Analytical Method
Chemical quantification of ethoxylated alkylphenols in leather products uses liquid chromatography combined with mass spectrometry detection. ISO 18218-1 specifies a standardized test procedure for extracting and measuring nonylphenol ethoxylates and octylphenol ethoxylates in leather substrates. Surfactants containing alkylphenol ethoxylates pollute aquatic ecosystems when released from processing tanneries into wastewater streams.
International regulations enforce strict concentration limits on these restricted substances to prevent environmental contamination.
Extraction Protocol
Leather samples are chopped into small pieces and extracted with methanol using ultrasound assistance at elevated temperature. The liquid extract undergoes filtering to remove particulate matter before injection into the high-performance liquid chromatograph. Solvents dissolve target surfactant molecules while leaving insoluble leather proteins behind in the sample vessel.
Standardized solvent volumes and extraction durations ensure consistent analytical recovery across commercial laboratories.
Solvent Separation
Chromatographic separation isolates individual ethoxylate chain lengths based on polarity and molecular mass. Mass spectrometer detectors quantify specific mass-to-charge ratios, identifying targeted chemical compounds at microgram levels. Calibration curves constructed with certified reference materials establish exact concentrations in milligrams per kilogram of leather.
Compliance Requirement
Global apparel brands require certified laboratory reports confirming compliance with ISO 18218-1 limits before approving leather shipments. Tanneries must audit chemical suppliers to eliminate restricted alkylphenol surfactants from fatliquoring and processing formulations.
