title: Quantum counter for correcting fluorescence excitation spectra at 320- to 800-nm wavelengths.
abstract: A procedure for recording corrected fluorescence excitation spectra to wavelengths as long as 800 nm is described. The procedure involves the use of a commercial spectrofluorometer, which is modified by substituting 1,1',3,3,3',3'-hexamethylindotricarbocyanine perchlorate in place of rhodamine B as the quantum counter dye. This modification is applicable to spectrofluorometers supplied by several different manufacturers and can be accomplished by a user having only modest technical skills. A study of the fluorescence excitation spectrum of bacteriochlorophyll a is presented as an illustration of the use of the procedure. The procedure will be valuable in biological and biochemical studies that involve the use of long-wavelength fluorescent probes of either natural or synthetic origin.
mesh_terms: D001429:Bacteriochlorophylls / Q000032:analysis; D002232:Carbocyanines / Q000032:analysis; D005456:Fluorescent Dyes / Q000032:analysis; D012997:Solvents; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*
chemical_list: D001429:Bacteriochlorophylls; D002232:Carbocyanines; D005456:Fluorescent Dyes; D012997:Solvents; C053313:1,1',3,3,3',3'-hexamethylindotricarbocyanine