The 2018 Farm Bill, which legalized cannabis with .3% THC or less, or, hemp, in the United States, has created one major regulatory wrinkle: hemp is tough to distinguish from its higher-THC cannabis cousin.
This case of mistaken identity has led to major seizures of hemp crops, including one dispute that wound its way through the courts after Idaho State Police seized about 7,000 pounds of “cannabis plant material” in January 2019 as it was being transported between Oregon and Colorado, passing through Idaho. (Read Cannabis Wire’s coverage of this case.)
In another case, in November 2019, the New York Police Department seized more than 100 pounds of hemp from a wholesaler, originally charging a wholesaler with six felonies before the Brooklyn District Attorney dropped the charges.
The race has begun, from researchers to lawmakers entrepreneurs, in search of solutions. Dmitry Kurouski, an assistant professor of biochemistry and biophysics at the Texas A&M University College of Agriculture and Life Sciences, recently led a study on scanning technology that could prove useful to law enforcement trying to distinguish between plants with low THC and high THC, he told Cannabis Wire.
It could also be a valuable tool for farmers and others in the cannabis industry, he added. One of the biggest headaches facing hemp farmers is around THC content. For example, if a hemp plant tests positive for more than .3% THC, those plants are likely headed for destruction. (While some states have moved toward mitigation plans, still, those plants are not going to provide revenue to the farmers in the short-term.)
This is where a handheld spectrometer could come in, Kurouski said, who mentioned that the catalyst for using the portable scanner was a conversation with his colleague David Baltensperger, professor of soil and crop sciences at the College of Agriculture and Life Sciences, who was familiar with the hemp testing issues faced by both farmers and cops.
Kurouski’s lab typically uses Raman spectroscopy to quickly test plants for various diseases. But, after speaking with Baltensperger, he thought, what if this would work for THC? Or other cannabinoids?
Cannabis Wire had an interview with Kurouski to better understand his team’s research, and what he’s working on next when it comes to cannabinoids.
(This conversation has been lightly edited for clarity.)
Alyson Martin, Cannabis Wire: Tell me more about how you decided to dig in on hemp testing research. I know your colleague played a big role, but what else brought you to the topic?
Dmitry Kurouski, Texas A&M University: Good question. So my group, what we do is we use Raman spectroscopy to look at plants, broadly defined. And primarily what we focus on is diagnostics of plant diseases as well as biotic stresses on plants. By biotic stresses, we typically mean nutrient deficiencies or drought or soil stress.
We are good colleagues and neighbors with David Baltensperger [professor of soil and crop sciences at the College of Agriculture and Life Science], who approached us and proposed to look at hemp and cannabis. We were thrilled because we understood immediately that it’s a very big and important topic, to demonstrate that using noninvasive techniques we can distinguish between hemp and cannabis. We also felt pretty confident and prepared to do this research because we were working on all different groups of plants—on trees, on shrubs, on grasses—for the past two years.So we know how the plant’s fingerprint should look, what we should expect in terms of being careful and not burning the sample. All of these things.
Alyson Martin, Cannabis Wire: Can you describe your methodology? How did you think about how to conduct this research?
Dmitry Kurouski, Texas A&M University: The technique that we developed is called Raman spectroscopy. The name comes from the name of the scientist, C.V. Raman, who reported the first experimental demonstration of evidence of this type of spectroscopy. The theoretical prediction of this event was made in the 19th century. We shine laser light on a sample, using a spectrometer, a very small unit, and we collect light that is scattered off the sample. There will be two types of scattering. One is elastic scattering. In this type of process, photons would not change energy. They will scatter off on the sample with exactly the same energy. In the second type of scattering that we are interested in, photons would inelastically scatter from the sample. Meaning, they would exchange their energies with molecules of a sample, bringing the molecules at a high vibrational state. And the scattered photons, like I said, will have a different energy. And the change in energy will directly depend on the chemical structure and composition of the sample.
If there are carbonyl groups, ketone groups, or there are double bonds, triple bonds, we will see it in the fingerprint that we record. We call this fingerprint a spectrum. So we can directly probe the chemical composition of the sample. What is different between hemp and cannabis is the content of THC. In hemp, it has to be below .3% according to the federal law. If it’s present, it’s clearly detectable in our spectra. So this is the observation or detection of THC in the sample is what the method is based on.
Alyson Martin, Cannabis Wire: How long does this process take to be conducted, from start to finish?
Dmitry Kurouski, Texas A&M University: One second. It only takes one second to get the spectrum. And I want to emphasize that this is non-invasive. It’s nondestructive. We don’t want to do anything to the sample. We don’t have to dry it. We don’t have to spray anything on it, or somehow chemically label it. It’s completely non-invasive, non-destructive, only one second spectrum acquisition, and instantaneously, after this, we get a message on the screen about the prediction of the substance that we analyze.
Alyson Martin, Cannabis Wire: Can you describe any conversations you’ve had with cannabis industry stakeholders, lawmakers, or law enforcement? Obviously, the differentiation between what we know as marijuana versus hemp is a conversation that’s coming up a lot during legislative hearings. Have you had any conversations with people like that about your findings?
