Overview - ISO 15373:2024 (Plastics - Polymer dispersions - Determination of free formaldehyde)
ISO 15373:2024 specifies two validated analytical methods for the determination of free formaldehyde (HCHO) in polymer dispersions. The standard applies to common dispersion types - including acrylic, acrylonitrile–butadiene, carboxylated styrene–butadiene and vinyl acetate dispersions - and can be used with other polymer dispersion compositions. Two complementary procedures are defined:
- Method A (UV/Vis spectrometer): direct derivatization with 2,4‑pentanedione and absorbance measurement at 410 nm for samples with free formaldehyde > 10 mg/kg.
- Method B (HPLC with post‑column derivatization): reversed‑phase separation (C18) with a post‑column Nash reagent and UV detection at 410 nm for low-level determinations and arbitration testing.
Keywords: ISO 15373:2024, free formaldehyde, polymer dispersions, UV/Vis spectrometer, HPLC, formaldehyde determination.
Key technical topics and requirements
- Sample preparation: separation of polymer phase from aqueous phase by filtration, coagulation or centrifugation (high-speed up to 50 000 r/min or low-speed ~1 000 r/min as appropriate), followed by microfiltration (≤0.1 µm).
- Derivatization chemistry: formaldehyde reacts with 2,4‑pentanedione to form a lutidine derivative detectable at 410 nm.
- Reagents and solutions: Nash reagent composition, Carrez clarification (potassium ferrocyanide / zinc sulfate), phosphate buffer mobile phase, and preparation/storage guidance (stock and standards refrigerated; fresh standards weekly).
- Calibration and quantification: external calibration with at least five standards (typically 1–15 mg/kg); Method A suited for >10 mg/kg, Method B for lower concentrations and arbitration. Method B includes precision estimates, repeatability and reproducibility requirements.
- Interferences: Method A can be affected by high levels (≈100×) of acetaldehyde or glyoxylic acid; Method B offers chromatographic specificity to separate potential interferents.
Practical applications and users
ISO 15373:2024 is intended for:
- Quality control (QC) and product safety testing in polymer dispersion manufacturing.
- Regulatory compliance testing where formaldehyde limits apply.
- Contract testing laboratories and R&D labs developing dispersion formulations.
- Arbitration and dispute resolution analyses (Method B recommended).
Practical uses include batch release testing, supplier verification, and monitoring low-level formaldehyde in coatings, adhesives and latex products.
Related standards
- ISO 2227 - Formaldehyde solutions for industrial use - Determination of formaldehyde content (referenced for standard assays).
- ISO 3696 - Water for analytical laboratory use - Specification and test methods.
Using ISO 15373:2024 helps laboratories implement reproducible, traceable methods for formaldehyde determination in polymer dispersions, improving product safety, regulatory conformance and analytical consistency.