We have isolated a red pigment producing bacteria. We harvested the crude pigment by removing the cells by centrifugation. We tried to find the absorption maxima (lambda max) of the pigment using UV-VIs spectrophotometer. There were multiple peaks (around 30) in the 200-300nm region but no peak was found in the visible region.
We tried lyophilizing the solution to remove water content and dissolve it in other solvents like Methanol, DMSO to identify it by GC-MS / FTIR / LC-MS. In DMSO it solubilizes and settles down later. It is not soluble in any other solvent than water
Kindly suggest any protocols for purification an quantification of the pigment.
UV-Vis spectrum files are attached
Dear Karl J Samuel , I agree with Noel W Davies , your two UV-Vis spectra are saturated in the UV region. This is the reason you cannot see properly the absorbance of the visible region, but it is clearly there, like a broad shoulder.
If you can see a color for your sample, say red, it is generally (*) because the sample is adsorbing, so you should have an absorbance band there in the red region.
* (There are exceptions like structural colors, but probably they are not applicable to your sample).
Noel´s advice is right, you should repeat the experiment with much more dilute sample. Absortion in the UV region is very high, and it could mask the Vis region, so my advice is to select the range in the spectrometer to avoid the high UV absorption and therefore obtain a better spectrum in the Vis part.
Hope it helps.
There is definitely something around 400 and 600 nm, but because of the high absorption in UV area you cant see.
you can either:
- get the date from the spectrometer and trace from 360 to 800
or
- Try another UV-vis survey with same concentration from 360 to 800
alternatively, you can do exactly as suggested above by: Manuel Gómez and Noel W Davies
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