Overview
ISO 21264:2019 - Surface active agents - Detergents - Determination of alkylphenol ethoxylates (APEOs) - specifies an HPLC-based analytical method for the detection and quantification of alkylphenol ethoxylates (APEOs) in surfactants and detergents. The method uses high performance liquid chromatography (HPLC) with either a diode array detector (DAD) or fluorescence detector (FLD) and covers sample extraction, calibration, analysis and reporting to support reliable APEO measurement.
Key topics and technical requirements
- Scope and principle: Extraction of sample in methanol (ultrasonic bath), filtration and HPLC analysis with external calibration for quantification.
- Reagents & materials: HPLC-grade methanol; example standards include octylphenol ethoxylates (OPEO) and nonylphenol ethoxylates (NPEO).
- Apparatus: Analytical balance, ultrasonic bath, 0.45 µm membrane filter, volumetric flasks and HPLC (DAD or FLD) with a reverse-phase C18 column (example: 150 mm × 2.1 mm, 3.5 µm).
- Chromatographic conditions (example):
- Mobile phases: methanol / water gradient
- Flow rate: 0.3 ml/min
- Column temperature: 40 °C
- Injection volume: 10.0 µl
- Detection: DAD at 225 nm or FLD Ex 230 nm / Em 296 nm
- Calibration & limits: 5‑point calibration curve required (correlation coefficient R > 0.990 or R > 0.980 as noted). Reported LOQs: OPEO ~25 mg/kg and NPEO ~10 mg/kg (matrix and instrument dependent).
- Quantification & calculation: External calibration based on peak areas; the standard gives the formula to convert measured peak areas to mg/kg in sample, accounting for sample mass and extract volume.
- Quality control & precision: Method validation, matrix spikes/blanks, target recoveries ≥ 90%, and specified repeatability/reproducibility evaluation. Test reporting requirements are detailed.
Applications and who uses this standard
- Quality control laboratories in detergent and surfactant manufacturing
- Environmental and regulatory testing labs monitoring APEO content in products
- Research laboratories studying surfactant formulations and pollutant assessment
- Compliance teams validating product declarations against safety or regulatory limits
ISO 21264:2019 helps organizations implement a reproducible, traceable HPLC method to detect and quantify potentially ecotoxic APEOs in commercial surfactants and detergent matrices.
Related standards
- ISO 607 - Surface active agents and detergents - Methods of sample division (referenced for sample preparation and storage)
- Prepared by ISO/TC 91 (Surface active agents)
Keywords: ISO 21264, APEOs, alkylphenol ethoxylates, HPLC, DAD, FLD, detergents, surfactants, LOQ, calibration curve, sample extraction, method validation.