Overview
EN ISO 5398-2:2009 sets out a standard method for the chemical determination of chromic oxide content in leather using colorimetric analysis. Developed by the European Committee for Standardization (CEN) in collaboration with ISO and international leather industry bodies, this standard details a precise and reproducible approach to quantifying total chromium, expressed as chromic oxide, in leather samples. The colorimetric method is applicable to leathers with chromic oxide contents above 0.05%, offering a reliable and internationally recognized procedure for laboratories engaged in leather quality assessment and regulatory compliance.
Key Topics
- Colorimetric Determination: The standard describes a photometric method using a spectrophotometer to measure the intensity of color formed by the reaction between chromium in leather and diphenyl carbazide.
- Scope of Analysis: Applies to all leathers expected to contain more than 0.05% chromic oxide, regardless of the chemical form or oxidation state of chromium present.
- Sample Preparation: Sampling is preferably conducted according to ISO 2418 and ISO 4044; accurate weighing and duplicate analyses are required for reliable results.
- Reproducibility: Duplicate tests on each sample are necessary, with strict guidelines on allowable variances to ensure high repeatability and confidence in results.
- Expression of Results: Chromic oxide content is reported as a percentage by mass on a dry matter basis, with optional reporting on a dry, degreased mass if required.
Applications
The EN ISO 5398-2:2009 standard is essential in several practical contexts within the leather industry:
- Quality Assurance: Enables tanneries and leather goods manufacturers to monitor and control chromium content in their products, ensuring consistent tanning quality and performance.
- Regulatory Compliance: Supports compliance with health, safety, and environmental regulations by providing a validated method to determine overall chromium levels, which is critical where chromium residue limits are specified.
- Laboratory Testing: Provides research and testing laboratories with a standardized procedure, ensuring results are reliable and can be compared or recognized globally.
- Product Certification: Forms a basis for certifying leather products to conform to international and national standards, enhancing market access and consumer trust.
- Environmental Auditing: Facilitates monitoring of chromium in effluents and finished leathers, supporting sustainable production and reduced environmental impact.
Related Standards
Organizations and laboratories using EN ISO 5398-2:2009 may also reference the following interrelated standards for comprehensive leather analysis:
- ISO 2418: Leather - Chemical, physical, mechanical, and fastness tests – Sampling location guidelines.
- ISO 3696: Water for analytical laboratory use – Specification and test methods.
- ISO 4044: Leather – Chemical tests – Preparation of chemical test samples.
- ISO 4684: Leather – Chemical tests – Determination of volatile matter.
- ISO 5398-1, -3, -4: Parallel parts of ISO 5398 describing alternative methods for chromic oxide determination, including titration, atomic absorption spectrometry, and ICP-OES.
Practical Value
By following EN ISO 5398-2:2009, organizations ensure that chromic oxide determination in leather is carried out in a consistent, accurate, and internationally accepted manner. This contributes to product reliability, regulatory compliance, and responsible environmental stewardship within the global leather industry.
Keywords: EN ISO 5398-2:2009, chromic oxide, leather analysis, colorimetric determination, chromium content, leather standard, leather quality control, CEN standards, ISO standards, leather chemical testing.