What I want to do
I want to be able to grade oils from light to heavy. I'm going to use a means of UV Fluorescence with a 405nm laser pointer. I'll look at the emission spectra and see if I get a shift of the spectra's peak from green to blue as I move from light to heavy oils. My goal is to replicate a UV Fluorescence technique used in UV LIDAR research.
- Can I replicate the location of emission spectra from a 337nm Nitrogen laser?
- Can I see peak transition in oil grades from light to heavy oils?
- what about motor oils?
- can I distinguish diesel from crude?
My attempt and results
The target oils were things I could find nearby-- a few grades of motor oil, some gear oil, crude oil from North Dakota, and deisel fuel. The idea is lighter oils should have a greener peak, and heavier ones a blue peak.
I started with a rectangular cuvette that @warren sent me and filled it with 1ml of mineral oil.
I determined concentration by adding single drops of the target oils.
do the different solutions have the same peaks?
These different concentration spectra seem to have similar peaks between 1-3nm apart.
the higher concentrations gave me a spectra with a clear cutoff, as if I saturated the image. Is this correct? I want to trust the lower intensity spectra more. should I?
Do I see a shift from green to blue as the oil gets lighter?
Will the heavier 80W-90 have a more blue peak than the 20W-50?
- 5W-30 has a peak at 444nm
- 20W-50 at 436-8nm
- 80W-90 at 432-435nm
Well, they seem to roughly follow the blue shift pattern
2-cycle is unlabeled, and so its grade isn't known. but it has a peak at 445
Crude Oil & Diesel
I see 10nm between North Dakota crude and Diesel. The North Dakota crude is dissolved 1 droplet in 2ml of mineral oil, the diesel is undiluted, I am comparing them at similar fluorescences, not concentrations.
Is that good? I'm not really sure. it seems like less of a gap than between different grades of crude.
Questions and next steps
I need people to replicate this experiment.
Hypotheses: 1) by varying the concentration of the target oil to get a lower, less blown out spectrum. true or not?