Overview
EN ISO 1833-27:2019 (ISO 1833-27:2018) specifies a quantitative chemical analysis method using aluminium sulfate to determine the mass percentage of cellulose fibres (natural or regenerated) in textile mixtures after removal of non‑fibrous matter. The method is applicable where cellulose is blended with polyester, polyamide, acrylic, wool and elastane. It is part of the ISO 1833 series on textile composition analysis and was adopted by CEN as a European Standard.
Key topics and technical requirements
- Principle: Cellulose fibres are selectively degraded (carbonized) by an aluminium sulfate/glycerol solution plus heat; the remaining non‑cellulosic residue is collected, washed, dried and weighed. Cellulose content is calculated by difference against the original dry mass.
- Reagents: Aluminium sulfate octadecahydrate (specified assay), glycerol, and guar gum are used to prepare the carbonization solution.
- Apparatus & conditions:
- Heated plate press operating at 160 ± 2 °C with defined pressure for carbonization.
- Mechanical shaker, stainless steel balls, square plastic bottles and a 120–150 µm standard sieve for removing and recovering residue.
- Wringer for ensuring complete impregnation of the specimen.
- Procedure highlights:
- Soak specimens in the carbonization solution, ensure adequate wet mass, press and heat for a defined time, then mechanically remove carbonized cellulose and recover residue for weighing.
- Microscopic examination of residue is recommended to confirm complete removal of carbonized cellulose.
- Safety & environment: The method offers a safer, more eco‑friendly alternative to hazardous solvents (e.g., concentrated acids, dimethylformamide) used in some selective dissolution methods.
- Traceability: Follow ISO 1833‑1 general principles for sampling, calculation and expression of results. Precision and validation data are included in the standard.
Applications and users
- Quality control laboratories in textile and apparel manufacturing for verifying fibre composition.
- Third‑party testing labs, inspection bodies and customs authorities checking fibre content claims and labeling compliance.
- R&D and product development teams assessing blends and recycling feedstock composition.
- Standards developers and conformity assessment organizations integrating composition analysis methods.
Keywords: textile quantitative chemical analysis, aluminium sulfate method, cellulose fibre content, textile testing, EN ISO 1833‑27:2019.
Related standards
- ISO 1833 series (general quantitative chemical analysis principles).
- ISO 1833‑1 (general principles and procedures referenced by this part).
Note: consult the full EN ISO 1833‑27:2019 text for complete technical details, safety warnings and normative references before implementation.
