Overview
EN ISO 22518:2020 - Paints and varnishes: Determination of solvents in water‑thinnable coating materials specifies a gas‑chromatographic method for identifying and quantifying solvents in water‑thinnable paints and varnishes, binder solutions, emulsions and dispersions. Results are expressed as mass fraction (%) and, with the precision given in Clause 13, single components above 0.02 % (mass fraction) can be determined quantitatively. This method is explicitly not intended for determining overall VOC or SVOC content (see ISO 11890‑2 for VOC/SVOC).
Key topics and technical requirements
- Principle: Separation of solvent components by gas chromatography (GC) followed by quantification using the internal standard method.
- Sample types: Water‑thinnable paints, varnishes, binder solutions, emulsions and dispersions.
- Detection limits: Quantitative determination for single components > 0.02 % (mass fraction) with precision defined in Clause 13.
- Apparatus:
- GC suitable for capillary separation columns.
- Instrument parts in contact with sample must be chemically resistant (e.g., glass).
- Support for hot and cold injection systems depending on product type.
- For hot injection: variable‑temperature injection block with split/splitless capability; injection temperature controllable to ±1 K; adjustable and monitorable split ratio.
- Hot injection splitter inserts should contain silanized glass wool to retain non‑volatile constituents and prevent adsorption (cleaning/replacement required).
- Analytical steps: Sampling, sample preparation, choice of injection system, GC conditions, calibration, analysis and expression of results.
- Precision and reporting: Clause 13 provides repeatability and reproducibility data; test report requirements are specified.
Applications and practical value
- Quality control in paint and coatings production to verify solvent composition and batch consistency.
- Formulation development for R&D teams assessing solvent behavior in water‑thinnable systems.
- Contract laboratory testing for customer specifications and supplier verification.
- Regulatory and compliance checks where specific solvent concentrations need to be documented (note: not for total VOC/SVOC determination).
- Useful for troubleshooting production issues linked to solvent content (e.g., drying performance, film formation).
Who should use this standard
- Paint, varnish and coatings manufacturers
- Analytical and contract testing laboratories
- R&D and QC chemists working with water‑based coatings
- Standards and compliance officers managing product specifications
Related standards
- ISO 11890‑2 - Determination of VOC and SVOC (use for VOC/SVOC content)
- ISO 4618 - Paints and varnishes - Terms and definitions
- ISO 15528 - Sampling of paints, varnishes and raw materials
Keywords: EN ISO 22518:2020, gas chromatographic method, solvent determination, water‑thinnable paints, paints and varnishes, GC analysis, solvent quantification, 0.02% detection limit.
