Fluorescence decay studies using multiplexed time-correlated single-photon counting: application to aminotetraphenylporphyrins

✍ Scribed by D.J.S. Birch; R.E. Imhof; C. Guo

• Book ID: 103991616
• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 601 KB
• Volume: 42
• Category: Article
• ISSN: 1010-6030
• DOI: 10.1016/1010-6030(88)80065-0

✦ Synopsis

We report fluorescence decay measurements tetraphenylporphyrins at fluorescence wavelengths _ of p-amino-substituted up to 680 nm using a fluorometer incorporating multiplexed single-photon timing detection channels for simultaneous acquisition of the fluorescence and excitation. This wavelength is the longest at which such differential measurements have hitherto been perfqrmed and the results agree closely with those obtained on the same instrument operated in the conventional manner using a single detection channel. SmaLl changes in the fluorescence decay time of about 1% are resolved, showing that the wavelength dependence of the instrumental pulse response is insignificant on these timescales. The porphyrins studied exhibit a subtle but ,discemible photophysical trend, whereby the addition of amino groups .reduces the fluorescence decay time as compared with that of the unsubstituted tetraphenylporphyrin in a manner which depends on the change in symmetry_