Determination of some catechol derivatives by a flow injection electrochemiluminescent inhibition method.

A flow injection electrochemiluminescent inhibition method has been developed for the determination of some catechol derivatives based on studying the inhibition phenomena of these compounds to the electrochemiluminescence of luminol. The linear calibration range of 5x10(-8) to 1x10(-5), 5x10(-8) to 1x10(-5) and 1x10(-8) to 5x10(-5) mol l(-1(,)) the detection limit of 1.2x10(-8), 2.1x10(-8) and 5.2x10(-9) mol l(-1)were obtained for catechol, 3,4-dihydroxybenzoic acid and chlorogenic acid, respectively. The method has higher sensitivity and wider dynamic range than conventional spectrophotometric method or chemiluminescent method. The method has been successfully applied to determine chlorogenic acid in cigarettes. The mechanism of the inhibition effect was proposed. Catechol derivatives mostly react with the freshly electrogenerated oxygen species on the electrode surface and lead to the inhibition of electrochemiluminescence.