Purpl Tester -- Anyone have experience?

Anyone used the Purpl tester?

I’d like to use it to ‘pre-test’ large, multi-million pound lots of bio before I pay a lab for potency analytics on 100+ samples.

I understand homogenization is required and you should take an average of ~5 tests.

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Is it a refined Beam/Duquenois test? How do they standardize the test samples for accuracy?


We have one but never got to use it. Over a year ago I read somewhere that the lowest limit of quantification for thc was 0.5% so we never got to it because we were trying to test for 0.3% thc at the time.

Interested in selling it?

From what I hear, they work great out of the box, but the accuracy quickly declines.

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You should hire a guy with a trailer full of cannabis testing equipment and is very discrete

Don’t waste your money on Purpl if the results matter financially to you.

Buy a used GC, SRI, Agilent, something already working, pop that sumbich in a trailer with a bunch of 70 duro pads and call it a day


Yes. Whats your offer? We are located in CO and can ship it.

It looks like a colorimetric test? If it is, I greatly doubt the accuracy. They were the first rudimentary tests for humates, and are laughably inaccurate compared to modern methods.

If it is not, I would love to see their testing methodology.


We had one. According to the purple pro everything we grew should have tested 25-30% THC. It didn’t haha.

I have my doubts about the accuracy and precision of their methodology and I really don’t think it’s even accurate enough to use as an estimate. If I wanted to do some small scale, fairly quick test of potency, I would probably go with Orange Photonics over this.


No, just simple NIR Spectroscopy, a modern method. Really nothing crazy to it though, just measures absorbance — it’s the “correlation with concentration” that can make things tricky . HPLC/ GC testing is more accurate.


I think the main interest of such tools is for traders of bulk herb or concentrates. To ensure onsite that what one is buying is CBD or THC. The old one that I’ve seen performing some years ago where not able to do this consistantly. But this last week end, I was demoed a new portable one, which actually could tell if sample was thc or cbd hash.

I had the idea it would be very convenient for breeders, but the detection limit may actually be too high.


If they could get a similar size sample with the same moisture content, Beam or Duquenois tests could work. It’s getting standardized sample input that prevents them from being accurate.

Could always go for a orange photonics. They are like 5-6x the cost though.

Purpl advertises +/- 2% accuracy. I merely want to know if a lot of bio advertised as ~10% is actually in that ballpark before I pull homogenized samples every 10k lbs and send them off to a real analytical lab.

I’ve also seen the thing in action. It’s not reliable.


my experience with the purpl is that it can say if there is thc or cbd present, but the downfall of the measurement is that it’s just a couple photographs and can’t tell you what’s INSIDE your sample - just the surface contents.

wildly random feeling outputs sometimes.

Even if that was 2% absolute accuracy and not relative, we were seeing a 10% absolute difference from what the purple pro read vs what our state licensed compliance labs were testing at and I trust the lab we work with quite a bit (their potency values fall in line with our estimated extraction efficiency and output from distillation - all within a few percentage points of error of course).

It’s just not a piece of equipment I would ever want to recommend to put any stock in its output from my own personal experience.

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get an sri 310


I was testing some old hemp material I was using for RnD and my results showed high 20s and even 30% THC at one point. My material was actually around maybe 7% CBD. I tried contacting their support team, but I never heard back. I personally would recommend the SRI 310C instead.