Fluorometric determination of streptomycin in serum by high-performance liquid chromatography using mobile phase...

A new postcolumn derivatization method for the fluorometric determination of streptomycin in serum by high-performance liquid chromatography is described. The serum was treated with 3.5% perchloric acid to precipitate proteins and the supernatant was directly injected into the chromatograph. Streptomycin was separated by reversed-phase, ion-pair chromatography with a mobile phase containing ninhydrin as a fluorogenic reagent, octanesulfonate, and 1,2-ethanedisulfonate as counterions, and was detected by fluorescence using continuous-flow, postcolumn derivatization in an alkaline stream with ninhydrin in the mobile phase. This method is sensitive to 1.0 microgram/ml using only 100 microliter of serum. Comparison with a fluorescence polarization immunoassay gave a good correlation coefficient of 0.976.