I wanted to run through the Oil Test Kit again and see if i could improve my results. So, I started from scratch built a new cuvette holder (this one included the light-blocking flap, cool!) and a new spectrometer.
In this session, besides the mineral oil, I only scanned two concentrations of diesel, and crude oil, but i scanned each of them 6 times and kept the most similar scans in the sets below:
Crude Oil (3 drops in a cuvette of mineral oil)
Crude Oil (full strength):
Again, as I had the first time using the OTK, I deepened the slot in the cuvette holder where the fluorescence shines out to be read by the spectrometer. This slot needs to be open lower to better line up with the spectrometer slit.
Getting good reads of spectra seems to require continuous holding/adjusting/positioning of the cuvette holder in relation to the spectrometer. I'm wondering if other people had this experience.