Electrogenerated chemiluminescence detection in reversed-phase liquid chromatography

Electrogenerated chemiluminescence (ECL) has been developed as a detection method for liquid chromatography. The radical cation of tri-p-tolylamine (TPTA) is used as a common electron acceptor for the electrogenerated radical anions of a variety of organic analytes. ECL is accomplished with a high-frequency potential pulse program applied to a microelectrode immersed in the column eluent. ECL detection is demonstrated with reversed-phase liquid chromatography. Selectivity at the ECL detector is shown to be tunable based on differing electrochemical conditions and excited-state energetics. Low minimum detection limits in ECL are attributed to the dependence on the photon detector shot noise, allowing a limit of detection of 0.14 nM for perylene in the presence of 0.1 mM TPTA. A derivatization agent useful for ECL detection is demonstrated by the use of naphthalene-2,3-dicarboxaldehyde. This reagent, which does not itself result in ECL, forms ECL candidates following reaction with primary amines.