Arduino-based Raman spectrometer for drug identification

[sbrothy]

Well, my project is moving forward, albeit slowly as it takes time for things to arrive from China. I mostly have all the cheapest items now. The optic parts are pretty expensive though.

I'm not trying to fool anyone: I'm in way over my head here. Luckily I don't need to understand the theory in detail to actually build the thing, but some things naturally puzzles me being an autodidact hack.

My latest acquirement is an infrared camera, so now, as mentioned, I'm "just" missing the optics and filters (perhaps some heat sinks).

i have a bunch of questions for you here, let me just find them....

 

[sbrothy]

OK,. Q#1:

In summary, the design and fabrication of a cost-effective
portable Raman spectrometer are presented here. The
simplicity of the fabrication procedures detailed herein and
the nominal cost of materials make it easily achievable at any
educational institution. The design strategy provided in the
manuscript offers the flexibility of configuring Raman systems
with a different excitation wavelength, and the only
modification to be implemented will be the choice of the
long-pass filter with the right cutoff wavelength. This helps to
explore other capabilities of RS. For example, configuring the
system with 405 nm allows study of the well-known resonance
Raman effect, which provides a 106 signal enhancement with
biologically important molecules such as heme and chlorophyll.
On the other hand, configuring it with a longer
wavelength laser diode (e.g., 650 nm) will help record the
Raman spectrum with reduced fluorescence. Yet, another
possibility is to explore the demonstration of the concept of
SERS with easily preparable metal nanoparticle solutions,48−50
which yield enhancement factors as high as 1010.

---- Fabricating a Low Cost Raman Spectrometer... (boldness mine)

Now my question is: if I want to detect organic compounds like illicit drugs and adulterants, what nm should I use?

 

[sbrothy]

I was searching for answers to my question among ready-made systems. And even though I was already aware the prices still shocked me. I'm guessing you get what you pay for though. These gizmos look really smart! And they're only ~$22.000!

Zurich Instrumensts

Raman Systems

 

[sbrothy]

Well OK. If I want a real beamsplitter (an aluminium coated glassplate as opposed to a transparent cube) it\s gonna cost me around 300 Euro! and the optics are in the same neighborhood. Also, I never got the cutoff filter but then that\s it. But I can see now what the expensive parts are. Not so surprising though: high quality optics. Its gonna take a couple of month more to amass all the parts.

 

[Mayhem]

Spectroscopy equipment is notoriously expensive and there's probably a reason beyond profit.

At best you would be able to say "this is impure" and when someone asks "with what?" just shrugging and smiling would be the best answer. And street narcotics will without be impure.

Chemists constantly face a similiar issue where they have some powder that's supposed to be completely white, but it's vaguely stained brown / yellow for some reason. Recrystallization is a very common bulk purification method for such instances.

Even if you have a mixture of compounds that are all similarly soluble in your crystallization solvent, the compound in excess will preferentially crystallize out. The downside is you won't know if something else has cocrystallized, but if the thing you're trying to avoid is also a drug (like fentanyl), it would show up on a testing kit? Maybe I'm naive regarding what's readily available to citizen.

Challenge might be (legally) sourcing good crystallization solvents. 96% Ethanol and acetone are easy to get anyway, but things like methanol and diethyl ether may be regulated (for good reason). Then again, this pursuit seems less about getting it perfect and more about making it better.

 

[sbrothy]

Spectroscopy equipment is notoriously expensive and there's probably a reason beyond profit.

At best you would be able to say "this is impure" and when someone asks "with what?" just shrugging and smiling would be the best answer. And street narcotics will without be impure.

Chemists constantly face a similiar issue where they have some powder that's supposed to be completely white, but it's vaguely stained brown / yellow for some reason. Recrystallization is a very common bulk purification method for such instances.

Even if you have a mixture of compounds that are all similarly soluble in your crystallization solvent, the compound in excess will preferentially crystallize out. The downside is you won't know if something else has cocrystallized, but if the thing you're trying to avoid is also a drug (like fentanyl), it would show up on a testing kit? Maybe I'm naive regarding what's readily available to citizen.

Challenge might be (legally) sourcing good crystallization solvents. 96% Ethanol and acetone are easy to get anyway, but things like methanol and diethyl ether may be regulated (for good reason). Then again, this pursuit seems less about getting it perfect and more about making it better.

I'm not sure I understand you correctly. But if I communicate that this is for reducing OD deaths I may get a better deal.

Was that your point?

EDIT: Naah, are you a chemist or pharmacologist?

 

[Mayhem]

I'm not sure I understand you correctly. But if I communicate that this is for reducing OD deaths I may get a better deal.

Was that your point?

EDIT: Naah, are you a chemist or pharmacologist?

Chemist.

 

[sbrothy]

Chemist.

I would appreciate your contious input. Please return.

Chemist.

I’m gonna need you. I hope you’ll return to this thread.

 

[sbrothy]

I have questions I’d like to ask. But it’a gonna take me some time. As I said I’m a selfthougt hack, and I’d like real input from people who are educated.