Raman is based on IR but instead of transmission it looks at changes to frequency of scattered light, so you can have your detector outside the sample rather than around it. IIRC, the handheld ones have the incident light focused a few cm from the probe, so you can probe through a clear plastic bag without picking up too much of the signal from the bag
A company in which I've made a small crowdfunded investment, Mariposa Technology, is using Raman spectroscopy to allow hemp farmers to stay within legal limits for THC content:
As with the substances which the Anton Paar device seeks to detect, Mariposa's tech also relies on a database which maps the device-acquired data against known patterns for chemical compounds.
This is a great essay. The amount of wishful thinking that both the public and law enforcement engage in when it comes to interdicting drugs or other illegal things at the border would strike me as implausible were I not so cynical about people.
I know a guy who worked at a company called "Passport Systems" developing a cargo-scanner. (Alas, the company ran out of money and shut down a few years ago.) They developed techniques to scan shipping containers that were much fancier than normal x-ray scanning, like I think they would send in gamma rays at lots of different energies and measure what happens. E.g. one of the things they used is called “nuclear resonance fluorescence”. They claimed to be able to distinguish at least some organics from each other, based on things like measuring density and atomic number independently, and measuring the carbon-to-oxygen ratio, etc. See for example slides 7 and 11 of https://accelconf.web.cern.ch/napac2016/talks/thb2io01_talk.pdf
I have been using handheld Raman spectrometers to nondestructively ID organic substances from a distance, back in 2014. Like this one
https://www.anton-paar.com/us-en/products/details/handheld-raman-spectrometer-cora-100/
Raman is based on IR but instead of transmission it looks at changes to frequency of scattered light, so you can have your detector outside the sample rather than around it. IIRC, the handheld ones have the incident light focused a few cm from the probe, so you can probe through a clear plastic bag without picking up too much of the signal from the bag
That's a terrific summary, Chebky. Thank you!
A company in which I've made a small crowdfunded investment, Mariposa Technology, is using Raman spectroscopy to allow hemp farmers to stay within legal limits for THC content:
https://mariposatechnology.com/
As with the substances which the Anton Paar device seeks to detect, Mariposa's tech also relies on a database which maps the device-acquired data against known patterns for chemical compounds.
This is a great essay. The amount of wishful thinking that both the public and law enforcement engage in when it comes to interdicting drugs or other illegal things at the border would strike me as implausible were I not so cynical about people.
No mention of NMR?
I know a guy who worked at a company called "Passport Systems" developing a cargo-scanner. (Alas, the company ran out of money and shut down a few years ago.) They developed techniques to scan shipping containers that were much fancier than normal x-ray scanning, like I think they would send in gamma rays at lots of different energies and measure what happens. E.g. one of the things they used is called “nuclear resonance fluorescence”. They claimed to be able to distinguish at least some organics from each other, based on things like measuring density and atomic number independently, and measuring the carbon-to-oxygen ratio, etc. See for example slides 7 and 11 of https://accelconf.web.cern.ch/napac2016/talks/thb2io01_talk.pdf