Stumbled across this a while ago. Tested it, and it seems to work, though false positives are going to be highly likely.
Original called for the following quantities (but I’ve found it can be scaled easily):
250mg activated charcoal (not necessary in oil analysis).
35mg flower sample.
Procedure is simple, and as I said, quantities can be scaled very easily. As a qualitative analysis there’s no need to accurately control quantities. If we were going to try and validate this method for quantification with some kind of colour chart, then we’d have to be more strict.
- Add NaOH + sample to an apppropriately sized vial.
- Half fill the vial with 91%+ IPA + shake.
- Fill the remainder of the vial with IPA that has been diluted to ~50% with H2O.
- Shake, and wait. Purple indicates CBD.
You may notice two layers form depending on amount of NaOH used - NaOH solution and IPA are poorly miscible. You’ll obviously notice the colour change in the top (IPA) layer where your analytes of interest are present.
Original author suggested the use of activated charcoal to give extra clarity and easier spot the colour change when analysing flower samples, however in my efforts, it only seemed to make it even harder to observe any colour change.
There is obviously the potential for false positives here. I tried testing a relatively pure d9 sample, but it turns out my d9 sample had 20% CBD in it after analysis, so the false positive I believed to see for d9 wasn’t actually a false positive, because there was CBD in the sample.
Left = 99.6% CBD
Right = Distillate sample w/ ~70% THC & ~20% CBD.
Suspected THC dominant Flower sample with activated charcoal. (You can see it didn’t really help the colour in my instance, but that could be because I didn’t stick to the outlined proportions).
Video below showing the start of the gradual change in colour after shaking.
edit: Not sure if embedding of videos is supported here yet. Not sure it’s even necessary. Here’s the link anyway