I created a spectrometer that produces nice clean wavelengths, I calibrated it using a fluorescent bulb. spectrumfrom that I can create a graph from the data. graph after which, I use the known position to of emission lines (Blue: 405.4 nm, Bright Purple: 436.6 nm, Brightest Green: 546.5 nm) to scale the graph to its proper wavelength.

I have done all of that, I'm planing on using a xenon bulb with a Borosilicate test-tube filled with water. The water will have unknown contaminates. But from the xenon spectrum of the water, how do I known whats in the water?

Ive looked at beer's law, but that just tells you the consecration of the unknown substance in the water. I have model my spectrometer from commercial ones that from a test tube and a xenon bulb can tell you whats in the water.

There must be some formula describing the absorption spectrum of a element and how to find that element inside a spectrum of unknown.

thanks in advanced, Pascal R. Jardin


Commercially-available, computer-controlled spectrophotometers have hundreds of thousands of known spectra loaded into the controller's memory, from which the controller will furnish a best match after the unknown spectrum has been captured. Prior to computer control, the test operator had to do the spectral matching by hand and eye using a catalog of published spectra. What you will need to do is to get hold of a hard copy of one of those spectrum catalogs.

  • $\begingroup$ thank you Niels Nielsen, do happen to know if there is a catalog of the absorption spectrum of all of the elements? $\endgroup$ – Pascal R. Jardin Aug 3 '18 at 0:50
  • $\begingroup$ I know that the absorption spectrum can be used for gas, I now have a project that requires gas to be analyzed, but can it also be used for water analysis? $\endgroup$ – Pascal R. Jardin Aug 3 '18 at 0:52
  • $\begingroup$ yes it can, and is. regarding absorption spectra, you will have to search for a source yourself. $\endgroup$ – niels nielsen Aug 3 '18 at 6:25
  • $\begingroup$ I know what I need to do know, I need to get the absorption spectrum of all elements. Once I have that, I can determine whats in the air and whats in the water. Thank you for your help! :) $\endgroup$ – Pascal R. Jardin Aug 3 '18 at 18:01

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