Tag Archives: concentration

The Nerd Perspective

Detecting the Undetectable

By Amanda Rigdon

In my last column, I took a refreshing step out of the weeds of the specifics behind cannabis analyses and took a broader, less technical look at the cannabis industry. I had envisioned The Nerd Perspective being filled with profound insights that I have had in the cannabis industry, but I have realized that if I restricted this column to insights most would consider profound…well…there would not be many articles. So in this article, I want to share an insight with you, but not one that is earth shattering. Instead, I want to talk about a simple concept in a way that might help you think a little differently about the results your lab generates, the results you have to pay for or even the results printed on a cannabis product you might purchase.

This article is all about the simple concept of concentration – the expression of how much of something there is in relation to something else. We use expressions of concentration all the time – calories per serving, percent alcohol in beer, even poll results in the presidential election circus. Cannabis is not excluded from our flippant use of concentration terms – percent cannabinoid content, parts-per-million (ppm) residual solvents, and parts-per-billion (ppb) pesticides. Most of us know the definition of percent, ppm, and ppb, and we use these terms all the time when discussing cannabis analytical methods. During my career in analytical chemistry, it has occurred to me that parts per billion is a really infinitesimal amount…I know that intellectually, but I have never tried to actually visualize it. So being the nerd that I am, I went about comparing these often-used concentration terms visually in my kitchen.

I started by preparing a 1% solution of food coloring paste in water. This was accomplished by weighing out 5g of the food coloring and dissolving it into 500mL of water (about one teaspoon into a pint). The resulting solution was so dark it was almost black:


The picture above expresses the low end of what we care about in terms of cannabinoid concentration and a pretty normal value for a high-concentration terpene in cannabis.

I then took one teaspoon of that mixture and dissolved it into 1.32 gallons of water (5mL into 5000mL), resulting in a 10ppm solution of green food coloring in water:


I did not expect the resulting solution to be so light colored given the almost-black starting solution, but I did dilute the solution one thousand times. To put this into perspective, 10ppm is well above many state regulatory levels for benzene in a cannabis concentrate.

I then took one teaspoon of the almost-colorless 10ppm solution and dissolved that into another 1.32 gallons of water, resulting in a very boring-looking 10ppb solution of green food coloring in water:


Obviously, since I diluted the almost-colorless 10ppm solution a thousand times, the green food coloring cannot be seen in the picture above. As a reference, 10ppb is on the low end of some regulations for pesticides in food matrices, including – possibly – cannabis. I know the above picture is not really very compelling, so let’s think in terms of mass. The picture above shows eleven pounds of water. That eleven pounds of water contains 50 micrograms of food coloring…the weight of a single grain of sand.

To expand on the mass idea, let’s take a look at the total mass of cannabis sold legally in Colorado in 2015 – all 251,469 pounds of it. To express just how staggeringly small the figure of 10ppb is, if we assume that all of that cannabis was contaminated with 10ppb of abamectin, the total mass of abamectin in that huge amount of cannabis would be just 1.143g – less than half the mass of a penny.

To me, that is an extremely compelling picture. The fact is there are instruments available that can measure such infinitesimal concentrations. What’s more, these tiny concentrations can be measured in the presence of relatively massive amounts of other compounds – cannabinoids, terpenes, sugars, fats – that are always present in any given cannabis sample. The point I’d like to make is that the accurate measurement of trace amounts of cannabis contaminants including pesticides and residual solvents is an astounding feat that borders on magical. This feat is not magic though. It requires extremely delicate instrumentation, ultra-pure reagents, expert analysts, and labor-intensive sample preparation. It is far from trivial, and unlike magic, requires a large investment on the part of the laboratories performing this feat of science. Other industries have embraced this reality, and the cannabis industry is well on its way toward that end…hopefully this article will help put the job of the cannabis analytical lab into perspective.

Colorado Rule Changes Increase Costs for Edibles Producers

By Aaron G. Biros
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Cannabis processors and dispensaries in Colorado were hit with new rule changes over the weekend, going into effect on October 1st. The rule changes affect those producing edibles and dispensaries that sell retail and medical cannabis products.

The universal symbol required on all cannabis products in Colorado
The universal symbol required on all cannabis products in Colorado

As of October 1st, all cannabis edibles must be marked with the universal THC symbol, according to a bulletin posted by the Colorado Department of Revenue’s Marijuana Enforcement Division (MED). Both medical and retail cannabis products require labeling that includes a potency statement and a contaminant testing statement.

The rules also set “sales equivalency requirements” which essentially means a resident or non-resident at least 21 years of age can purchase up to one ounce of cannabis flower or up to 80 ten-milligram servings of THC or 8 grams of concentrate, according to the MED. The packaging must also include: “Contains Marijuana. Keep out of the reach of children.”

The universal symbol printed on products from Love's Oven.
The universal symbol printed on products from Love’s Oven.

It seems that cannabis edible manufacturers have two clear choices for complying with the new rule requiring the THC symbol: They can use a mold to imprint the symbol on their product or they can use edible ink. Peggy Moore, board chair of the Cannabis Business Alliance and owner of Love’s Oven, a Denver-based manufacturer of cannabis baked goods, uses edible ink to mark each individual serving. The printer uses similar technology and ink used to print on m&m’s, according to Moore. “Baked goods are difficult to find a solution for marking them because they are a porous product, not smooth.” Complying with the new rules almost certainly means added costs for processors and edibles producers.

