INVESTIGATION OF THE QUENCHING OF PEROXYOXALATE CHEMILUMINESCENCE BY AMINE SUBSTITUTED COMPOUNDS

The role of amine compounds in quenched peroxyoxalate chemiluminescence was investigated. The mechanistic steps examined included (1) fluorescence quenching; (2) base hydrolysis of the oxalate; and (3) a competitive interaction between the quencher and fluorophore for the peroxyoxalate reaction intermediate(s). The results showed no evidence of amines causing fluorescence quenching. Base hydrolysis of the oxalate is significant only at high concentrations of amines. When the concentration of amines is greater than or equal to the level of oxalate, the amines can compete with the fluorophore for reaction with the intermediate(s). Because competitive effects were demonstrated, one analytical implication is that caution must be exercised in applications where more than one fluorophore is present. At low concentrations of fluorophores relative to the oxalate, chemiluminescence emission of both fluorophores will be observed. At higher levels, the fluorophores can compete for reaction with the intermediate(s). Finally, an important analytical implication of this study is that the quenching response can be used to quantify amines without the need for derivatization. The limitation is that the linear response is approximately one order of magnitude.