Cannabidiol (CBD), a non-psychoactive cannabinoid, has become a focus of research due to its beneficial effect in many areas, i. e. medicine, cosmetic and food industry. The depletion of tetrahydrocannabinol (THC) or purification of other cannabinoids from CBD rich samples is a challenging task due to their similar chemical structure and physical properties. The separation of two substances characterized by close retention times, like several cannabinoids, is one of the largest challenges in HPLC. There are many strategies to overcome the coelution issue, for example changing the flowrate, the solvent gradient and/or the column bed length. When decreasing the flowrate and changing the gradient do not result in separation of the target peaks, a longer column bed length might be the solution. Recycling chromatography could be an interesting alternative strategy to increase the column bed length. This process enables an equivalent separation capacity of a long column using one or two identical short columns and a valve. In the one column system (close loop recycling), the eluted target peaks are re-injected in the same column through the pump. In a two column system (alternate pumping recycling), a 2-position valve is placed between the two columns and, by the switch, the eluted target peak from one column is re-injected into the second column without passing through the pump. In both cases a recycling circuit is formed, which can be repeated several times until deisred separation is achieved. [1,2] In this work, the CBD purification was achieved by using an optimization of the alternative pumping recycling system. An additional UV detector was added between the two columns to monitor the process in real time, which enables the determination of the recycling parameters in one run. The determined settings were used for an automatized separation of CBD from other cannabinoids by switching the peaks between the two columns. The results from the upgraded two columns recycling system, show how recycling chromatography presents a cheaper, faster, greener, and more automatized technique to obtain pure CBD from Cannabis sample.
Faster and automatized CBD purification by recycling chromatography
Greta Compagnin;Martina Catani;Alberto Cavazzini;Simona Felletti
2023
Abstract
Cannabidiol (CBD), a non-psychoactive cannabinoid, has become a focus of research due to its beneficial effect in many areas, i. e. medicine, cosmetic and food industry. The depletion of tetrahydrocannabinol (THC) or purification of other cannabinoids from CBD rich samples is a challenging task due to their similar chemical structure and physical properties. The separation of two substances characterized by close retention times, like several cannabinoids, is one of the largest challenges in HPLC. There are many strategies to overcome the coelution issue, for example changing the flowrate, the solvent gradient and/or the column bed length. When decreasing the flowrate and changing the gradient do not result in separation of the target peaks, a longer column bed length might be the solution. Recycling chromatography could be an interesting alternative strategy to increase the column bed length. This process enables an equivalent separation capacity of a long column using one or two identical short columns and a valve. In the one column system (close loop recycling), the eluted target peaks are re-injected in the same column through the pump. In a two column system (alternate pumping recycling), a 2-position valve is placed between the two columns and, by the switch, the eluted target peak from one column is re-injected into the second column without passing through the pump. In both cases a recycling circuit is formed, which can be repeated several times until deisred separation is achieved. [1,2] In this work, the CBD purification was achieved by using an optimization of the alternative pumping recycling system. An additional UV detector was added between the two columns to monitor the process in real time, which enables the determination of the recycling parameters in one run. The determined settings were used for an automatized separation of CBD from other cannabinoids by switching the peaks between the two columns. The results from the upgraded two columns recycling system, show how recycling chromatography presents a cheaper, faster, greener, and more automatized technique to obtain pure CBD from Cannabis sample.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
