DEVELOPMENT OF A NOVEL CHEMILUMINESCENT PROBE, 4-(5',6'-DIMETHOXYBENZOTHIAZOLYL)PHTHALHYDRAZIDE

4-(5',6'-Dimethoxybenzothiazolyl)phthalhydrazide (DBPH) was synthesize d as a new, highly sensitive chemiluminescent reagent. The reagent con sists of phthalhydrazide and benzothiazole moieties and generates stro ng chemiluminescence by reaction with hydrogen peroxide in the presenc e of potassium hexacyanoferrate(III) or peroxidase. The chemiluminesce nce intensity of DBPH was about 20 times greater than that of luminol. The detection limit of DBPH was 1.3 x 10(-11) M [0.65 fmol per well ( 200 mu l), signal to blank ratio = 2]. The reaction of DBPH was also a pplied to the determination of hydrogen peroxide by flow injection. Th e detection limit is 0.5 pmol for a 100-mu l injection.