Fluorescence Characteristics of 8-O-Phosphoryl, -Sulfuryl, and -Carboxymethyl Derivatives of 8-Hydroxyquinoline and Its Application to Micro-determination of Cadmium and Zinc

Fluorescence characteristics of 8-quinolyl derivatives substituted with anionic dissociative group at the hydroxyl in 8-hydroxyquinoline were examined in relation to that of 8-methoxyquinoline. A remarkable effect of Cd (II) and Zn (II) on the increase in fluorescence intensity of both 8-quinolyl dihydrogen phosphate (8-QP) and 8-hydroxyquinoline carboxymethylate (8-HQCM) was observed. Fluorometric examinations of these compounds in the presence of Cd (II) or Zn (II) suggested a possible formation of the fluorescent chelate ; 8-QP-Cd (II) (1 : 1) and 8-HQCM-Zn (II) (1 : 1). Fluorometric determination of Cd (II) and Zn (II) was successfully achieved by measuring the increase in fluorescence intensity of 8-QP or 8-HQCM in the presence of these ions.