I want to measure the absorbance spectrum of some solutions, in the 400-700 nm range. I've always used regular "optical glass" cuvettes for this. But I've been wondering, is this really necessary?

If the glass looks transparent to the eye, then its absorbance in the 400-700 nm range is negligible. And if the surface looks smooth and clear, then it shouldn't disperse the incident light. So any thin sheet of smooth transparent glass should work, right?

For example, I could try to build my own cuvette simply by getting a few microscope slides and tops, (which are thin, flat and smooth panels of glass) and gluing them together with a suitable adhesive.ç

Edit: What I mean is, creating a hollow 3D shape with 4 rectangular panels and a smaller square bottom panel, by gluing thin pieces of flat smooth glass (microscope slides for example). This would be a "home-made" cuvette. (I'm not proposing to simply sandwich a droplet between to slides!)

Has anyone tried this? Is there a reason why it wouldn't work?

  • $\begingroup$ Cuvettes hold a very specific volume of solution, but microscope slides don't hold liquid at all (besides maybe droplets whose thickness depends on surface tension). What are you actually trying to do here? $\endgroup$ – KF Gauss Jun 6 '20 at 0:56
  • $\begingroup$ @KFGauss: You're right but it's the optical path length that matters. $\endgroup$ – Gert Jun 6 '20 at 6:38
  • $\begingroup$ The point is that you can't calculate the optical path length if you don't know the physical length if the path. A microscope slide won't allow you to do that conversion, but a cuvette would. $\endgroup$ – KF Gauss Jun 6 '20 at 10:32
  • $\begingroup$ @KFGauss: What I meant was, glue 6 panels of thin glass together to create an actual cuvette, that is, a hollow 3D shape (square-based prism, open top) which is perfectly capable of holding a solution, and having a very much defined light path. A home-made cuvette. I thought that was clear, but I'll edit the question. $\endgroup$ – Juan Perez Jun 6 '20 at 14:16

Yes you can do that. The only thing to watch out for is that microscope glass is usually borosilicate glass but cuvettes are typically made of quartz. You can always take a calibration measurement to account for this difference anyways.


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