ISO 13885-3:2020

Overview

ISO 13885-3:2020 - Gel permeation chromatography (GPC) - Part 3: Water as eluent - specifies a standardized method for determining the molar-mass distribution and average molar masses Mn (number average) and Mw (weight average) of water-soluble polymers by gel permeation chromatography (also known as size exclusion chromatography, SEC). The standard is intended for neutral polymers and polyanions (e.g., polycarboxylates, polysaccharides, fully hydrolyzed polyvinyl alcohols, high-molecular polyethylene oxides), and defines apparatus, calibration, sampling, data evaluation and reporting requirements when water is used as the mobile phase.

Key topics and technical requirements

• Scope and limitations
  • Applicable to polymers soluble in water; not applicable to polycations (e.g., chitosan).
  • Not suitable for samples with Mw > 1 × 10^6 g·mol−1 or polymers with elution limits outside the calibration range.
  • No peak-broadening correction methods included; use absolute techniques (membrane osmometry, light scattering) if absolute molar masses are required.
• Principle
  • Separation based on polymer coil size: larger molecules elute earlier; detector response (typically a differential refractive index) is converted to molar-mass distribution via a calibration curve.
• Apparatus & reagents
  • Components: eluent supply (degassed), pump (recommended flow 1 ml/min, flow variation ≤ 0.1%), injection system, separation columns, column temperature control, detector.
  • Sample preparation: polymer concentration in injected solution typically < 5 g·L−1.
• Calibration & data treatment
  • Requirements for calibration standards, preparation of calibration solutions, elution-volume measurement and plotting calibration curves.
  • Data acquisition, baseline determination, net chromatogram calculation, evaluation limits, and calculation of Mn, Mw and distribution curves.
• Quality & reporting
  • Precision (repeatability, reproducibility), required test-report content and equipment/data metadata.
• Informative annexes
  • Conversion for variant column sizes (Annex A), example standard datasheet (Annex B), and explanatory notes (Annex C).

Applications and users

• Routine quality control and specification testing in industries handling water-soluble polymers (paints & varnishes, adhesives, polymers, food additives, personal care).
• R&D and analytical laboratories characterizing polymer molecular-weight distributions.
• Manufacturers of GPC/SEC instrumentation and column suppliers implementing water-eluent methods.
• Regulatory and standards bodies referencing ISO procedures for inter-laboratory comparability.

Related standards

• ISO 13885 series (other parts)
• ISO 1513 (sample preparation)
• ISO 4618 (terms and definitions)
• ISO 15528 (sampling)

Keywords: ISO 13885-3:2020, gel permeation chromatography, GPC, size exclusion chromatography, water as eluent, molar-mass distribution, Mn, Mw, water-soluble polymers.