How does one determine Metastable zone width (MSZW)

… without $100,000 lasers?

MSZW with Lasentec.pdf (852.6 KB)

I got quoted $40k by someone who definitely knows what they are doing to determine this for us. I don’t have $40k.

I’ve started reading this stuff but my brain doesn’t seem to be working as well as it used to. Probably because my last formal chemistry training was over half a lifetime ago.

And they’re selling the $100k laser so they obviously think the $100k laser is the best way to do it.

Can’t I just redneck this with some laser pointers and some duct tape or something?


I wonder if you could do this (poorly) with equipment for measuring turbidity. Neat that there’s an actual measurement for this though


Hmm. That does seem like it could be a good way to get a pretty basic yes/no to at least a part of the question.

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I do have a Hanna photometer that does turbidity, I wonder if you could just titrate solvent in until the turbidity hits an inflection point. Going the other way might be more difficult, you’d have to titrate in a solid because obviously you can’t use oversaturated solution until turbidity increases sharply. Maybe if you used really hot solvent and calculated the impact on the bulk solvent temp.

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Sure seems like it. They’re looking at backscatter which is what we are seeing when we notice or measure turbidity (I think).

You should see the size of the spot get bigger for the transmitted light, and the % reflection should go up. I’d imagine the correct laser might depend on material.


I would look into whether any of thr universities near you might be able to do this for cheap


Good point.

Unfortunately, due to Canada’s “legal, but only barely” regulations, any university that wants to do even basic solubility research on cannabinoids needs to have a Cannabis Research license. The queue for those licenses appears to be well over a year long to even get your application looked at.

One semi-local university has one.

That’s who quoted me $40k.



Not sure how much it costs but sounds like thats what your looking for.

Or just use a good flashlight under a jar like us poor plebs.


I did the smart thing and worked out a deal with someone with far more equipment and brains to get the data I need generated.

One can also purchase turbidity sensors for microcontrollers. They would likely do the trick.


I was gonna say, @RockSteady might be a good teacher.


Turns out one can purchase turbidity sensors for your DISHWASHER!

@AlexSiegel; any chance we could use a fraction finder to determine turbidity?

(Surely it’s good for something?!?)

I’d recommend looking into using the dishwasher turbidity sensor

The fraction finder would be a round about way to test turbidity. Peaks vanishing indicates turbidity but the excitation light might get bent into the glass tubing they use.

A turbidity sensor of some kind should probably be part of the fraction finder offering because fraction finders don’t work well in turbid solutions on top of the normal limitations