Full Description ADOPTED_FROM:EN ISO 17226-1:2019 This document specifies a method for the determination of free and released formaldehyde in leathers. This method, based on high performance liquid chromatography (HPLC), is selective and not sensitive to coloured extracts and is intended to be used for precise quantification of formaldehyde. The formaldehyde content is taken to be the quantity of free-formaldehyde and formaldehyde extracted through hydrolysis contained in a water extract from the leather under standard conditions.