I’m looking into purchasing a cheap uv-vis spectrophotometer but am not affiliated with an institution at the moment given the whole COVID 19 situation. Are there any good recommendations for cheap visible light spectrophotometers that can analyze wavelengths of light on the order of 370nm and are purchasable directly to consumer?

Edit: Budget: $500-700

  • $\begingroup$ yeah, ocean optics are expensive. I've been interested in making a DIY spectrometer for some time but haven't had the chance. It would be significantly cheaper. Unfortunately I can't tell you how easy or reliable they are. $\endgroup$ – Cody Aldaz Apr 18 at 23:41
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    $\begingroup$ Check the Journal of Chemical Education articles. They have plenty of exercises. Also check Vernier. $\endgroup$ – M. Farooq Apr 19 at 1:48
  • $\begingroup$ Unfortunately, I cannot purchase from Vernier because I’m neither from the US or affiliated with an institute that has a vernier account. $\endgroup$ – Thunderbolt114 Apr 19 at 2:21
  • $\begingroup$ They do sell internationally. $\endgroup$ – M. Farooq Apr 19 at 4:18
  • $\begingroup$ CD fragment as a diffraction grating. Cellphone camera to measure light levels. Yee Ha! :-) $\endgroup$ – Russell McMahon Apr 19 at 9:50

Disclaimer: I'm not affiliated with any company

However, Ocean Optics cuvette spectrophotometers are a good choice

This model is used in some undergraduate labs and is good because the cuvette holder is built in (i.e. it doesn't require a fiber optic cable).

As long as the optics don’t get jumbled, the prism detector mechanism work well and reliably for many years, although it says to get it checked each year.

If you're on a tight budget I'd recommend looking at a DIY spectrophotometer. In particular the RasberryPI designs seem relatively simple

The Hackaday website has a blog dedicated to DIY spectrometers.

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    $\begingroup$ Sigh. When will good spectrometers be affordable... I bought my Amadeus spectrometer (based on OceanOptics components) years ago for roughly the same price. $\endgroup$ – Ruslan Apr 19 at 11:55

Good spectrometers in "new, unopened" condition are out of your budget. Their prices start at about 2000 USD. This also includes the spectrometers specifically made for education—like the ones from PASCO (example; they are usually based on Ocean Optics components), and from Ocean Optics themselves (example).

One option for your budget is to buy a used spectrometer like Ocean Optics USB2000. There's quite a number of options on Ebay, including one for 700 USD (example; the link will likely rot soon), and some more on Amazon (example). But note: you should make sure you ask the seller about wavelength range and resolution, as Ocean Optics spectrometers of the same model can be configured with different slits, gratings, detectors and filters.

These are the commercial solutions, with a quality reflection-based diffraction grating, focusing mirrors and a CCD detector. Here's the typical optical bench of an Ocean Optics spectrometer (image source; the rubbed pale-reddish line on the left-hand side is the place where the CCD detector is to be placed):

Ocean Optics optical bench

Another option is to get something from Thunder Optics. I have tried "Mini USB spectrometer", which currently costs about 100 USD. But this one not only has much smaller price than the Ocean Optics spectrometers—inside it's basically a DIY spectrometer: a cheap wobbly transmission grating (secured in a plastic holder to avoid too much wobble), a web camera as the detector, and a fixed thick slit in the thick (1.5 mm) aluminium case. The components are fixed in place with some kind of black glue.

This kind of spectrometer isn't useful for anything but a qualitative* look at relatively bright** sources of light.

Here are two photos of my item ("optical bench" and the slit):

view of the optical bench

view of the slit

* Qualitative, because you can't get raw data from the camera.
** Bright, because the camera has quite low sensitivity, and the optical bench lacking any focusing mirrors reduces light gathering capability.

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  • $\begingroup$ I was looking into Ocean optics spectrometers and it seems like I need auxiliary materials like patch cords, cuvette holders, and a light source? Is there some seller that includes all of these things together? $\endgroup$ – Thunderbolt114 Apr 19 at 18:36
  • $\begingroup$ @Thunderbolt114 do you mean new ones, not used? In that case I suggest trying PASCO Wireless Spectrometer, which already includes 10 cuvettes, built-in light source, and doesn't need any fiber cables. Too bad they don't list the exact price, but you could request a quote. $\endgroup$ – Ruslan Apr 19 at 18:42
  • $\begingroup$ For UV-vis I would greatly recommend a Cary 50 UV-vis spectrophotometer from Agilent or a GBC Cintra if you need a double-beam one. Both quite affordable on ebay and also quite reliable. As for cuvette holders, they are certainly not a major price crux, but for a budget version, you could ideally have one 3d-printed. $\endgroup$ – flippinpippin May 3 at 13:59
  • $\begingroup$ @flippinpippin that's an interesting direction. I didn't even think of "wavelength-at-a-time" scanning spectrometers. Is this Cary 50 still >2000 USD when sold as new (Agilent's website doesn't list a price)? Or should I edit the first sentence of my answer? $\endgroup$ – Ruslan May 3 at 16:44
  • $\begingroup$ Honestly, I have no idea about the official prices, but the Cary 50 is the most basic model, which should be at a reasonable price. Also, it is nothing new really, measuring spectra in time is a common practice for example in actinometry. $\endgroup$ – flippinpippin May 6 at 7:41

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