Spectrographic identification of compounds?

[Bercilak]

It would be nice if pill testing was easier and cheaper. Sending a sample off to have MS or NMR analysis done isn't cheap and the turnaround time isn't great either. The Intel Science Talent Search just announced their winners, and the winner developed a cheap spectrograph system.

I'm not an organic chemist, though. Anybody know if a spectrograph is a useful way to identify compounds typically in pills, or am I stuck waiting for somebody to develop a $300 MS setup?

 

[duck_racer]

Well aromatic rings have a an absorbance which can easily be read..

LC-MS for accuracy though :D

 

[phase_dancer]

I've looked at using absorption spectroscopy for the ID of drugs. Something I was working on around a year ago involves first reacting an amine with one of two chemical agents (trade secret) to produce compounds with a very sharp and well defined absorbance peaks.

Different drugs would produce various absorbtion peaks within the visible spectrum. Funding became the big hurdle, but if the idea could be developed further, I've no doubt whatsoever that an inexpensive pocket sized LED spectrometer could be developed to suit.

 

[PlurredChemistry]

spectrography simply will not work for pill analysis. the aromatic absorbance in MDMA will be too similar to many other simple aromatics. alot of things used to press (as well as cut) pills will have a similar absorbance.

LCMS and GCMS work because the LC (or GC) seperates the compounds before sending them through the MS which identifies each individual component.

without this sepratory step you're not going to get too much information from a pill...

 

[phase_dancer]

spectrography simply will not work for pill analysis. the aromatic absorbance in MDMA will be too similar to many other simple aromatics. alot of things used to press (as well as cut) pills will have a similar absorbance.

The agent I mentioned above, on reaction (catalysed) with different (but structurally similar) amines forms compounds that have remarkedly different absorbance characteristics.

 

[PlurredChemistry]

sorry, i didn't read that...

you're right, and i could see this working by forming some sort of benzyl amide derivative (or maybe making an azobenzene from a diazonium salt - but there are loads of problems with the azo reaction). further, some things used to cut/make pills will react using either of these methods (asprin, acetometophin, lactate, etc). my main concern is the mixture of compounds, especially as the MDMA is in such a small amount in comparison to the fillers present...

the entire point of developing a low cost/easy to use system is so average people can pop a pill (or scrapings) into a machine and get a reading. anything beyond a simple acid/base reaction i reckon would be too difficult for the average pillhead.

PM me. i'd like to discuss this in depth. my analytical chemistry is mediocre at best...

 

[protovack]

You still need to have a pure compound to get a reliable spectrum ID. As others have said, "pills" will contain a variety of compounds.

It seems like getting the pure compound would be the hard part for the average person. BTW, what would be the best method for doing this?

 

[duck_racer]

^Chromatography