A HIGHLY SENSITIVE CAPILLARY ELECTROPHORESIS LASER-INDUCED FLUORESCENCE DETECTION METHOD TO MEASURE ZEPTOMOLE AMOUNTS OF BRADYKININ

Capillary electrophoresis with laser induced fluorescence detection was used to measure bradykinine labelled by fluorescein isothiocyanate FITC (FITC-bradykinine), a derivatized compound obtained from bradykinine, an inflammatory peptide. Concentrations as low as 6.3 10(-13) M were derivatized to obtain a 1.9 10(-14) M solution and 4 nl were injected into the column. For this concentration of FITC-bradykinine a signal-to-noise ratio of 6:1 was obtained. This corresponds to 46 molecules of FITC-bradykinine in the column. The potential of laser-induced fluorescence for measuring biologically active peptides in capillary columns is discussed.