Principles of Fluorescence Spectroscopy

878 APPENDIX I P CORRECTED EMISSION SPECTRA
Figure I.6. Chemical structure of fluorophores used as spectral standards.
Figure I.7. Corrected emission spectra in relative quanta per wavelength
interval (I(ν)). The quinine sulfate (QS) was in 0.1 N H 2SO 4.
3-aminophthalamide (3-APT) was in 0.1 N H 2 SO 4 . N,N-dimethylamino-m-nitrobenzene
(N,N-DMANB) was in 70% n-hexane, 30%
benzene. Modified from [4].
The data were not reported in numerical form. These corrected
emission spectra I(λ) were in agreement with that
reported earlier 6 in relative quanta per wavenumber (I(ν)),
following the appropriate transformation.
A more complete set of corrected spectra, 6,7 in I(ν) per
wavenumber interval, are summarized numerically in Figure
I.8 and Table I.7. These data contain an additional standard,
4-dimethylamino-4'-nitrostilbene (4,4'-DMANS),
which extends the wavelength range to 940 nm. These spectra
are plotted on the wavenumber scale in Figure I.8. For
Figure I.8. Corrected emission spectra in relative quanta per
wavenumber interval I(ν). See Table I.6 for additional details. Data
from [6] and [7].
convenience the data were transformed to the wavelength
scale, and are shown in Figure I.9 and Table I.8. In summarizing
these corrected spectra we omitted β-naphthol,
whose emission spectrum depends on pH and buffer concentration.
Because these factors change its spectral shape,
naphthol is not a good standard.
5. ULTRAVIOLET STANDARDS
2-aminopyridine (Figure I.10) has been suggested as a standard
from 315 to 480 nm, 8,9 which covers most but not all
of the wavelengths needed for tryptophan fluorescence
Figure I.9. Corrected emission spectra in relative quanta per wavelength
interval I(λ). See Table I.5 for additional details. Data from [6]
and [7].