ISO 15181-4:2008

Overview

ISO 15181-4:2008 - Paints and varnishes - Determination of release rate of biocides from antifouling paints - Part 4 specifies a laboratory method to determine the concentration of pyridine‑triphenylborane (PTPB) in artificial seawater extracts and to calculate the PTPB release rate from antifouling paints. Used together with ISO 15181‑1 (general extraction), this ISO 15181-4:2008 method provides a repeatable laboratory release-rate value for quality assurance and material selection under controlled temperature, salinity and pH.

Key Topics and Requirements

• Analyte: Pyridine‑triphenylborane (PTPB) in artificial seawater extracts.
• Analytical principle: HPLC with UV detection at 220 nm after pre‑concentration by solid‑phase extraction (SPE), or another method with equivalent sensitivity.
• Sample preparation: Add pyridine to 1% v/v, pass 100 ml through a pre‑conditioned C‑18 SPE cartridge (360 mg sorbent), wash and elute; final eluate adjusted to 20 ml. Optional concentration step (rotary evaporation + N2 drying) allows lower limits of quantitation.
• Chromatography essentials: Reverse‑phase C‑18 column (4.6 mm × 250 mm, ~5 µm), isocratic eluent (acetonitrile/water/TBAP ion‑pair reagent), autosampler (10 µl injections), column oven at 30 °C.
• Limits and performance: The method targets a limit of quantitation (LOQ) for PTPB in artificial seawater of ≤10 µg/L; with additional concentration the LOQ can reach ~0.5 µg/L. Practical measurable release‑rate range when used with ISO 15181‑1: 1.8 to 500 µg·cm⁻²·d⁻¹.
• Quality controls: Triplicate determinations, calibration using PTPB standards (50–1 000 µg/L range), instrument blank checks and linear regression calibration.

Applications and Who Uses It

• Paint manufacturers and R&D teams: evaluate antifouling formulations and adjust biocide content.
• Independent testing laboratories: provide standardized release‑rate data for product specifications and batch quality control.
• Coatings formulators and material selection specialists: compare biocide leaching behaviour under standardized lab conditions.
• Regulatory or advisory bodies (for lab-based comparisons only): note that ISO 15181‑4 results are not direct environmental release rates and typically overestimate in‑service releases; apply correction factors if used in environmental assessments.

Related Standards

• ISO 15181‑1:2007 - General method for extraction of biocides (required for sample generation).
• Other parts of ISO 15181: Part 2 (copper), Part 3 (zineb/ETU), Part 5 (tolylfluanid/dichlofluanid analyses).
• ISO 3696 (water for analytical use) and ASTM D6442 (copper release method) referenced for performance checks.

Keywords: ISO 15181-4:2008, PTPB, antifouling paints, biocide release rate, HPLC, solid‑phase extraction, artificial seawater, limit of quantitation, testing standard.