ISO 11936:2023

Overview

ISO 11936:2023 specifies a laboratory method for determining the total solvent-extractible content of certain bisphenols in leather - specifically bisphenol A (BPA), bisphenol B, bisphenol F and bisphenol S. The procedure uses liquid chromatography (LC) coupled with detectors such as single-quadrupole MS, triple-quadrupole MS/MS, UV, diode array (DAD) or fluorescence (FLD) to identify and quantify bisphenols. The method is applicable to other bisphenols after laboratory validation and reports results in mg/kg.

Key topics and technical requirements

• Scope: Measurement of solvent-extractible bisphenols in leather samples (total content).
• Extraction: Ultrasonic methanol extraction - typical example: 0.5 g leather + 10 mL methanol, 60 min at 60 ± 5 °C, followed by filtration.
• Instrumental analysis: LC with MS/MS, MS, LC-UV, LC-DAD or LC-FLD. Annexes provide example chromatographic parameters for each technique.
• Calibration & internal standards: Calibration solutions from mixed bisphenol stock standards; internal, mass-labelled standards (recommended for LC-MS/MS or LC-MS) to reduce matrix effects.
• Quantification: Calculation formulas provided for with/without internal standard; results can be expressed as individual bisphenol mass fractions or as a summed result. Values below method thresholds are treated as zero according to detector type.
• Performance: Typical limits of quantification (LoQ) achievable - below 10 mg/kg with LC-MS/MS and around 100 mg/kg with LC-UV/DAD/FLD.
• Reporting: Test report must reference ISO 11936:2023 and include sample description, date, LC equipment used, quantified mass fractions (mg/kg), any deviations and unusual observations.

Applications

• Regulatory compliance and product safety: Verify leather products meet safety limits for bisphenol residues.
• Quality control and supplier verification: Monitor raw materials and finished leather for bisphenol contamination from tanning agents or monomer residues.
• Environmental and health risk assessment: Support studies on exposure pathways where bisphenols are of concern (e.g., BPA as an endocrine disruptor).
• Research and forensic testing: Analytical labs evaluating bisphenol occurrence in leather goods.

Who should use this standard?

• Leather manufacturers, tanneries and chemical suppliers
• Accredited testing laboratories performing chemical analyses on leather
• Regulatory agencies, product safety and compliance teams
• Environmental and materials scientists studying bisphenol residues

Related standards

• ISO 2418 - specimen position and preparation for leather testing
• ISO 4044 - preparation of chemical test samples (leather)
• ISO 3696 - water for analytical laboratory use

This concise, ISO-aligned method description helps laboratories and industry stakeholders implement reproducible LC-based analysis for bisphenol A, B, F and S in leather in accordance with ISO 11936:2023.