This International Standard defines a method for the determination of lipophilic substances of low volatility in water using gravimetry. The method is applicable to all kinds of water and allows the determination of low-volatility lipophilic substances which are suspended, emulsified, or dissolved, in concentrations of about 10 mg/l to 500 mg/l. Above this value, the test portion is diluted appropriately. The method is not applicable to water with a separate oil layer.