Detection of a distance-dependent rate of quenching by frequency-domain fluorometry

Jozef Kusba, Ignacy Gryczynski, Henryk Szmacinski, Michael L. Johnson, Joseph R. Lakowicz

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations


The effect of the collisional quenching on the fluorescence intensity decays has been studied by frequency-domain fluorometry. We used an efficient (CBr4) and/or inefficient (CCl 4 quencher to quench the fluorescence of 1,2-benzanthracene (1,2-BA). The wide range of diffusion has been obtained by using propylene glycol at different temperatures (-40°C to 40°C). The measured intensity decays cannot be satisfactorily fitted either to the Smoluchowski or Collins-Kimball (RBC) model, except the case of inefficient quencher in the presence of high diffusion. In particular, we observed quenching in diffusionless conditions (-40°C). To describe the collisional quenching of the fluorescence more correctly we propose a new model which includes a distance-dependent quenching rate (DDQ model). The DDQ simulations show that the local concentration of quencher surrounding the excited fluorophore cannot be approximated by using the RBC model, except in the case of high diffusion and low quenching rate. The DDQ model describes well all measured intensity decays of 1,2-benzanthracene in the presence of CBr4 and/or CCl4. Also, the DDQ model more correctly predicts the curvature of Stern-Volmer plots and activation energies obtained from the temperature dependent rate of quenching.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherPubl by Int Soc for Optical Engineering
Number of pages12
ISBN (Print)0819407860
StatePublished - 1992
EventTime-Resolved Laser Spectroscopy in Biochemistry III - Los Angeles, CA, USA
Duration: 20 Jan 199222 Jan 1992

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherTime-Resolved Laser Spectroscopy in Biochemistry III
CityLos Angeles, CA, USA


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