Chemiluminescent detection of chlorophenols with a fiber optic sensor

A new method for the chemiluminescent detection of halophenols is presented. It is based on the ability of certain substituted phenols to enhance the chemiluminescence reaction of luminol catalyzed by horseradish peroxidase. The magnitude of enhancement depends on the particular enhancer employed and also on the enhancement concentration. Taking advantage of the properties of these enhancers, a flow injection analysis (FIA) method for halophenols involving a fiber optic sensor and immobilized peroxidase has been developed. We mainly focussed on the detection of chlorophenols due to their toxicity and persistence in the environment. The composition of the reaction medium have been optimized. Among the ten chlorophenols tested, six of them could be determined with the present method with a detection limit varying from 0.5 mu M to 100 mu M. The greatest sensitivity was obtained for 4-chloro-3-methylphenol whereas for the others the sensitivity decreased according to the following order : 4-chlorophenol > 2,4-dichlorophenol > 2-chlorophenol = 3-chlorophenol > 2,4,5-trichlorophenol. Pentachlorophenol, 2,4,6-trichlorophenol, 2,6-dichlorophenol and 2-amino-4-chlorophenol could not be detected by this chemiluminescent method.