Question: What's an easy way to compare two liquid samples with a spectrometer?

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warren asked on October 20, 2017 17:50
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I'm interested in sharing out an activity on comparing two samples -- a "control" of distilled water and a sample of, say, river water -- to determine the opacity or #turbidity of the sample. I'm guessing the difference in color will be pretty minor, and may not be very easy to measure, so what's the best way to do this with:



spectrometry turbidity foldable-spec

question:spectrometry question:foldable-spec question:spectrometry-challenge question:spectrometry-turbidity question:lego-spectrometer



6 Comments

warren 3 months ago

Hi, @programmer1200 -- saw your post on a cuvette holder and wondered if it would be possible to use it for two cuvettes simultaneously? Perhaps by modifying the design?

programmer1200 3 months ago

Yes it is possible to redesign it for two cuvette at one time would just need to widen the area toward the spectrometer and double the area on the top. If you like I could here in the next week get started on a mod version.I'm curious what would be your need to examine two cuvettes at one time?

warren 3 months ago

This can be a helpful way to get the same exposure for two samples at once, which can be important when using a less-controlled camera like a webcam. That way you're not worried that the exposure settings would be different -- as long as the light is hitting both sample containers identically!

warren 3 months ago

We had an old idea for this a ways back -- posted below. But yours connects so beautifully to the spectrometer, it's a great improvement!

warren 2 months ago

Related:

How can we detect contaminants in water samples with a DIY spectrometer using reagents?

https://publiclab.org/notes/warren/12-18-2017/can-a-diy-spectrometer-be-used-to-measure-water-turbidity

warren 2 months ago

It would also be really cool to see a design adapted for the Lego Spectrometer!

https://publiclab.org/wiki/lego-spectrometer

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2 Answers

Here's one attempt from a few years ago: https://publiclab.org/notes/cfastie/02-25-2014/mobile-cuvette-holder

This was designed for a laser, but could be adapted for back lighting via LED as well.

Photo and captions via @cfastie:

2-cuvette


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