Steady-state f luorescence emission and f luorescencequenching
studies were performed in 0.31-cm quartz cuvettes.
Tryptophan was exited at 295 nm, and emission spectra were
recorded at 1-nm intervals between 310 and 450 nm by using an
integration time of 0.5 s. In all cases, polarizers were used in a
magic-angle position (54.7°) to correct for polarization effects on
intensity, reduce direct contribution of light scattering, and
eliminate polarization effects in monochromator transmittance
(38). Each spectrum is the average of two scans.