Moore said she updated all of their labels to include the appropriate information in compliance with the rules. “In terms of regulatory compliance, there have been some disparities for labeling and testing requirements between medical and retail cannabis products, however they are coming into alignment now,” says Moore. “The testing statement rule has been in place for some time on the retail side, but now we are seeing this aligned with both medical and retail markets.” This new rule change could be seen as a baby step in making the different markets’ regulations more consistent.

BEST Extractions

Defining BEST Extraction

By John A. Mackay, Ph. D.
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Over the next few months, I would like to walk through a series of articles to cover the number of ways to extract potentially pharmaceutically active compounds from cannabis plants. However, in the first article I would like to review concerns being addressed in state regulations: contamination in concentrates with pesticides, mycotoxins, and residual solvents. The next article will cover the most common extraction with two different modes: CO2 versus hydrocarbons.

Currently, there is a lot of focus on the cannabis strain of hemp. This is defined as having less than 0.3% of THC, (the psychoactive compound). To be clear, the science of extraction is eons old, but the current revitalization is due to new scientific inquiry regarding the applications of the cannabis plant.

I am often asked, “What is the ‘best’ extraction for a natural product?” The BEST extraction? The key to this answer is that you must assume unintended consequences until you can prove that they are at least minimized compared to the intended consequences.

I have a suggestion for you to consider and I look forward to your response to it. I also assume the right to adapt and revise it.

Botanical integrity from seed to shelf

Efficacy of the process beyond efficiency, economics, effectiveness

Safety of people and product

Testing for confirmation at each step of process

The hemp industry has changed significantly over the past few years. Just casually flipping through the channels on television, reading a newspaper or magazine, (on any topic – news, business, sports, food and science) and there is some facet of hemp’s value being examined. The reduction of traditional pulmonary intake (smoking) in the legal marketplace can be tracked by sales of these products in the states where it is legal. The balance of ingestion is drastically tipping toward what might still be considered smoking with vaporizer products as well as toward edible consumables. The ingredients in these products come not from just adding the plant to the formulation, but rather a concentrated mixture. This is the difference between adding a raw vanilla and a teaspoon of vanilla extract. The compound getting the most coverage is cannabidiol (CBD), which is the compound derived from cannabidiolic acid (CBDA). The effects of the other compounds in the plant are being studied as well.

Unintended consequences from the concentration – extraction – are something we need to consider seriously as consumers. The labeled use of “natural” is one that is critical, but can be totally nullified by the unintended contamination in the extraction workflow. Years of making sure the hemp adheres to strict growing environment can be destroyed in seconds with the addition of polycyclic aromatic hydrocarbons (PAH’s) by the use of solvent that has these toxic chemicals in them. These come not through intended consequences, but not knowing the stabilizers and other additives in material being added to these previously pure plants.

What if I pour sour milk on a natural granola for breakfast? What if I use water with high lead or contaminated water to pour over natural coffee grind? Not a great way to start the day, but it is no different than using the most premium hemp and unknowingly adding low grade solvents or adding components from cleaning the surfaces of instruments that come in contact with hemp.

Note that, by definition, we are concentrating the material from the hemp plant. From 4,000 grams, we are getting 400 grams of CBDA if it is 10% by weight (and later converted to CBD). That compound is 10 times more concentrated in a solution. What other compounds are now also 10 times or 5 times or 100 times more concentrated? Maybe no “bad” ones, but how do you know that something else is not also in the mixture?

figure1 extract
Figure 1. With each step of concentration of the green balls, so it could be with other components in the mixture.

This is illustrated in the filtering of green balls in Figure 1. As the green balls become a greater and greater percentage of the solution, it is possible that other compounds like pesticides are also increasing in percentage of the extraction solution. The solution is more concentrated and “simpler” versus all of the other things in the original mixture.

The simple answer is in the testing of the components. The labeling of major compounds is only the beginning of what is on the label that you read. Heavy metals? PAH’s? Residual solvents? Pesticides? Molds? And a long list of other material that could come into the process after the plant left its pristine organic farm. Many studies can be read about slip agents in bags, contamination from workers in the workflow, and other sources of inconsistency.

There are a significant number of companies that I have seen that take this very seriously. New companies are being formed that have safety of product at the top of the list of importance. They are building facilities that are sterile and putting standard operating procedures in place that continually test the product along every step to ensure that they are in compliance.

Figure 2. Science and economics merge when considering all the possible uses of concentrated compounds to final product formulations

Supercritical fluid extraction is GRAS (generally regarded as safe). It is, only as long as the solvent specifications are known, the vendor meets those standards, and the instrument surfaces meet any necessary standards.

Supercritical carbon dioxide is used to clean surfaces of electronics and bones for skin grafts. It is used for the decaffeination of coffee as well as pulling trace amounts of pesticides from soil. It is used to extract antioxidants from krill and the active ingredients from algae as well as oil from core samples deep below the earth. It also extracts the terpenes and CBDA from hemp – as well as possibly anything that has been added to it.

The key take away from this article is to know the BEST extraction.

Botanical integrity from seed to shelf

Efficacy of the process beyond efficiency, economics, effectiveness

Safety of people and product

Testing for confirmation

Taking each of these into consideration will bring the best results for concentrations of hemp products. I hope you can extract the best from your day.