ISO 18218-1:2023

Overview

ISO 18218-1:2023 specifies a direct analytical method for the determination of ethoxylated alkylphenols (APEO) in leather - principally nonylphenol ethoxylates (NPEOn, 2 ≤ n ≤ 16) and octylphenol ethoxylates (OPEOn, 2 ≤ n ≤ 16). The method is optimized for screening a large number of leather samples and requires liquid chromatography (LC) coupled to a triple quadrupole mass spectrometer (MS/MS) with electrospray ionization (ESI). Extraction is performed with methanol in an ultrasonic bath, followed by filtration and direct LC‑MS/MS analysis.

Key Topics

• Scope and purpose: Direct detection and quantification of APEO in leather to support environmental and regulatory compliance (e.g., REACH / EU restrictions on NPEO).
• Sample extraction: Approximately 1 g leather extracted with 20 ml methanol at (60 ± 5) °C for (60 ± 5) min in an ultrasonic bath; aliquots filtered (e.g., 0.2 µm) before LC analysis.
• Instrumentation: High‑performance LC with gradient elution and triple quadrupole MS/MS (ESI) for high selectivity and sensitivity-suitable for congener profiling (EO chain lengths 2–16).
• Standards & calibration: Use of stock (250 µg/ml) and standard solutions (25 µg/ml) with calibration examples spanning 0.5–2.5 µg/ml; quantification covers individual APEO congeners and total APEO content.
• Analytical details: Annex A provides example chromatographic conditions; Annex B lists characteristic masses for quantification. Method expects similar trends but not identical absolute values compared with ISO 18218‑2 due to different extraction solvents.
• Quality considerations: Use LC‑MS/MS grade methanol, traceable reference materials (commercial NPEO/OPEO technical grades cited), and ISO sampling/preparation practices (ISO 2418, ISO 4044, ISO 3696 referenced).

Applications

• Leather manufacturers and tanneries: Routine screening of incoming chemicals and finished leathers for APEO content to meet supply‑chain and product restrictions.
• Analytical and contract testing laboratories: High‑throughput testing using LC‑MS/MS for congener‑specific quantification of NPEO and OPEO.
• Regulatory compliance & auditing: Demonstrating conformity with environmental regulations restricting APEO/NPEO releases (REACH, EU directives).
• Sustainability and product safety teams: Monitoring surfactant residues that can biodegrade to endocrine‑active alkylphenols.

Related standards

• ISO 18218-2 - Indirect method for alkylphenol analysis (cleavage to alkylphenols).
• ISO 2418 - Specimen position and preparation for leather testing.
• ISO 4044 - Preparation of chemical test samples (leather).
• ISO 3696 - Laboratory water specification.

Keywords: ISO 18218-1:2023, leather testing, APEO determination, ethoxylated alkylphenols, NPEO, OPEO, LC‑MS/MS, methanol extraction, triple quadrupole mass spectrometer, nonylphenol ethoxylate.