SIST EN ISO 6923:2024 PDF

Overview

EN ISO 6923:2024 - Paints and varnishes: Determination of monomeric diisocyanate content in coating materials and similar products using high performance liquid chromatography with ultraviolet detection (HPLC‑UV) - specifies a validated analytical procedure for quantifying monomeric diisocyanates in coatings, adhesives and other liquid or pasty matrices. The method covers common diisocyanates (MDI, TDI, IPDI, HDI) and uses derivatization with p‑nitrobenzyl‑N‑propylamine (PNBPA) followed by ultra high performance liquid chromatography (UHPLC/HPLC‑UV) for detection.

Key topics and technical requirements

• Scope and analytes: Quantification of methylene diphenyl diisocyanate (MDI - 2,4’ and 4,4’), toluene diisocyanate (TDI - 2,6 and 2,4), (cis/trans) isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI - 1,6) in various matrices.
• Reportable range: Mass fraction range from 0.01 % to 2.0 %; higher concentrations require dilution prior to derivatization.
• Sample prep principle: Direct weighing into acetonitrile, derivatization with PNBPA in dry acetonitrile (1:1 v/v), filtration and HPLC injection.
• Instrumentation: UHPLC/HPLC system (up to 600 bar) with quaternary gradient pump and multiple‑wavelength UV detector. Typical column specified: C18, 100 Å, 2.6 µm, 100 × 3 mm.
• Chromatography parameters: Mobile phases include 40 mM sodium acetate (pH ~4.5), water and acetonitrile with a specified gradient; detection commonly at 275 nm (TDI, IPDI, HDI) and 250 nm (MDI). Injection volume and flow rates are defined for reproducible quantification.
• Accessories and reagents: HPLC‑grade acetonitrile, nylon 0.20 µm filters, glassware, molecular sieves, PNBPA‑HCl derivative reagent and other chemicals listed.
• Validation and reproducibility: Method development and interlaboratory testing (including FEICA studies) demonstrated reproducibility and accuracy for low monomer contents.

Applications and users

This standard is designed for:

• Quality control and release testing in paints, varnishes and adhesives manufacturing
• Analytical and contract testing laboratories performing diisocyanate monitoring
• Regulatory and compliance testing related to occupational health, product safety and environmental reporting
• Research and development groups assessing formulation safety and residual monomer levels

Practical benefits include robust quantification of free monomeric diisocyanates to support product safety declarations, formulation optimization and compliance with workplace exposure and chemical regulations.

Related standards

• ISO 4618 - Paints and varnishes - Vocabulary
• ISO 15528 - Sampling of paints, varnishes and raw materials

Keywords: EN ISO 6923:2024, HPLC‑UV, UHPLC, monomeric diisocyanate, PNBPA derivatization, MDI, TDI, IPDI, HDI, coatings analysis, quantitative determination.