Fluorescence peak maxima

Fluorescence emission maximum Fluorescence quantum yield Molar absorption coefficient (e) at peak wavelengths (as monomer)... 

The bioluminescence spectrum of P. stipticus and the fluorescence and chemiluminescence spectra of PM are shown in Fig. 9.7. The fluorescence emission maximum of PM-2 (525 nm) is very close to the bioluminescence emission maximum (530 nm), but the chemiluminescence emission maximum in the presence of a cationic surfactant CTAB (480 nm) differs significantly. However, upon replacing the CTAB with the zwitter-ionic surfactant SB3-12 (3-dodecyldimethylammonio-propanesulfonate), the chemiluminescence spectrum splits into two peaks, 493 nm and 530 nm, of which the latter peak coincides with the emission maximum of the bioluminescence. When PM-1 is heated at 90°C for 3 hr in water containing 10% methanol, about 50% of PM-1 is converted to a new compound that can be isolated by HPLC the chemiluminescence spectrum of this compound in the presence of SB3-12 (curve 5, Fig. 9.7) is practically identical with the bioluminescence spectrum. 

Fluorescence. Upon excitation at 370 nm, the emission spectrum from the digests of glucose-exposed dentin slices showed a broad peak (maximum 420 nm), which was strongly increased compared with the background peak in buffer-exposed dentin. This background peak was no contamination of buffer salts, since it was also present in demineralized water. The broad peak at 420 nm also overlapped a broad shoulder peak at 480 nm that occurred in the buffer-exposed dentin (fig. 2). The 370/440 nm fluorescence of glucose-exposed dentin slices was significantly increased compared with controls (table 2). 

The effusate which condensed on liquid nitrogen cooled copper collection targets was assayed by X-ray fluorescence. The Eu La radiation was determined at the peak maximum (26 = 36.84°, graphite analyzing crystal) by an external standard technique. Previous data (15, 19) have indicated the sticking coefficient of gaseous europium halide on chilled copper is approximately unity. 

In 1966, Walker, Bednar, and Lumry postulated the formation of a 1 2 excited complex state in the system indole-pentane- butanol [101]. Two years later, Beens and Weller found fluorescence emission at 475 nm from an excited complex composed of two molecules of naphthalene and one of 1,4-dicyanobenzene. They postulated the unsymmetrical structure (DD+ A- ) from the solvent dependence of the wavelength of the peak maximum (high dipole moment in contrast to DAD structure) [102]. Later, several other groups detected such termolecular species. For a review on earlier contributions, see Ref. [103]. 

The fluorescence emission maximum of CGTase is located at 338 nm, and its spectrum bandwidth is 55 nm (Figure 7.12a). Thus, both embedded and surface tryptophan residues contribute to protein fluorescence. Although CGTase contains many tyrosine residues, the absence of a shoulder or a peak at 303 nm (Figure 7.12b), when excitation is performed at 273 nm, suggests that tyrosine residues do not contribute to CGTase emission. 

We point out that another partial explanation for the experimentally observed red-shift is the combination of excitation and emission factors that enter the total enhancement expression. Since a fluorophore s fluorescence peak is red-shifted from its absorption peak, it is likely that the point of maximum brightness will also require some compromise between excitation and emission enhancement. This explanation has been given by Rothberg for fluorescence enhancements from random Ag colloidal films and is reminiscent of the optimum position of the LSPR... 

Fig. 6. QAPB (BODIPY FL-prazosin, 5 nM) binding to neuronal cells on the surface of a section of rat anococcygeus (A) xy view of fluorescence at time-point zero, before addition of rauwolscine (B) intensity profile plot of image a showing varying fluorescence intensity as peaks (C) 2 min after addition of rauwolscine (30 pM), the height of the peaks is reduced (D) after 12 min, the maximum reduction in fluorescence (peak height) is achieved. The two rectangular areas shown in A have their respective fluorescence intensity measured and plotted over time (see inset) to show the development of fluorescence intensity reduction.

Recently, chromophore 56 was the subject of TPA studies (Table 3.6) [370]. The TPA cross section is smaller in comparison to that of 53-55 although 8 for 56 was not taken at the peak maximum of the TPA spectrum. The maximum for TPA is far away from the data reported [370]. Data obtained are larger compared with 43b, which was extensively investigated in TPA studies. This shows again that dipolar ionic chromophores are more appropriate for TPA applications because of the larger <5. The fluorescence quantum yield is also low and comparable with that of 56. 

Fig. 12 (A) shows fluorescence spectra of phycobilisomes recorded at different times after excitation. Initially a small emission band at 620 nm and a major band at 640 nm appeared, the latter shifting to 645 nm with time. The 645-nm emission due to PC reaches the maximum intensity at 40ps, while the fluorescence peak near 660 nm from APC begins to appear at 50ps. This 660-nm band shifts to 665 nm with time and reaches a maximum intensity at 200ps, and then decays rapidly after that. Concomitant with the decay of the 665-nm emission is a rise of a 685-nm emission from the terminal emitter. At -1 ns (see the 932-ps spectrum), the 645- and 665-nm bands have almost entirely decayed, and only the 685-nm band remains. These results are consistent with a sequential transfer of excitation energy from the rod to the core, i.e., PC -> APC —> terminal emitter.

Schwertner has isolated albumin-associated fluorescent ligands that have an emission maximum of 415 nm (S17). The fluorescent species is very water soluble and can be removed by charcoal (S16). A positive correlation was found between fluorescence and serum creatinine in patients maintained on conservative treatment (D15), but not in patients already on hemodialysis (S16). Interestingly, the serum of patients with acute renal failure does not emit this fluorescence, a fact that has been proposed as a differential criterion between acute and chronic renal failure (V2). Mabuchi et al. have used HPLC to demonstrate numerous endogenous fluorescent substances at excitation (Ex) 322 nm/emission (Em) 415 nm in chronic renal failure and concluded that some of these fluorescent peaks probably represented peptidic substances, but did not identify any of them (M7). 

Features of fluorescence spectra. The excitation and emission fluorescence spectra of Tb3+, Tb-DNA, Tb-RNA, Tb3+-PCA, Tb3+-PCA-RNA, Tb3+-PCA-DNA are shown in Fig. 1(a) and (b). No characteristic fluorescence of Tb3+ was observed in Tb3+. Tb-DNA and Tb-RNA systems, but Tb3+-PCA system emits three strong characteristic fluorescence peaks of Tb3+ located at 489 nm, 546 nm and 587 nm, which correspond to the 5D4-7F6, 5D4-7F5 and 5D4-7F4 transitions of Tb3+, respectively. The maximum excitation wavelength was 320 nm. The fluorescence intensity of the Tb3+-PCA system was strongly quenched with the addition of nucleic acids. However, the quenching fluorescence intensity of RNA is much stronger than that of DNA. We chose a peak of excitation wavelength 320 nm, and... 

Hexavalent uranium fluoresces brilliant green, peaking between 500 and 540 nm in most glass hosts. The brilliance of uranium fluorescence far exceeds that of the most efficient organic dyes. The fluorescence emission spectrum of hexavalent uranium-doped silica gel-glass is presented in Fig. 7. The peak maximum is at 533 nm [35]. 

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