REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF SALMON-CALCITONIN AND ITS DEGRADATION PRODUCTS IN BIOLOGICAL SAMPLES USING COLUMN-SWITCHING AND FLOW-THROUGH RADIOISOTOPE DETECTION

For the determination of salmon calcitonin and its degradation products in biological samples, a reversed-phase HPLC method with column switching and flow-through radioisotope detection has been developed using high specific activity [I-125]salmon calcitonin. Effects of the precolumn packing material and washing solvent were examined in terms of [I-125]salmon calcitonin recovery, Spiked samples of [I-125]salmon calcitonin in plasma and kidney homogenate were injected onto a LiChroprep RP-8 precolumn after dilution with 0.1% trifluoroacetic acid. After washing the polar interfering compounds with 0.1% trifluoroacetic acid, the concentrated [I-125]salmon calcitonin and its degradation products were eluted and separated on a W-Porex C-18 column with a gradient of 0.1% trifluoroacetic acid in acetonitrile-water. Detection and calibration of [I-125]salmon calcitonin were possible down to picogram levels. Reproducible kinetic data for the degradation of intact [I-125]salmon calcitonin by rat kidney homogenate could be traced.