Problems with Raman Spectroscopy

[GuiHn]

Hello,

Recently I had a problem in the analysis of a raw material called Propranolol HCl, when performing Raman identification for the specific batch the obtained spectrum does not generate signal and, consequently, identity of the material.

By testing other techniques like infrared and NMR, I got the results without problems.

It turns out that I need to understand why the problem occurs only in Raman spectroscopy. Searching the internet did not find anything that could explain, since the problem happens only with this lot in question, other lots of the same product provide perfect spectra.

Anyone who has good knowledge of the technique could help me?

Thank you.

 

[DrClaude]

I'm far from an expert in the field, but my first intuition is to test the Raman spectrometer. Have you tried producing other spectra, such as for ethanol or acetone, which you probably have in your lab?

 

[GuiHn]

I'm far from an expert in the field, but my first intuition is to test the Raman spectrometer. Have you tried producing other spectra, such as for ethanol or acetone, which you probably have in your lab?

Hello, thanks for the help. In the laboratory we have a polystyrene standard that is made before any reading to evaluate the equipment. In addition, in the same equipment we made other batchs of the same product that had the spectra with normal intensity, only for this batch that we did not obtain spectra with product identity.
Initially I imagined that it could be a physical characteristic of the batch, but the granulometry and other aspects are similar with the other batchs that approved in the identification

 

[HAYAO]

That's strange. What wavelength is the laser?

 

[GuiHn]

That's strange. What wavelength is the laser?

Hello, the wavelength is the standart of equipament 785nm, I can't change this value.
I've been thinking that this raw material has a smaller fluorescence signal, but I don't have the equipment to prove it.

 

[Mien_J]

Some material have low raman intensivity. Do you have big thickness this material ? Do you have long exposition? Can you growing optical power up or wide slit?