Attempt to build DIY Microvolume Spectrophotometers or Fluorospectrometers to quantitate micro-volumes of sample.
The NanoDrop products 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. Let's try.
To start simple, two approaches are tested, one using an LED and a photo sensor. The second, more advanced, using a DIY spectrometer.
- Turbidity measurement
- Spectral data and purity analysis
- Measure nucleic acid, protein and colorimetric assays
- Microvolume fluorescence measurements
Now the NanoDrop principle seems to be patented (patent US6628382 and US6809826). However there are many similar products on the market under the term of "Microvolume Spectrophotometers"...? Doesn't matter anyways if you just build one for your own use.
A flat head LED and a flat head photo diode are put together, a drop of liquid in between - this is it. Maybe add a screw to set the distance between the light source and the sensor. A small arduino can measure the light sensor and send the data to the computer via USB.
High performance LEDs can replace expensive light source and filters for excitation.
More advanced version based on a DIY spectrometer using a DVD-R optical diffraction
grating and a USB webcam as described by PublicLab. Use the excellent online software workbench to analyse data - http://spectralworkbench.org/ .