How ph affects aesculune fluorescence?
You should investigate several pH and study the effect of time on the fluorescence spectra. One cannot quote single values without mentioning the wavelengths of excitation and emission.
pH can alter the state of  ionization and it can also cause hydrolysis of the sugar unit.
You need to collect three different types of spectra at each pH, say from pH 2 to 12.
At each pH, first measure the absorption spectrum at those pH values. This is the easiest experiment. Do you see a difference in absorption spectra at different pH values? Note the trends.  If yes, pH is affecting either the structure (decomposing) or the state of ionization.
Next, collect the excitation spectrum at a fixed emission wavelength (you have to estimate that). The excitation spectra should look similar to the absorption spectrum in shape.
Once you know the correct excitation wavelength at each pH, collect proper emission spectrum by using the lamba max of excitation.
So the answer is that be ready to see the changes in fluorescence spectra since there is no &quot;the&quot; fluorescence spectrum of a given molecule in a solution. You have to specify the solvent, pH, and excitation wavelength for experimental measurements.