# DIY spectrometry



## Evan2468WDWA (Jun 17, 2014)

Could something like this help identify metals and their purity?
https://www.kickstarter.com/projects/jywarren/public-lab-diy-spectrometry-kit


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## justinhcase (Jun 17, 2014)

Waaw!! that is just amazing.
I wish I could start again with all that is becoming available.
Wish I could see what will happen in a few hundred years.
That is one kit I will give a go.
10 out of ten to them!!!


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## SCB (Jun 17, 2014)

Evan2468WDWA said:


> Could something like this help identify metals and their purity?
> https://www.kickstarter.com/projects/jywarren/public-lab-diy-spectrometry-kit



Probably... Maby not very practial but as a reflection, absorption and flourescence device you could probably disolve a metal sample and run the solution through the spectrometer. But impuritys in the acid and unknown concentrations would be a pain in the ***, so good chemistry skills, clean chemicals and equipment are important to get a useful reading.
A better way to analyse a metallic sample is with atomic emission spectrometry, It gives faster and cleaner results but is more complex process... Not impossible to build at home, just harder. 8) 

A real metallurgical spectrometer is a quite big piece of equipment and the testing procedure is as follows:
The sample to be tested is ground flat and placed in the spectrometer. Under a controlled atmosphere (usually He) an electric arc goes between a (usually W) electrode and the sample. The arc rips off atoms from the sample and when these atoms pass the plasma of the arc they emit their unique spectral lines.
The light passes some optics and is spread out over a long sensor array to be detected.
Nifty software compensates for the interference from the electrode and the atmosphere and presents the result.


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## justinhcase (Jun 17, 2014)

If you just set it up to check Platinum group chlorides at the end of processing would it not be able to detect the amount of contamination and % of each P.G.M. in solution?
Don't really need to know what the contaminates are in detail.


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## SCB (Jun 17, 2014)

if you only look for a specific elements lines there is a risk your reading may be incorrect. 
To get a correct reading on Pt you must also identify all other elements present that have spectral lines at the samt wavelength as Pt.
Pt have a line at 539.0 nm and Fe have one at 539.2. With a low resolution sensor it will be hard to discriminate unwanted signals, to get a unique fingerprint of Pt you have to have a high enough resolution or sort out all lines that are shared with other elements, wich means you have to identify them as well.

But, if one has made all the trouble making a good solution of a sample, it would probably be faster and easier to analyse the content chemically.
Or get an XRF. 8)


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## justinhcase (Jun 17, 2014)

I love this place .
You can get a better education for free than most university's charge tens of thousand of pounds for.
Thank you very much :lol: :lol:


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## Evan2468WDWA (Jun 18, 2014)

SCB said:


> Evan2468WDWA said:
> 
> 
> > Could something like this help identify metals and their purity?
> ...


Thanks for the information. I think that I could maybe make a crude atomic emission spectrometry device using a something similar to what this guy made, and the optics from a rear projection TV. Truthfully though I doubt I'm handy enough to pull it off. The software would be especially problematic for me because I lack programming skills. If the kit from the link could be made to work for me it would be a lot easier. Especially sense the software is already written. Even if the device isn't perfect it's still far superior to my naked eyes. I've been reading in Hoke's book about Stannous Chloride. If I use the device to record positive results for different precious metals then maybe the device can be used to detect those results again even when my own eyes are not up to the task. I'm especially interested in what they said about a Wikipedia of data that they are collecting. Having access to data from a lot of different chemicals would make the device much more useful. At least that's what I'm hopping would be the case. It would be really cool if people recorded date for a lot of different alloys of gold so that the device could tell you what carrot gold you have.


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## macfixer01 (Jun 18, 2014)

I'm not sure how well an acid solution would work for our purposes since it would introduce even more impurities. Burning or vaporizing a sample might be necessary, like a flame loop test. Yes for an automated device you'd need it to have adequate resolution to differentiate elements with similar lines. I believe multiple lines are present for every element though, and are always varied enough to tell apart if given enough spatial separation at the viewing point to see them distinctly (for example a magnified or projected image)? If so then compared in their totality there shouldn't be too much problem differentiating between the elements in a sample. That's assuming the sample doesn't contain dozens of different elements, and as long as you have a good library for comparison. The major problem I think is that even minor contamination by elements like sodium can totally overpower other lines and make them hard to see. Also spectroscopy at this level is pretty much only a qualitative test. You'd see lines for all the elements which a sample contains, but couldn't tell in what amounts they exist.

If you just want to see the spectral lines and manually compare them against a reference, a really basic spectrometer can be made from a cardboard tube spray painted black inside and having a slitted cap on one end which is backed on the inside with a piece of plastic diffraction grating material. Edmund Scientific sells diffraction grating and probably most other science suppliers do also.

macfixer01


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## Evan2468WDWA (Jun 18, 2014)

macfixer01 said:


> I'm not sure how well an acid solution would work for our purposes since it would introduce even more impurities. Burning or vaporizing a sample might be necessary, like a flame loop test. Yes for an automated device you'd need it to have adequate resolution to differentiate elements with similar lines. I believe multiple lines are present for every element though, and are always varied enough to tell apart if given enough spatial separation at the viewing point to see them distinctly (for example a magnified or projected image)? If so then compared in their totality there shouldn't be too much problem differentiating between the elements in a sample. That's assuming the sample doesn't contain dozens of different elements, and as long as you have a good library for comparison. The major problem I think is that even minor contamination by elements like sodium can totally overpower other lines and make them hard to see. Also spectroscopy at this level is pretty much only a qualitative test. You'd see lines for all the elements which a sample contains, but couldn't tell in what amounts they exist.
> 
> If you just want to see the spectral lines and manually compare them against a reference, a really basic spectrometer can be made from a cardboard tube spray painted black inside and having a slitted cap on one end which is backed on the inside with a piece of plastic diffraction grating material. Edmund Scientific sells diffraction grating and probably most other science suppliers do also.
> 
> macfixer01


I'm starting to think that the easiest thing to do would be to forget about using spectrometry, and to focus on learning how to use normal methods.


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