I am trying to measure the fluorescence spectra of pyrene molecules at excitation wavelength of 310 nm with emission scanning wavelength 350-450nm. But, getting broad spectrum instead of two or three peaks, essential for the calculation of I1/I3 ratio of self-assembly. Also tried the same using different sources of pyrene, but getting the same broad spectrum.
Herewith, attached the recorded spectrum.Please find it and provide suggestions.
Thanks,,
you need to use a higher end fluorimeter to have better resolution of your signals.
Your spectrum is very different from the actual spectrum in ethanol. You write about this yourself. It can be from a dirty pyrene. I recommend to clean it with zone melting (cleaning) in a glass ampoule. I used this device when I was in graduate school. A "dirty" pyrene is placed in a small ampoule with an internal diameter of 5 mm and a length of 15 cm. The ampoule is placed in the middle of several rings from the nichrome of the vertical furnace. The ampoule weighs on a metal thread on the shaft of the reducer with an electric motor. The ampoule moves at a speed of 10 mmh. Pyrene gradually melts and crystallizes. Impurities are shifted to the top and bottom of the ampoule. For the study, take the middle part of pyrene with a melting point of 150 ° C.
Ethanol, too, must be purified or used spectrally pure ethanol.
Dear Yuri,
Thanks a lot for valuable suggestion. I have purchased the pyrene from sigma-aldrich. Also tried the analysis using pyrene from different source. Not only ethanol, in DMSO as solvent, also found similar broad spectrum.
Could please let me know what is conc of pyrene solution you are using
Thanks for your response. I resolved the problem. The pyrene conc. is 1*10-6 M.
okay.. Good to know that.I am doing some experiments with pyrene. I used methanol as the solvent and concentration in micro molar range. I was able to get the spectrum.@ Nilkamal Pramanik
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