Fluorophotometric determination of sulfide ion and 8-hydroxyquinoline with 3, 4, 5, 6-tetrachloro-fluorescein mercury compound.

Abstract

An imporved method for the fluorophotometric determination of micro amounts of sulfide ion and 8-hydroxyquinoline were developed by using five halogenofluorescein mercury compounds as the reagents. The fluorescence intensities of silfide ionhalogenofluorescein mercury compounds and 8-hydroxyquinoline-halogenofluorescein mercury compounds were examined. Among them 3, 4, 5, 6-tetrachlorofluorescein mercury compound (T. Cl. Fl. Hg4) formeda very stable, pink colors with sulfide ion or 8-hydroxyquinoline in the presence of polyvinylpyrolidone, and a marked decrease in the fluorescence intensity of T. Cl. Fl. Hg4 solution accompanied with the color formation. Consequently, the fluorescence intensity of T. Cl. Fl. Hg4-sulfide ion or T. Cl. Fl. Hg4- 8-hydroxyquinoline complex was applied to a sensitive and simple fluorophotometric determination of minute amounts of sulfide ion and 8-hydroxyquinoline. Maximum difference of fluorescence intensity between T. Cl. Fl. Hg4 solution and T. Cl. Fl. Hg4-sulfide ion or T. Cl. Fl. Hg4-8-hydroxyquinoline solution was observed at 550nm, and the fluorescence intensities were constant in the pH range from 6.4 to 7.0 for determination of sulfide ion and from 8.8 to 9.5 for determination of 8-hydroxyquinoline by adjustment, respectively. The calibration curves were linear in the concentration range of 0 to 40μg/10ml for sulfide ion and 0 to 20μg/10ml for 8-hydroxyquinoline, respectively. The effects of diverse ions on the fluorophotometric determination of sulfide ion and 8-hydroxyquinoline were examined. Zinc (II), lead(II), bismuth(III) and copper(II) could be masked by addition of iminodiacetic acid or nitrilotriacetic acid soluiton, but thiocyanate ion, thiosulfate ions and ammonium ion must be avoided. The reaction is quite sensitive, and the procedure is simple.