This part of ISO 17226 specifies a method for the determination of free and released formaldehyde inleathers. This method is based on high performance liquid chromatography (HPLC). It is selective and notsensitive to coloured extracts.The formaldehyde content is taken to be the quantity of free-formaldehyde and formaldehyde extractedthrough hydrolysis contained in a water extract from the leather under standard conditions.