This European Standard specifies a high performance liquid chromatography (HPLC) method for the determination of the content of maduramicin in feeding stuffs and premixtures. The usual concentration of maduramicin in feedstuffs is 5 mg/kg, in premixtures 500 mg/kg. The limit of quantification is 2 mg/kg. The limit of detection is 0,5 mg/kg. NOTE A lower limit of quantification may be achievable but shall be validated by the user.