These questions have to do with certain things that I would like to achieve with DIY spectrometers. The first thing that I want to achieve is to determine the pH of a solution with purple cabbage juice. There is a research paper that tells that the pH could be accurately measured at 533 nm with absorbance values for pH values between 2 and 11, which is a wide range. I was doing some tests in the spectral workbench and noticed that for each wavelength there are 3 values, red, green and blue. Are there some ways to change these values to absorbance measurements? because, in the paper use this unit measurement.
The other thing that I would like to achieve is to determine the dissolved organic carbon (DOC) of a water sample also with a spectrometer. This is a good tool for community science because you need no reagents. The only thing that I don't know if it is possible with DIY spectrometer is to measure in the UV wavelength, because the DOC is measured at 254 nm.
I hope someone have some time to answer these questions.