title: New fluorescent labels: 4- and 7-chlorofluorescein.
abstract: A new mixture of 4- and 7-chlorofluorescein were synthesized by condensation of resorcinol with 3-chlorophthalic anhydride in the presence of methanesulfonic acid or zinc chloride. These regioisomers were successfully separated by chromatography. The photophysical properties were examined and their absorption and emission maxima at long wavelength, high fluorescence quantum yield, and narrow emission bandwidth were found, highly favorable for detecting multiple target substances in the same sample. Furthermore, 4(7)-chlorofluorescein was found to be strongly pH-dependent between 4.0 and 8.0, and could be used as pH-sensitive fluorescent probe to measure intracellular pH.
authors.affiliation: School of Pharmaceuticals and Biotechnology, Tianjin University, Tianjin, 300072, PR China.
authors.forename: Feng-Yan
authors.initials: FY
authors.lastname: Ge
authors.forename: Xi-Long
authors.initials: XL
authors.lastname: Yan
authors.forename: Fan-Yong
authors.initials: FY
authors.lastname: Yan
authors.forename: Hui-Ying
authors.initials: HY
authors.lastname: Pan
authors.forename: Li-Gong
authors.initials: LG
authors.lastname: Chen
mesh_terms: D005452:Fluoresceins / Q000138:chemical synthesis / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration
chemical_list: C510158:4-chlorofluorescein; C510159:7-chlorofluorescein; D005452:Fluoresceins; D005456:Fluorescent Dyes