Simultaneous determination of creatine and creatinine in the fish tissue extracts by high-performance liquid chromatography

Simultaneous determination of creatine and creatinine in the extracts prepared from fish tissues was objected by high-performance liquid chromatography (HPLC). The chromatography was carried out using a Wakosil-II 5C18 HG column and UV detector. Creatine and creatinine were eluted at 3.5 and 9.2 min, respectively, with 2 mM sodium dodecyl sulfate-10 mM KH2PO4/25% acetonitrile and at a flow rate of 1 ml/min. Creatine and creatinine in raw and heated muscles of alfonsin and saury and the raw muscle, liver, milt, and eggs of pejerrey were determined and compared with colorimetric assay methods previously reported. Creatine and creatinine amounting to 67-537 and 1-12 mg/100 g, respectively, were detected. Recoveries of creatine and creatinine added to the fish muscle was proven to be satisfactorily high by the HPLC ranging 95-101%. Creatine and creatinine in the cloudy extracts were also detectable in this HPLC.