Hi all,
I came across an odd result when analyzing a control sample of PNIPAm in different concentrations. They were around 1% and exhibited a strong fluorescence around 330 nm in a spectrofluoremeter, when exciting at 280 nm.
Over the literature PNIPAm is considered a non-fluorescent molecule, as per its structure, however I have tried this analysis a few times and it seems very consistent (different flasks and molecular weights). One possible hypothesis is the presence of a degradation product. Anyone had a similar experience with this material?
Thanks!
Try this: change the excitation wavelength by a small amount (say 5 nm) and see whether the emission peak shifts too. This would indicate that the apparent fluorescence you see is not coming from the substance, but is instead due to Raman scattering from the solvent. If the signal is actually due to fluorescence of the compound, the emission peak will not shift.
Thanks for your input Adam B Shapiro ! As I am using a EEM approach the sample is excited using different wavelengths and emission is captured too. The peak always happens at Exc280/Em337.
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