Who can forget Cuba Gooding Junior in the movie Jerry McGuire shouting “SHOW ME THE MONEY!”???
If he was an analytical chemist or a DUI defense attorney facing a purported result from a Headspace Gas Chromatograph with a Flame Ionization Detector, he would yell:
“SHOW ME THE SEPARATION!!!!!!”
Well, that is one of the things that a good criminal defense attorney who specializes in defending the citizen among us who has been accused of a DUI should always demand whenever there is a reported result from a chromatographic process.
As I posted before in Gas Chromatography and why is it is so important to Pennsylvania DUI arrests:
Chromatography is strictly and simply speaking “separation science”. It is the study of how an analyst can take a complex matrix (compound) and separate it out into its component parts.
If you can’t prove separation between like analytes, then your result means nothing.
Much like I posted before “A large problem in Gas Chromatography: No uniform standard for GC run position or composition“. There is also no uniform nomenclature for what this is called.
I have seen it called:
- Resolution Control Standard
- Separation chromatogram
- Matrix chromatogram
- some don’t call it anything at all (because they don’t do it)
For ETOH determinations at a minimum we need to see this proof of separation for from standards that are NIST certified values or comprised of USP grade materials (see generally: Metrology in DUI prosecution for the importance of these concepts):
- ethyl acetate
- methyl ethyl ketone
Below is an example of just such a type of proof:
-Justin J. McShane, Esquire, Pennsylvania DUI Attorney
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