Jump to content
The Corroboree
Sign in to follow this  
cactuscarl

pocket spectrometer

Recommended Posts

I'd be worried about accuracy. Heaps of compounds can skew the results of other compounds. And there are usually limits as to how concentrated the sample can be.
Then if you are doing surface spectrophotometry it is generally light that hits the surface and is then refracted through a small crystal to measure the spectrum.
I'd think that optics similar to that used in cell phones (which is what they claim) wouldn't be able to get the kind of accuracy you might be hoping for.

But in saying all that they may be using something completely new and optimised for exactly this and it might be able to do what they claim and categorize a near infinite number of molecules.
Unless they publish the technical details behind how it's working (highly unlikely considering its a commercial product :P) it would be hard to make a truly educated call about it without trying it out.

Best of luck. Let us know how it goes if you do end up trying it

Share this post


Link to post
Share on other sites

Cheers for the input. I had my doubts about it.... I knew someone here wgo be able to shed some light on it for me.

Share this post


Link to post
Share on other sites

I tend to agree with what Ace said above, I really can't see those things giving an accurate measurement of spectra/spectrum, especially on a surface sample from a leaf ect.

That's not to say to that it wouldn't have its place though. After you'd analysed enough samples of known quantity then after a while I suspect that even though the results would be skewed by many confounding factors, eventually you'd get enough data to recognise a fingerprint from many samples.

The same could apply to a sample of an isolated compound on a slide too - skewed results with a recognisable fingerprint.

I'd love to play around with one.

I found a diy spectrometer that was being developed on a crowdfunded program a while back. It's now a finished project and they are selling the units quite cheap and also have details on how to build your own.

http://publiclab.org/wiki/spectrometer

There's a few different models, a stand alone USB unit and one that attaches to a smartphone. There's fuck all to them - basically they are just a webcam, a darkbox and segment from a CD/DVD to split the wavelengths of light. There's a software kit that goes with it to help with the analysis.

I also have serious doubts about the accuracy of such a device but as above if you take enough samples and gather enough data then eventually you'd identify some fingerprints of likely suspects. It could be good enough to use it to decide if further analysis with GCMS would be a waste of time or not.

I still plan to build one but I'd probably build mine with a double diffraction grating system to (hopefully) give greater separation of spectra and improve accuracy. If I could source a digital camera cheap enough that can see further into the UV range of the spectrum then that would be plus for me. Many alkaloids absorb and emit in that range, so that would give it a bit more versatility and make it worth the effort. It would probably need to be tweaked for different light sources (UV) too.

Edited by Sally
  • Like 2

Share this post


Link to post
Share on other sites

That's not to say to that it wouldn't have its place though. After you'd analysed enough samples of known quantity then after a while I suspect that even though the results would be skewed by many confounding factors, eventually you'd get enough data to recognise a fingerprint from many samples.

http://publiclab.org/wiki/spectrometer

There's a few different models, a stand alone USB unit and one that attaches to a smartphone. There's fuck all to them - basically they are just a webcam, a darkbox and segment from a CD/DVD to split the wavelengths of light. There's a software kit that goes with it to help with the analysis.

Definitely if you did enough samples you could build your own model

For example if you could find some kind of relationship between a compound of interest and a reading, regardless how skewed, then you could theoretically take enough samples to create a model that worked for that particular crude data.

The public lab spec is ok. I think double diffraction grating could weaken the light signal though

Im sure with enough playing around and modding you could rig up a reasonable spec.

Wouldn't have textbook perfect results (what does) but you could build some reasonable models for your own stuff.

Keep us posted on any experimentation :)

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×