The application of our development of 750 nm excitation from an argon-hydrogen filled spark source to time-resolved fluorescence probe studies of lipid membranes and inverse micelles is reported. The laser dye IR-140 was studied using the single- photon counting technique both in a lipid membrane of L-$alpha dipalmitoylphosphatidylcholine (DPPC) and in sodium sulfosuccinic acid bis (2-ethylhexyl) ester (AOT) in iso-octane. In DPPC a dramatic change in the fluorescence behavior of IR-140 is observed between the gel and liquid crystalline phases. In inverse micelles of AOT an increase in the intensity of the peak fluorescence emission and a decrease in fluorescence lifetime is noticed on increasing the water content.
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