RTI scientists solving forensic, designer drug mysteries
Catching up on my reading this Sunday morning, I'm beaming with pride on the collective accomplishments and coverage of some old friends and colleagues.
Kerstin Nordstrom, a AAAS Mass Media Fellow with the Raleigh News & Observer, had a nice story on 3 September about the work of Dr. Peter Stout at RTI International. You old-timers will know this non-profit entity as Research Triangle Institute, home to the discoveries of Taxol and camptothecin by Wall and Wani and colleagues.
Kerstin, or Dr. Nordstrom I should say as she holds a PhD in physics, interviews RTI's Dr. Peter Stout on the institute's forensic analytical chemistry capabilities with regard to the "designer drug" industry. Yes, here we go again with my long-running commentary on the "synthetic marijuana," "herbal incense," "plant food," and "bath salts" products that have recently taken a direct hit from "Operation Log Jam," a coordinated, federal operation to shut down the industry.
Kerstin Nordstrom, PhD, AAAS Mass Media Fellow, News & Observer. Credit: Losert Laboratory/Univ of Maryland.
In my post on the federal takedown, I referred to a paper by Stout's RTI colleagues where mass defect filtering was used to identify unknown analogs of known illegal compounds, particularly the JWH group of cannabimimetic naphthoylindoles (Anal. Chem., DOI:10.1021/ac300509h).
(Addendum: That paper was also covered nicely in the 15 June C&EN by Erika Gebel.)
Coincidentally, both Kerstin and Peter are dear to me - hence the following disclosures before singing the praises of the article: Peter earned his Ph.D. in molecular toxicology from Dr. Jim Ruth's lab at my former home, the Department of Pharmaceutical Sciences at the University of Colorado Denver's Skaggs School of Pharmacy. My time at RTI's Natural Products Laboratory (2002-2008) overlapped with Peter's hiring. As an aside, I had not known Peter was hired until he saw a cart outside of my laboratory with my name and hunted me down, guessing there weren't many Krolls in biochemical pharmacology. An equally lighthearted observation is that Peter has almost completely shaved his head as long as I've know him; I'm certain that's a coincidence with his dissertation research project, "Mechanisms of Drug Disposition into Hair."
Disclosure #2: Kerstin is a fellow graduate of the 2011 Santa Fe Science Writing Workshop and serendipitously ended up here in the Triangle for her AAAS Mass Media Fellowship.
What I like about the story is how both of them describe analytical techniques in relatively approachable language:
Kerstin on HPLC:
Peter Stout, PhD, forensic toxicologist at RTI International. Credit: Jimmy Crawford/RTI
For liquid chromatography, an unknown chemical is pushed through a pipe. The pipe is filled with tiny silica particles – 1 to 10 micrometers in size – that attract some molecules and repel others. Each chemical has a different attraction, and so some, attracted to the grains, go slower than others. The separated components come out one at a time.
Each chemical can then be identified.
On mass spectrometry, Kerstin again:
Another identification technique used in Stout’s lab is mass spectrometry. Once a chemical is isolated, individual molecules are then shot through a sealed high-vacuum container. One kind of mass spectrometer measures the time it takes the molecule to hit a fixed-distance target, an indirect measure of its mass. Testers might then break apart the molecule, and analyze the mass of its fragments.
By taking many, many measurements of the same chemical, they build up statistics, and can deduce the chemical formula of the molecule.
And together with Peter on ion mobility mass spec:
Other methods yield complementary information. Ion mobility measurements, for instance, get the shape of the molecule. “It’s like throwing a crumpled piece of paper versus a spread out piece of paper towards a fan,” said Stout of the process.
Sure, some jargon remains. But I think they did an effective job on helping the reader appreciate the challenges of forensic chemistry and the technology that can be used.
Well done, you young whippersnappers!
Nordstrom K. Triangle researchers try to ID composition of 'designer drugs.' News & Observer, 3 September 2012.