I am new to HPLC, and I am trying to devise a protocol to deal with poorly studied alkaloids (solenopsins). There is a variety of solvents which can dissolve these compounds, and I am trying to combine them for separation. However I keep having problems with the appropriate wavelengths for detection (my system does not have a dyode array).
A library containing .jpeg images of many compound spectra would come in very handy, and I was surprised that it is so hard to find. Does anyone have a hint?
I think it will be hard to find, maybe impossible. Some manufacturers (ie Waters) can provide a recognition library on DAD, but usually these files are not on standard files like jpeg or so but in files only readable on the dedicated software. Moreover poorly studied compounds will be ever harder to find.
Still I am amazed that there isnt a library of spectra of commonly used compounds, like acetone or methanol?
If you have a UV/VIS spectrophotometer you can first determines the sample's absorbance spectrum and then determine the wavelength of maximum absorbance.
There is no such library. However, I would recomend UV and IR Spectra Pharmaceutical Substances Dibbern Cantor 2002, Instrumental Data for Drug Analysis Mills Roberson 1993 and newer editions
For IR spectra and some UV as well try webbook.nist.gov , also try https://secure2.pnl.gov/nsd/nsd.nsf/Welcome for another source of IR spectra.
There is no meaning with any HPLC spectra of your compound though people use different instruments with different settings and solvent compositions and so on. What you should do is that you take a scan UV-VIS of your compound and find a proper peak that you can work with. Usually these kind of compounds should have a nice peak at Ultraviolet range of lights between 260-300 nm due to their ring structures. find that and then you are on go!
Siamak Shoravi
It sounds like what you are really looking for is the wavelength a solvent becomes unsuitable for use with UV. These are tabulated in many places, and in most column catalogs as cutoffs at 1AU. Methanol is 205 nm, acetonitrile is 190, and acetone is listed at 330. You should be able to scan a mobile phase with your detector.
Burdick & Jackson published a book with all solvent specifications used in HPLC. I expect it can be found online.
Hi, i suggest you NIST web book website to find physico-chemical property of millions of organic and inorganic compound especially their spectra such as uv-vis, IR, xrd, nmr, Mass and ... the web address was presented in following.
http://webbook.nist.gov/chemistry/
See the attachment. Are you sure that hplc is the best techniques? By the chemical structure of the solenopsins probabily the uv spectra will be poor resolution.
Hi! I like: http://sdbs.riodb.aist.go.jp/sdbs/cgi-bin/cre_index.cgi?lang=eng
Hi
You may try this link:
http://sdbs.riodb.aist.go.jp/sdbs/cgi-bin/cre_index.cgi?lang=eng
If alkaloids are known than use individual standards and determine spectra by UV spectrophotometer, but if you are getting unknown peaks you need to have PDA or isolate all by preparative HPLC and individually scan for UV spectra.
Hiii....
As all other experts have suggested i am completely agree to them.
Best thing is if you have an standard(marker) with you, make a solution of that scan solution in UV- Spectrophotometer find out maxima and accordingly select the same absorption maxima in HPLC detection.
If you don't have standard with you try to just figure of what is the basic ring present in structure of your compound of interest and try to find out information on the HPLC analysis of such drugs or compounds.
You can also refer, "Plant Drug Analysis by Hildebert H. Wagner, Sabine Bladt " it is color atlas chromatograms of herbal drugs. You can try to correlate your analyte with analytes given in that book and select that detection wavelength for detection in HPLC analysis.
Hope i have added some additional information and i shall be glad if it helps you by any means.
Thanks..
As recommended by some colleagues check this link
http://sdbs.riodb.aist.go.jp/sdbs/cgi-bin/cre_index.cgi?lang=eng
Also you can deterime the UV spectrs of these alkalods if you have standards for them using a solution of these compounds in the bobile phase you anticipate to use.
I am fully agree with Siamak Shoravi's answer, and acetonitrile will give you best results as far as solvent is concerned.
Use the Aldrich webpage. Another good one is sdbs, found at:
http://sdbs.riodb.aist.go.jp/sdbs/cgi-bin/cre_index.cgi?lang=eng
Aldrich has a good spectral collection and also spectral database for organic compounds is another good source.
Aldrich has a good spectral collection and also spectral database for organic compounds is another good source.
Thanks everyone for the answers... I have tried many sources and indeed sometimes it is tricky to choose solvents.
https://pubchem.ncbi.nlm.nih.gov/
here you will find everything you need.
Best wishes
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