Testing the (CBD) Water: A Q&A With the Niva Labs’ Kris Marsh
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With its complex matrix and plethora of novel compounds, cannabis is already a tough product to test. But when it’s then processed and poured into a carbonated can, things get even trickier. So how are cannabis labs managing to analyze these bubbly, blunt-like beverages? Well one lab in Oakland, California should know. Widely viewed as a forefront facility for the testing of water-soluble cannabis, the Niva Labs has conducted several of its own studies to test the potency, shelf-life, and stability of cannabis drinks.
Earlier this year, Analytical Cannabis spoke with Niva’s lab director, Kris Marsh, PhD, to discuss these studies. Now, for an original Q&A, we caught up with him to find out the nitty-gritty details of cannabis drink testing.
Leo Bear-McGuinness (LBM): What would you say are the specific challenges when it comes to testing cannabis drinks?
Kris Marsh (KM): Well, that's a good question all around. I think there are a few different kinds of challenges: there’s the potency challenge, which I'll focus on, but there's some other considerations too. So let's just talk about it from the beginning of the process.
Right away, when a client brings me a drink, if it's not in a glass bottle or some kind of glass container, that's already an issue. We had a client that was making water spritzer drinks in cans – and there's all this talk of the can liner being an issue. If they inject or infuse their product with 10 milligrams a can – and let's just say they aim a little high – it's quite possible that by the time it gets to the lab the cannabinoids are already sticking to the sidewalls. And I know that's an issue for consumers, but from a laboratory analytical perspective, the client has to hit, at least in California, plus or minus 10 percent of their stated label claim. So, if the cannabinoid emulsion is already sticking to the side of the can, that may result in a failure here in California. We might be 8.5 milligrams per can, and that's too low. That's not really on the lab side; there's not a whole lot we can do about that. But it is something that we talk to our clients about before they even get here. If they want to do that, we ask them to bring it to us the same day after manufacturing, for example. So, that's one consideration.
Another one is testing the potency, which I'll get into in a second. But I just wanted to make another quick note from the client side; they will often do what we call R&D testing or informational testing prior to a regulatory test in California, to make sure that they are getting that right dose. So, they'll give me their product and we'll test it to make sure it's the concentration they would like it to be. Because we're only going on single replicant testing in California, we have one value oftentimes just to go off of. And what sometimes happens – and what frustrates the hell out of our customers – that work-in product R&D test might have one value that's they're expecting, and when they do the bottling process and they send in one more sample for their compliance testing, maybe it's a different value, for reasons due to natural variation and manufacturing uncertainties and things like that.
So, single replicate testing is kind of a bummer here and we're not quite up to triple replicate yet, but that's another issue. Clients you often hear [say], ‘Oh, labs aren't consistent and every lab’s a little different.’ Well, every lab is a little different, but there's very high uncertainty with that one replicate.
LBM: So how do you go about prepping and testing these drinks?
KM: There's a couple considerations we make when dealing with samples. I guess the first question I think of is, how is it encapsulated? Is it a water-soluble cannabinoid? Is it a nano-emulsion? How do they get the cannabinoid in the drink? And then from there that informs us on how we're actually going to prepare that sample.
Some other questions we ask are, is it carbonated or not carbonated? If it is carbonated, that means we'd like de-gas it; we'd like to put it in a sonicator for 30 minutes. And we want to make sure we get all that carbonation out because it hasn't really shown much effect that I know of on density or the pH. I did a few studies where we de-carbonated some sodas and measured the pH and from the time we started to the end it may have changed 0.1 pH units, maybe. That was an assumption I made early on, that the pH would change greatly if you carbonated the drink, but it actually seems like it doesn't.
[It was the] same with the density; there was this assumption that highly carbonated drinks are maybe a little less dense than a regular drink, which is important when we're doing a potency measurement on the back end. But, again, that does depend on the drink. I have found that it's not really that much different in intensity. But we do carbonate it anyway, we think that's best practice regardless, to try and get the carbonation out there.
So, from the start of the sample prep process, if we have a lot of the drinks we'll combine it, homogenize them, we'll then take an aliquot of that, maybe 50 milliliters or so, and de-gas that in a sonicator for 30 minutes. With pretty much every drink, that's the first part of the prep. We haven't found any drinks for this is not really applicable for, but our main prep process basically involves some kind of liquid extraction.
The main goal in all of these things is to disrupt the stability of the beverage, because you've got the oily cannabinoid inside the aqueous layer. You need to destabilize that in order for you to extract the cannabinoids efficiently. The problem with injecting a beverage on its own is it may not be very stable, there are issues with emulsion – actually the emulsion component – maybe interacting negatively with the column, and that can result in inconsistent analysis. And so what we do is we use a system of salt and organics to disrupt what are usually emulsions; I don't see a whole lot of water based things anymore.
