I'm trying to make a Spectrophotometer to measure solute concentration in the UV C spectrum, specifically I want to measure caffeine concentration which is measured at approximately 270 nm, currently I bought a UV led that claims to emit light between 265-275 nm, and for measuring the light intensity I found this GUVA-S12SD sensor, but as the question says, it only outputs current in relation to the UV index, I don't know if that can be use for my purpose, or if there is a way to calculate Light intensity from the UV index.
If you have any other recommendation for my project, I would be very grateful.
Thanks to everyone.
The linear relationship of the concentration and the absorption (optical density, OD) is " OD= -log(I/I0)=a*b*c", for a low concentration of sample.
The output currents, I0 and I, represent the UV intensity before and after the sample, respectively. In addition, the parameters a, b, and c are absorption coefficient, light path in the sample, and the concentration of your sample.
So you will obtain the OD through the measurements, and to deduce the concentration, you need to know the absorption coefficient "a" of the sample.
The UV-Vis spectrophotometer can measure 200nm, if the integrating sphere is not used. You don't need to buy a diode
Building a piece of equipment to measure absorbance in the UV is not simple. Do you have no other option?
Because the output signal is the electronic current, you have to obtain the dark current "Id" before measuring the currents of reference and sample ( "Ir" and "Is"). Then apply the equation OD= -log(I/I0) for OD calculation, where I0=Ir-Id and I=Is-Id.
Also, put a bandpass filter @270nm after the UV light can control the observed signal only from the absorption at 270nm.
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