Calibration and quality control: External multipoint linear standardization per the calibration schedule (Annex A) and use of blanks and traceable standards.
- Safety and environmental cautions: Laboratory practice, handling corrosive reagents, and proper waste disposal considerations.
Applications
ISO 19050:2021 is used by:
- Materials testing laboratories performing trace metal analysis on rubber products and latex.
- Rubber manufacturers and compounders for quality control of raw and vulcanized goods.
- Regulatory and compliance bodies monitoring product safety, restricted substances and environmental impact.
- Research and development groups analyzing elemental impurities or studying additive/contaminant behavior.
Practical benefits include reliable multi-element detection, broad dynamic range, reduced matrix interferences versus other atomic techniques, and suitability for both trace and major element determination in rubber matrices.
Related Standards
- ISO 123 - Rubber latex - Sampling
- ISO 124 - Latex, rubber - Determination of total solids content
- ISO 1795 - Rubber, raw natural and raw synthetic - Sampling and preparative procedures
- ISO 18899:2013 - Guide to the calibration of test equipment
Keywords: ISO 19050:2021, ICP-OES, rubber metal content determination, vulcanized rubber testing, trace metals in rubber, sample digestion, wet oxidation, microwave digestion.