Overview
ISO 7012-3:2025 specifies analytical methods for the determination of in-can isothiazolinone preservatives in water-dilutable coating materials (paints and varnishes) and related products, including polymer dispersions. The standard defines required apparatus, sample preparation and extraction, and chromatographic determination using liquid chromatography with UV/VIS detection (LC-UV/DAD) and liquid chromatography coupled to mass spectrometry (LC‑MS or LC‑MS/MS). Applicable ionization techniques include electrospray (ESI) and atmospheric pressure chemical ionization (APCI).
Key topics and technical requirements
- Scope and applicability: Targeted at in‑can preservative analysis in water‑based coatings and polymer dispersions; the standard is part of the ISO 7012 series.
- Principle: Homogenize and extract samples with an appropriate solvent, purify by centrifugation, then identify and quantify isothiazolinones by LC‑UV or LC‑MS(/MS).
- Sample preparation & apparatus:
- High‑speed centrifuge (e.g., 5 000–30 000 r/min noted as suitable)
- Ultrasonic water bath (35–45 kHz)
- Analytical balances, volumetric flasks (10–100 ml), 0.22 µm filtration membranes
- Chromatography & detection:
- Reverse phase C18 analytical columns (HPLC/UPLC/UHPLC compatible)
- LC‑UV/DAD method and LC‑MS or LC‑MS/MS (single or tandem quadrupole)
- LC‑MS requires LC‑MS grade solvents
- Quality control & method performance:
- Requirements for blanks, calibration procedures, interferences assessment and calculation
- Precision statements including repeatability and reproducibility limits (method validation and interlaboratory testing are addressed)
- Documentation: Test report contents and annexes give example LC conditions, MRM setups, extraction mechanics and interlaboratory results.
Practical applications and users
ISO 7012-3:2025 is intended for:
- Quality control laboratories in paint, varnish and coating manufacturing verifying preservative content
- Regulatory and compliance testing where control of in‑can biocides (isothiazolinones such as MIT/MBC etc.) is required
- R&D teams developing water‑dilutable coatings and polymer dispersions to optimize preservative performance and stability
- Third‑party testing labs performing routine or contract analyses using HPLC/UPLC with UV and MS detection
Practical benefits include standardized extraction and chromatographic procedures, harmonized reporting, and traceable calibration for consistent preservative measurement across laboratories.
Related standards
Keywords: paints and varnishes, in‑can isothiazolinones, preservatives, LC‑UV, LC‑MS, LC‑MS/MS, HPLC, UPLC, polymer dispersions, analytical methods.
Open preview (PDF)Paints and varnishes — Determination of preservatives in water-dilutable coating materials — Part 3: Determination of in-can isothiazolinones with LC-UV and LC-MS