But what we do is we take 10 mils of the homogenized de-gassed beverage, and we combine that with 10 mils of acetonitrile and then we add two grams of sodium chloride, we’ll vortex that for five minutes, and then let it naturally separate on the bench. And then we just take the acetonitrile layer, which is where the cannabinoids have been pulled into – the salt does help change the ionic strength of the aqueous layer, which helps to disrupt the emotion, but it's the organic acetonitrile that's really what destroys any capsulation technology almost immediately. And then, of course, the sodium chloride helps to separate the organic layer back out once we're waiting for it to actually separate out in solution. And then we just take some of that acetonitrile and filter it through a syringe filter and then that's what goes into the HPLC for analysis.
So pretty much every beverage we get, that's the go-to method. And there have been times when we've seen a beverage that's extremely fruity and it's got all these flavorings in it. That can make it difficult to separate out. But, for most of them, that's been pretty much the procedure.
LBM: With regards to the testing, it's pertinent to ask, is it just high-performance liquid chromatography (HPLC) and the standard mass spec stuff when it comes to the actual testing? Or are any other techniques used? For example, I've read about infrared spectroscopy being used to test for potency in cannabis drinks now.
KM: Yeah, that's interesting; I've heard that as well, but we haven't done it here. The standard in the States is becoming UV-HPLC for cannabinoid analysis. People do use LCMS (liquid chromatography-mass spectrometry) and GCMS (gas chromatography-mass spectrometry), but it's not as common. I think the problem with infrared is you have to calibrate it based on the cannabinoid it’s in, and that changes. So if you've got water with a cannabinoid infused and then an emulsion, you have to calibrate your instrument based on the fact that it's in water. If you change to a cola product, which has a much higher optical density, then I don't know if that would read the same way. So you might have to calibrate that. I could be wrong; I don't know as much about it.
Now I have used near-IR before with flower and wax and concentrate and things like that, and you can calibrate that to get it to give you a strikingly accurate read of the THC and CBD composition, but I haven't heard about that for drinks.
LBM: OK, thanks for your perspective. You touched upon the challenges that are unique to some of the ingredients that cannabis drinks can have, such as the fruit flavorings. But what about the cannabinoids themselves? Are there any differences in how CBD drinks and THC-containing drinks are treated when it comes to testing?
KM: In short, yes. I think there is a difference. I'd say the general technique for infusing either is the same all around; you can do it at least a couple different ways. I haven't seen much difference in our lab.
But what I have seen are – and this is less of a scientific comment and more of a social one – there are some CBD brands out here that we've confirmed are simply using the word CBD and the drinks have absolutely no CBD in them. We've tested a few off-the-wall CBD waters, because that's a really big thing here, and for a few of them, there is no zero CBD present. It's just water. I suppose it's possible that the CBD could have been ripped out and stuck to the sidewall. But I've seen really bizarre things because there's nobody checking this stuff right now, it's not regulated heavily.
We had one guy come in; he was convinced he had a patent and that he had come up with a technology to pressurize a vessel filled with water until the CBD, quote unquote, suspended itself. That obviously didn't work at all, but it's funny that people are trying. But I haven't seen anything from a technical perspective.
I think the biggest thing, honestly, is that the THC clients, they will oftentimes go to white label formulators. There's a few in the market, we've worked closely with one called Vertosa in Oakland. So, they’ll contract [Vertosa] out and help them design a really nice stable, formulated, tailored emulsion, because the requirements are so stringent here and there's a lot of risk. But [with] CBD, I don't hear of people engaging those people [like Vertosa] as much; it's probably a very expensive process. And I think most people just think, ‘OK, let’s get a basic emulsifier,’ they'll just mix it up and if they get close to the number they're expecting, then you know, that's fine because there's not a whole lot of oversight right now. So, I think that'll change, but the technology is the same.
LBM: Well, I’m now curious whether there ever was any CBD in the CBD water to begin with or, as you say, was it ripped out through the process? Was there ever a good intention in the first place?
KM: I don't know. It's a buzzword right now. And, you know, it's sort of that placebo effect; if you see something that has CBD on it, [you might think] ‘Oh, it's so wonderful. Oh, man, this is going to change my life and pay off my mortgage.’ And then you drink it, and it's amazing, but it's actually just water. But who’s to tell? I don't know if you've tried CBD, but it can be a significant effect at low doses though you may not feel anything.
LBM: There have been developments since we last spoke, and despite many job losses and cutbacks, it still seems like cannabis drink giants such as Canopy Growth remain very keen on expanding this drinkable market. But I haven't seen a lot of data myself to show the market is increasing a great deal in comparison to, say, the edibles and concentrates markets. So, to put it bluntly, are cannabis drinks worth all this effort when it comes to formulation and testing?
KM: It's a great question. Bottom line, I do think it is worth the effort. I think there is a niche market, just like the mocktail market, but it’s more prevalent, I would say, someplace like here in Los Angeles. I mean, if you've ever been to Brentwood – it's a really nice area of Los Angeles – I think they would do quite well there. But it is a niche thing.
You know, you go to buy one soda and it's like $12. Who buys a $12 soda? I know it's nice and it’s got THC in it, but is it really worth it? Until they get something that's more consumer friendly or price friendly, then I think it's going to continue to be that niche market.
This article originally appeared in Analytical Cannabis' Technologies and Techniques for Cannabis Testing eBook in September 2020.