Excellent article, and nice work for an undergrad project! Most undergrads don't even know Raman spectroscopy outside of one lecture in analytical chemistry. In 2004, while I was with Ion Track Instruments, a division of GE Security at the time, I created a bottle liquid scanner prototype for HM Customs (UK) for the detection of dissolved narcotics in various alcohols, which was tested at the Gatwick airport in 2005. It featured an interlocked sample chamber similar to the one you discuss. I tested this with a wide variety of alcohols, and through a wide range of different bottle types, colors, thicknesses, and shapes, so that the bottles could be scanned without opening them. We used benzocaine and similar drugs as cocaine surrogates. I never published that work, as the data was owned by HM Customs, and they did not want it advertised, so you would not have encountered anything on that work.

I was a bit surprised that you did not reference in your thesis some of the pioneering work in Raman liquid bottle scanners that are in the public domain. In 2008, TSA solicited suppliers for bottled liquid scanners. In 2010, ICx introduced a liquid bottle scanner, although there is no good data on the unit. In 2011-12, Smiths Detection, I believe in part as a result of funding from the TSA program from 2010) introduced the RespondeR BLS (Bottle Liquid Scanner, and, the next year, was awarded a $6.8M contract from the TSA for deploying these around the US. They became the 'de facto' standard for liquid bottle screeners at major airports. I am not certain if they are still in use, though.

NOTE: I had provided links to the references above, but Hashnode said I cannot include links in my comments since I am a new user. If you are interested and cannot find them, let me know via my email below and I can send them.

Good luck in your pursuit of a Ph.D., and I look forward to seeing some of your work published!

Scott Sutherland, Ph.D. Spring, TX sutherlandws@gmail.com