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

A now injection electrochemiluminescent inhibition method has been develope d 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 5 x 10(-8) to 1 x 10(-5), 5 x 10(- 8) to 1 x 10(-5) and 1 x 10(-8) to 5 x 10(-5) mol l(-1) the detection limit of 1.2 x 10(-8), 2.1 x 10(-8) and 5.2 x 10(-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 sp ectrophotometric method or chemiluminescent method. The method has been suc cessfully applied to determine chlorogenic acid in cigarettes. The mechanis m of the inhibition effect was proposed. Catechol derivatives mostly react with the freshly electrogenerated oxygen species on the electrode surface a nd lead to the inhibition of electrochemiluminescence. (C) 2000 Elsevier Sc ience B.V. All rights reserved.