Does anyone know the part numbers for the infrared LED and photodiodes used to measure turbidity?
I found these two IR LEDs on DigiKey. Both are clear with 5.00mm diameter. Is it one of these?
- WP7113SECK Orange 605nm LED Indication - Discrete 2.1V Radial
- WP7113SEC Orange 601nm LED Indication - Discrete 2V Radial
I’m unable to find a photodiode that can detect in this range.
I wonder if the Pioreactor uses the recommendation in the eVOLVER paper to measure at OD900 instead of OD600?
Based on previous work, optical density measurements in a bioreactor can be measured with a simple 900 nm infrared (IR) LED and photodiode pair. There are two practical benefits of using 900 nm scattered light instead of the classic OD600. First, at 900 nm, turbidity/optical density measurements are less dependent on the absorbance spectrum of the media, meaning calibration is required less frequently before each experiment. Second, wavelengths in the visible range are preserved for light induction and colorimetric assays.
There are many IR LEDs and photodiodes that operate in the 900nm wavelength range.
Thank you, Pioreactor community!
Intensity vs Wavelength for the WP7113SEC LED.
