ISO 1833-15:2019 PDF

Overview

ISO 1833-15:2019 specifies a quantitative chemical analysis method for determining the composition of textiles that are mixtures of jute and certain animal fibres (wool and/or hair). The method calculates the proportion of each component by determining the total nitrogen content (Kjeldahl principle) after removal of non-fibrous matter. This part of ISO 1833 is a complete standalone procedure because its principle (nitrogen determination) differs from the selective-solubility methods in ISO 1833‑1. Note: the method is not applicable to products containing nitrogenous dyestuffs or nitrogen-containing finishes.

Key Topics and Requirements

• Scope and applicability
  • Mixtures of jute with wool and/or hair; animal-fibre component may be hair, wool, or their blend.
  • Excludes textiles with nitrogen-containing dyes or finishes.
• Sample preparation
  • Representative reduced laboratory sample per ISO 5089.
  • Solvent extraction in a Soxhlet (toluene:methanol 1:3) and aqueous extraction to remove non-fibrous matter.
  • Drying to constant mass before analysis.
• Analytical principle
  • Kjeldahl mineralization (H2SO4 with potassium sulfate and selenium dioxide) to convert organic nitrogen to ammonium sulfate.
  • Alkaline distillation and trapping in boric acid, followed by titration with standardized sulfuric acid.
  • Use of Kjeldahl distillation apparatus and titrator (accuracy ~0.05 ml).
• Calculations
  • Percent nitrogen in the dehydrated test portion computed from titration volumes and acid concentration.
  • Conversion to fibre composition using prescribed nitrogen contents: jute = 0.22% N, animal fibres = 16.2% N, and the provided formula (ISO 1833-15:2019) to calculate percent animal fibre.
• Reagents and safety
  • Analytical-grade reagents: toluene, methanol, sulfuric acid, potassium sulfate, selenium dioxide, NaOH, boric acid.
  • Safety precautions for toxic solvents and strong acids required.

Applications and Users

• Textile testing laboratories performing composition analysis for incoming materials, incoming quality control, and product verification.
• Manufacturers of blended jute products who need accurate blend ratios for labelling, process control, and quality assurance.
• Standards and conformity bodies verifying compliance with product specifications or regulations.
• Industry R&D and forensic textile analysts requiring reliable quantitative composition data where selective-solubility methods are unsuitable.

Keywords: ISO 1833-15:2019, textiles quantitative chemical analysis, jute blends, nitrogen determination, Kjeldahl method, Soxhlet extraction, textile composition analysis.

Related Standards

• ISO 1833-1 - General principles of quantitative chemical analysis of textiles (selective solubility methods).
• ISO 5089 - Preparation of reduced laboratory samples and test specimens for chemical tests.