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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: asqa on June 18, 2005, 01:55:51 AM

Title: Chemical formula
Post by: asqa on June 18, 2005, 01:55:51 AM
is there any single analytical method available for determining unknown compound chemical formula? if so what,s that method? how it works? where is it?
Title: Re:Chemical formula
Post by: DrCMS on June 18, 2005, 04:38:37 AM
High resolution accurate mass spec to determine empirical formula.  It can't tell you which issomer you have for sure. So you'd need high res MS-MS to get that info.
Title: Re:Chemical formula
Post by: Qazzian on July 16, 2005, 09:23:36 PM
Using a mass spect will give you the emperical formula, and then size exclusion chromatography with standards can give the size of the molecule, so you can figure out the molec. formula.
Title: Re:Chemical formula
Post by: lemonoman on July 16, 2005, 10:47:12 PM
There is, of course, no SINGLE analytical method where you can just put in the sample and it'll tell you what it is (out of all possible chemicals).  This isn't CSI lol...

But analytical chemistry IS coming closer...and there's a pile of options.  You can look into GC×GC, GC-MS, high res MS-MS as DrCMS suggested, or use a combination of techniques as Qazzian suggested (just google those terms if you're not exactly sure what they are - or ask here, I suppose :P)

If this is for an specific application, and you have an idea what the compound is, then some methods will be MUCH better than others.  If this is just a general question then no...but chemistry research is getting there.
Title: Re:Chemical formula
Post by: Qazzian on July 17, 2005, 01:02:24 AM
Sheesh, just because you're writing a paper on 2D GC, you throw it around like it's candy and you're some kind of candyman. ::)

But back on topic, is this for a specific application, or is this more a general question? You didn't really specify too much in your original post.
Title: Re:Chemical formula
Post by: asqa on July 20, 2005, 08:03:44 AM
general purpose only