Public Lab Research note

DIY Micro Volume Spectrophotometer

by gaudi |

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Attempt to build DIY Microvolume Spectrophotometers or Fluorospectrometers to quantitate micro-volumes of sample. Commercial Products like the NanoDrop™ are very popular in scientific labs. The measurement principle of holding a drop between two points - the light source and the sensor - allows to measure samples as small as 0.5µL up to 2µL micro volume without a cuvette. The simple basic principle should be perfect for DIY lab equipment and goes perfectly well with the PublicLab spectrometer concept and SpectraWorkbench software.

So far I built two prototypes from laser cut, black acrylic with mainly a webcam a DVD grating and a mirror inside. The results are promising for measuring absorption spectrum of liquid in the visible. See here for drawing and pictures:

Next steps: I plan to refine some details, hold a workshop at HackteriaLab 2014, document the assembling and upload it together with the design files. An other goal could be to try to measure at lower wavelength (like 260, 280 nm) to quantify DNA and protein. As the lower limit of the DIY spectrometer seems to be around 350 nm I consider using a potodiode rather than a webcam. Not sure on what "transparent" materials to use yet.

As an active member of International Network for building DIY generic lab equipment and art, I (GaudiLabs, am experimenting with various DIY lab equipment.

Update: The website is updated with a new version of a laser cut device now called OpenDrop. The files are on GitHub and you are welcome to try. Thank you for all the valuable comments.

spectrometer nanometer sampling nano-drop


this is super rad! I was bummed when I saw that the nanodrop was patented, so I looked at the patents. There are two earlier devices though:

Nathan McCorkle linked to a teardown of a commercial nanodrop:

an alternate to the droplet appears to be an aperture that fills with liquid via surface tension. here is a patent for such a device designed to replace cuvettes in spectrophotometers:

this is a surface tension technique for spreading out a sample between two plates:

Nathan McCorkle shared some links for these From the PLOTS-Spectrometry List: Mar 21 they're making the beam splitters with photolithography, but laser-cutting the pattern into the double-sided sticky-tape cuvette I posted yesterday might be interesting:

$0.15 Microfluidic Cuvette made with acrylic and sticky tape

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Very nice.
I suspect that the limitation on accessible wavelengths is due to UV due to absorbance by the plastic optics and will not be improved by using a photodiode array. Starna cells (, a manufacturer of optical cells) only recommends optical glass down to 334 nm. They have a special glass that they claim can be used down to 320 nm. Below that, you need to use quartz. Typically, manufaturers of uv capable spectrometers get around the absorbance issues by using metal mirrors and reflection gratings (instead of transmission gratings, like the piece of dvd). Nice job.

Great post, and great comments too. Very informative! Thanks.

One of the best experiences of my time at university when I have had the chance to do a internship at and learn a lot of things like microplate washers, microvolume spectrometers, detection technology or level measurement systems. During this period I have learned more about this then in all time studying

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