Jessica McKeil   |   February 26, 2021

The Evolution of Extraction: Leaving Legacy Chromatography Behind

Cannabis extraction technologies today are a world away from the crude methods used only a few decades ago.
Jessica McKeil is a cannabis writer based in British Columbia, Canada. She has a passion for cannabis tech and scientific breakthroughs, which has led her to work with some of the industry's biggest brands. She is the owner and lead-writer…

Extraction tech has moved from backyards into laboratories to deliver an increasing variety and purity of concentrates, from distillates to high-terpene, full-spectrum extracts (HTFSE).

How has cannabis extraction technology changed over the years to reach this point? Commercial producers have adopted methods originally developed within scientific research facilities. The same technologies used to explore the different constituents of cannabis in a 1975 paper published in the Journal of Chromatography have transformed and improved to produce concentrates en mass.

As the cannabis world moves legacy technologies in cannabis extraction, here is a look at where the sector is going, from advances in chromatography to solvent-based methods.

Moving Beyond Legacy Extraction Technologies

The big three legacy extraction methods include hydrocarbon, CO2, and ethanol extraction. There are pros and cons to each of these extraction technologies, including initial capital investment, material safety concerns, throughput capability, and final product options.

Many larger companies are turning to chromatography thanks to the growing demand for clean, ultra-pure extractions of isolated cannabinoids. The cannabis sector is very familiar with gas and liquid chromatography for testing cannabinoids, terpenes, and contaminates; the technologies’ move into extraction is a relatively new one.

New advances in liquid chromatography and a boom in demand for pharmaceutical-grade, cannabis-derived compounds have meant several leading extractors made the leap. The technology is still mostly out of reach for most small to medium-size producers, but the costs are rapidly coming down.

A few of the most notable evolutions in chromatography, helping to move it out of the testing sector and into extraction, are reversed-phase chromatography and centrifugal partition chromatography.

●      Reversed-Phase Chromatography

Reversed-phase chromatography is one evolution in chromatography that is now used widely as a tool for THC remediation of hemp extractions. If normal-phase chromatography can separate compounds with different molecular polarities, reverse-phase is useful for separating similar hydrophobicities (like THC and CBD).

Reversed-phase chromatography relies on silica, water, and ethanol as solvents. Biotage is one company currently providing THC remediation services with reversed-phase chromatography.

●      Centrifugal Partition Chromatography (CPC)

This relatively novel extraction method, suitable for pharmaceutical-grade products, operates using traditional column chromatography methodology. But instead of a solid phase, CPC uses two liquid phases: One is stationary, and one is mobile.

As explained by Nature, "the stationary phase is actually a liquid spun around to stay in one place while another liquid moves through the column. Just like oil and water, the two liquid phases don't mix."

This is suitable for precision cannabinoid extraction. According to Nature, "with a big enough column — plus an array of liquid solvents to choose from — chemists can isolate just about any chemical component from a complex extract at purities of 99 percent or more." Gilson Applications Laboratory is one such company currently marketing its CPC technology to the CBD industry.

Non-Chromatography Extraction Solutions

Yet, even with the advances in chromatography tech, the equipment's price point still puts it out of reach for most startups. This means there is a growing movement to improve on current extraction technologies.

Precision Extraction Technologies has recently launched its T-SEP separation process, which it promises is "significantly more cost-effective than chromatography, is just as effective, and removes over 99% of THC."

The T-SEP process (basically a THC separation process) functions with a specialized blend of solvents to create a liquid-liquid separation in a three-cycle wash. Advertised to have a meager operational cost ($3.50/liter) and high output (seven liters per 60-minute cycle time), the T-SEP is quite literally giving many legacy extraction technologies a run for their money.

Another alternative for cannabinoid separation is the Affinity purification system developed by Sixth Wave. Using molecularly imprinted polymer beads, or MIPs, and an ethanol solvent wash, the Affinity system captures target cannabinoids (like THC and CBD) much more efficiently than any current chromatography equipment.

Another benefit over legacy chromatography? The Affinity system works with crude extracts at no detriment to the final product or the equipment's lifespan.

Advances in Chromatography and Beyond

Chromatography is rapidly becoming a tool for extractors, and not just for the testing and analytics sector. For pharmaceutical applications, it offers a level of precision unparalleled in the current crude extraction marketplace. Even with the new advances in chromatography, the technology remains pricey with a low throughput capacity.

Filling the gap for small to medium-scale extractors comes several new non-chromatography solutions. These technologies, like the T-SEP and Affinity, are still reliant on solvents but drastically improve yields, purity, and, most importantly, the return on investment.

 

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