Ketahanan sampel urin terhadap waktu dan kondisi penyimpanan dalam penentuan kadar senyawa asam trans trans mukonat asam s fenil merkapturat asam hippurat asam 2 metil hippurat asam 3 metil hippurat serta asam 4 metil hippurat menggunakan instrument = Resistance of urine sample against storage time and condition for the determination of compounds tt ma spma ha 2 ha 3 mha and 4 mha by high performance liquid chromatography