This European Standard specifies a procedure for the determination of the content of free fatty acid, FFA, in alkylamidopropylbetaines, which is defined as being the amount of fatty acid expressed in grams per 100 g of product. This method has been validated for the determination of fatty acids from C6 to C20 in a total concentration range from 0,02 g to more than 3,0 g fatty acid per 100 g of product.