By Dominique Trudel on Monday, October 11, 1999 - 02:03 pm:
I study organic chemestry in a college level, and I have a lab report to do on chromatography. Though, I have to explained why do we use water:ethanol:vinegar ( 10:50:1) and chloroform:methanol:ammonia 17% (40:40:14) as solvent.
Use of silica gel has to be justified, and ninhydrine as a reagent too.
I have already found some hints, but home and school resources are old (two books of 1967 are the most recent!). Thanks a lot for your help!
By Andrea Applegreen on Wednesday, October 13, 1999 - 10:57 am:
Hi Dominique
The type of mobil phase(solvent mixtures you mentioned) you choose depends on the compound/s that you are trying to separate. What kind of sample mixture are you trying to separate?
Silica gel is used as the stationary phase in which the separation of your sample will take place.
By Anonymous on Wednesday, October 13, 1999 - 11:22 am:
Are you trying to detect some sort of amine? Ninhydrin is good for that.
By Dominique Trudel on Thursday, October 14, 1999 - 12:08 pm:
Hi Andrea!
I have to separate amino acids(lys-met-val-pro-asp-asn-leu-gly)... In fact, it is already done, but I have to explain why did I used those compounds. Thanks a lot for your help!
to anonymous: I used ninhydrine... why is it so good?
By Anonymous on Saturday, October 16, 1999 - 04:42 am:
I don't know why it's so good, but the crime labs have used it to detect the amino acids left behind when something is touched by human fingers--spray area with ninhydrin and look for fingerprints to pop out!!
(that's just a neat fact, has nothing to do with LC at all!)
By Anonymous on Monday, October 18, 1999 - 10:31 pm:
2 ninhydrine molecules react with one molecule of aminoacid at pH 5 to give a colored dimer (containing now a nitrogen atom) called Ruhemann's purple.
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