How do you test liquid or solid samples with your DIY Spectrometer? Read about ways to prepare and scan samples here, and read about different tests you can do with your spectrometer.

Sample containers

A good sample container has flat sides, so you can shine lights (and lasers) through it without lots of reflections. It's also good to have the light travel through a consistent amount of the sample -- many cuvettes (traditional spectrometry sample containers) are 1cm x 1cm, so the light always goes through 1cm of the sample.

A square-sided bottle, left, and a cuvette, right (photo from Wikipedia.

Water samples

Water is usually very clear in small amounts -- even murky water in a small container will look pretty transparent. That makes it hard to measure with spectrometry unless you shine light through a lot of it. But some tests have been done -- see this example of a scan of water from the Charles River before and after 7 days of settling, by Jeff Hecht:

[](https://i.publiclab.org/system/images/photos/000/001/732/original/charles-river.png)

However, most research in Public Lab to date has focused on oil spectroscopy -- attempting to identify petroleum residue in sediments. Read on to learn more!

oil fluorescence

Oil samples

To measure oil, we have been attempting to illuminate oil samples with UV flashlights and green lasers, which can make some oils fluoresce.

...more soon...