[Fal]

Hello All!

I'm brainstorming some ideas for a final year undergrad project involving the use of GC MS analysis in Forensics (I thought this was narrowing it down but certainly not!) A lot of what I'm finding is related to arson--petrols and drug identification. What else is out there? Or even with petrols and drugs, what's something specific which could blossom into a project?

Looking forward to hearing your responses

[Archer]

Hi,

I used to lecture Forensic and Analytical Chemistry and you have pretty much identified the main uses of GC-MS in mainstream Forensic Practice.

The issue that you face is that GC can only analyse volatile substances so unless your department has Pyrolysis GC-MS then you can't look at polymers such as fibres or various plastics etc.

Drug analysis would be by far the most interesting project (fire accelerants are not particularly interesting by GCMS as petrol contains mostly aliphatic hydrocarbons) but you may struggle to obtain the materials to test.

One thing which is quite interesting is the the cross reaction between diamorphine (Heroin) and the common cutting agent paracetamol (Tylenol if you are in the USA) upon injection. During the analysis a transesterification reaction occurs to make 6-monoacetylmorphine (6-MAM)  and 4-(acetylamino)phenyl acetate as artefacts. This is a nuissance if one is attempting quantitative analysis of diamorphine so the sample prep has to include a derivatisation step. Interestingly this cross reaction also occurs with paracetamol and aspirin when they are mixed making aspirin a good substrate to work with for method development. It is possible to tweak the parameters of the instrument to avoid this cross reaction. This makes quite an interesting project which has real applications but can be carried out without the need to handle a controlled drug.

[Babcock_Hall]

I seem to recall a poster at the 2012 SERMACS meeting in Raleigh, NC in which it was shown that during injection, one compound was converted into another.  It seemed that this confounded the analysis in some way (I believe that the other compound was a controlled substance but the first was not).  I don't recall whether or not any mass spectrometry was part of the analysis.  It might be worth searching throught the abstracts there.

[ironnica]

Babcock, I believe you are referring to derivatisation. If you open it up to CE-MS or LC-MS it may get a lot more interesting. As far as I remember, CE can be used a lot with macro/biomolecules

[Babcock_Hall]

IIRC There was an unintended chemical reaction taking place during the analysis, but the details escape me.  Here is the title of a poster at SERMACS 2013:  137. Chemistry Expertise in the Courtroom: When Does Methamphetamine Exist in a Clandestine Drug-Lab Manufacturing Evidence Sample? Sometimes It Depends Upon Who You Hired to Evaluate the Analytical Data. A Case Study. E. G. Brown"

[Babcock_Hall]

GC/MS would have cracked the Patricia Stallings case right away.  What a shame it was not as widely available at the time.
http://justicedenied.org/patriciastallings.htm

[Fal]

Thank you guys

So much information out there which I'm so new to! Just about to have a meeting with a lecturer and guest professor who works in one of the Forensic Labs over here.