Determination of salmon calcitonin in formulations by high-performance liquid chromatography with electrochemical detection

A novel HPLC method with electrochemical detection has been developed for the determination of salmon calcitonin (sCT). sCT was separated from other components in its formulations on a narrow-bore reversed-phase C-18 column with 33 % acetonitrile in 0.05 M phosphate buffer (pH 6.5) at a flow rate of 0.2 mL min(-1). Electrochemical oxidation of sCT at a glassy carbon electrode occurred at 0.87 V relative to the Ag/AgCl reference electrode. The limit of quantitation was 0.1 ng and the calibration curve was linear in the concentration range 0.5-20 ng; the correlation coefficient was 0.998. The method was successfully applied for the quantitation of sCT in commercial injection and nasal spray formulations.