Dmitry Kurouski, Texas A&M University: We discussed it along with our friends and collaborators in the state of Colorado. They are very interested in diagnostics of THC, primarily from a perspective of plant breeding, because they test lots of hemp varieties and they’re very interested in identification of all these varieties. To a large extent, cannabis farming is a mess, because most of these varieties were grown in garages by hippies. Of course there are no records of this about breeding, about the origin of any variety. And at the same time, there are more than 900 varieties of cannabis only in the state of Colorado. So it’s a huge amount of plants that are poorly characterized. And to really do farming, people have to plant seeds, monitor how they grow, do lots of analysis, to really develop a specific variety for their needs. And of course, they’re really interested in technology that they could do such analysis, non-invasive and nondestructive. They’re very interested both in identification of cannabis and cannabis varieties, and probing the THC content, because they will want to know when to harvest, what greenhouse conditions they have to choose, like lengths of lighting, water supply and so on. And they’re very interested in this optimization because, of course, property is expensive and all these plants require very special care. Every single plant gets a tube that supplies it with water and overall, it’s a pretty expensive business. So they’re very interested in optimizing it to get the highest THC content they can.
That’s one. Number two: What’s happening in the cannabinoid industry? More people are interested in growing plants that would produce other cannabinoids such as CBD or CBG, for example, rather than plants that produce THCA or THC. And not a surprise because CBG and CBD have fairly unique pharmacological properties. They help treat anxiety. They help treat lots of severe diseases, including insomnia and all of this. And of course, they can be grown in plants and extracted, just like people extract THC, and sold as food supplies. So, many people are interested in using Raman to probe other cannabinoids such as CBD and CPG in plants. Simultaneously, some want to confirm the absence of THC because they want to stay legal. For example, in the state of Texas, now you can grow hemp legally. You have to get a license. And you have to be sure that your hemp plants have THC levels below .3%.
Alyson Martin, Cannabis Wire: Who do you think might be most interested in using this kind of scanner? People in the hemp industry, or law enforcement, because they’re still trying to detect THC?
Dmitry Kurouski, Texas A&M University: To be honest, both. I see strong interest in both law enforcement and hemp breeders and growers and farmers. I received [letters of support from law enforcement] that speak to the interest of law enforcement in these developments.
But like I said, I see a strong interest from plant breeders and farmers in developing this, because for them, this is the front door in plant breeding that can be done non-invasively, nondestructively.
Alyson Martin, Cannabis Wire: Do you plan to do any further research specifically on this hemp scanner? And are you pursuing any private sector opportunities?
Dmitry Kurouski, Texas A&M University: We are interested in developing several components of this scanner. The first is to make it more accurate. We think that accuracy still can be improved. We care about developing a spectroscopic library. In other words, we want to get many, many, many signatures of different hemp and cannabis varieties to make a prediction more accurate in terms of identification of cannabis. We think that’s very important. We also want to improve both signal to noise and accuracy. So there was a big room for improvement.
Alyson Martin, Cannabis Wire: Tell me more about the accuracy of the hemp scanner.
Dmitry Kurouski, Texas A&M University: The current accuracy, or differentiating between different varieties of cannabis, is around 95%. But the accuracy that we want to improve is the quantitative prediction of the THC level in the plant material. For example, someone may wonder whether a plant material has 7.5 or 8.5% THC.
Alyson Martin, Cannabis Wire: What can you share about the CBD scanner you’re working on?
Dmitry Kurouski, Texas A&M University: This a big fish that we’re ready to catch because the industry is moving from THC, or production of cannabis, into production of hemp varieties that are rich in other cannabinoids. And these cannabinoids are very pricey. They have very unique pharmacological properties. And more and more people want to grow hemp enriched by CBD or CBG. Our spectrometer can predict the presence of other cannabinoids in hemp, in plant material. So we know it works and we just sent a paper to Analytical Chemistry that reports on the spectroscopic prediction of other cannabinoids in hemp, in addition to THC.
Alyson Martin, Cannabis Wire: Are you in contact with any regulators or federal agencies about your work?
Dmitry Kurouski, Texas A&M University: We’re interested in approaching the United States Department of Agriculture. They have a program called the National Institute of Food and Agriculture, and this program follows a variety of topics relating to plants and agriculture, ranging from instrumental development to national security to improvement of plant stability. It’s a very broadly defined program and we’re interested in reaching out to them because more and more states are legalizing cannabis and more and more states have changed their laws in terms of hemp. I’m sure that a very serious federal agency like USDA would respond to those new calls and will be able to fund proposals that aim to develop technologies for prediction of cannabinoids in the plants.
Alyson Martin, Cannabis Wire: Let’s return to the law enforcement question. Right now, many police departments struggle with how to distinguish someone hauling a legal hemp crop, and whether someone is transporting something higher in THC content. How could your work on scanners affect law enforcement procedures?
Dmitry Kurouski, Texas A&M University: This problem is enormous in the United States because, if I’m not mistaken, eleven states legalized cannabis, where other states, some of them decriminalized. Some of them still consider cannabis illegal. And the biggest problem is that hemp and cannabis look identical and smell identical. And in the beginning of January, here in Texas, we had a serious, big news story about a hemp driver who was crossing the Texas border. I believe driving from New Mexico. And he was carrying hemp in a truck and troopers stopped the person, and, looking at the plant material, suspected that it was cannabis. And the truck driver spent one month in a jail waiting for the result of forensic expertise. And as he was telling the trooper, it was hemp, so the result was negative. Nevertheless, for the whole month, the person spent it in a jail. Our technology is portable, it can be used directly by a trooper.
