False positives

Since we use mineral oil in the Oil Testing Kit as a non-fluorescing solvent, I was surprised and concerned to see that some baby oils contain vitamin E additives, as the label of the above-pictured bottle indicates! Some folks have mentioned using baby oil as a widely available source of mineral oil, and although it sometimes has fragrances added, the baby oils I've used do not fluoresce on their own when a 405nm laser is shone through them.

But as we learned from a great poster by co-author Edwin Pena of Seton Hall University:

...vitamins E and A can give you false-positives for PAH contamination when using UV fluorescence to assess presence of PAHs...

My attempt and results

So, as @cfastie had a bottle of Vitamin E enriched baby oil at LEAFFEST 2015, I tried it out -- pictured above. I did not take a spectrum of it, but perhaps Chris will. In any case, there's clear and relatively bright visible fluorescence (I was wearing yellow glasses and did not look at it directly, no worries!).

Questions and next steps

OTK users should know that they have to check baby oil for fluorescence before using it as a solvent to dilute samples.