ChemistryForever - 9-12-2018 at 08:42
Since IR spectrometers and NMR ones are very expensive, i think that a good option to verify the purity of some synthesized chemicals would be an
UV-vis spectrophotometer as it is cheaper. The problem is that without the spectra of the pure product is hard to say if you got the compound or not,
or at least i have not studied uv spectrophotometry. Where can I find a website where i can type a compound and i can find its spectra, so that i can
match them to see if i got the compound?
unionised - 9-12-2018 at 09:32
UV libraries exist but they are less common than IR ones.
Part of the problem is that the UV spectrum depends on solvent.
Also UV spectra are more susceptible to the effects of impurities.
(Think how many chemicals that should be clear are usually yellowish or some such)
From a point of view of proving purity, that's good, but it makes it difficult to interpret a spectrum. Does it not match because it's the wrong
stuff, or because it's only 99% pure?
Also, most UV spectra look pretty similar. A UV match isn't strong evidence of identity.
On the other hand, you can have a reasonable go at estimating UV spectra
https://en.wikipedia.org/wiki/Woodward%27s_rules