ABSTRACT
FAC has been successfully used to derivatize primary and secondary amines [139]. Derivatives are optimally detected at +0.60 V vs. Ag/AgCl, and the oneelectron oxidation is reversible. Ferrocenecarboxylic acid (FCA), an electroactive hydrolysis product of FAC, is a potential chromatographic interference. Fortunately, being somewhat hydrophilic in nature, FCA elutes before the majority of analytes in reverse-phase HPLC. The FAC derivatives studied are extremely stable, with identical chromatograms obtained for samples analyzed one week apart when stored at 5°C. This derivatization technique may be used to monitor the enzymatic hydrolysis of 200 nmol of Gly-Phe-Leu. Using FAC, a substance P fragment that has proline at the N-terminus and therefore cannot be tagged with either OPA or NDA was successfully detected with detection limits in the 500 fmol (25 nM) range [139].
