Overview
ISO/TS 13907:2012 - "Soil quality - Determination of nonylphenols (NP) and nonylphenol-mono- and diethoxylates - Method by gas chromatography with mass selective detection (GC‑MS)" - specifies a validated analytical procedure for measuring nonylphenol (NP), nonylphenol‑monoethoxylates (NP1EO) and nonylphenol‑diethoxylates (NP2EO) in sludge, treated biowaste and soil. The method uses extraction, optional clean‑up and concentration, chemical derivatization with MSTFA and analysis by GC‑MS with internal‑standard quantification. Achievable limits of detection are 0.1 mg/kg (sludge) and 0.02 mg/kg (soil and treated biowaste) expressed on a dry‑matter basis; lower LODs are possible by concentrating extracts.
Key topics and technical requirements
- Target analytes: NP, NP1EO, NP2EO (mixtures of isomers); method can also include 4‑tert‑octylphenol if required.
- Sample matrices: sludge (municipal sewage sludge validated), treated biowaste, soil.
- Extraction: shake extraction using acetone : petroleum ether (1:1) after sample pretreatment (freeze‑drying or other ISO pretreatment standards).
- Clean‑up & concentration: optional column clean‑up and solvent evaporation to improve detection limits.
- Derivatization: silylation using N‑methyl‑N‑(trimethylsilyl)‑trifluoroacetamide (MSTFA) in isooctane to make analytes GC‑amenable.
- Detection & quantification: gas chromatography with mass selective detection (GC‑MS), internal standard calibration using 13C‑labelled 4‑n‑NP and 13C‑labelled 4‑n‑NP2EO; identification based on retention times and diagnostic ion ratios.
- Interferences: address co‑eluting compounds and ion overlaps; exclude peaks that deviate in retention time or diagnostic‑ion ratios by >30% from calibration standards.
- Quality & storage: reagent grades, frozen storage of standards (≈ −18 °C), and stability guidance for calibration/internal standard solutions.
- Personnel & safety: testing requires suitably trained laboratory staff and standard laboratory safety practice.
Applications and users
- Environmental and soil‑quality laboratories performing routine monitoring of endocrine‑disrupting compounds in soils and biosolids.
- Wastewater and sludge testing labs assessing contamination from nonylphenol polyethoxylate (NPEO) degradation.
- Regulatory agencies and compliance testing for contaminant limits in biosolids, treated biowaste and soils.
- Research groups studying environmental fate and degradation of nonylphenols and their ethoxylates.
- Industrial producers and environmental consultants conducting impact assessments or source‑tracking of surfactant residues.
Related standards
Keywords: ISO/TS 13907:2012, nonylphenol, NP1EO, NP2EO, GC‑MS, soil quality, sludge analysis, MSTFA, derivatization, detection limit, environmental monitoring.