Liquid Chromatography: Simple LC and HPLC

mass spectrometry
Written by Cara Wietstock

Liquid Chromatography is an analytical chromatographic technique is used when separating ions or molecules of the cannabis plant or downstream products thereof.

Simple Liquid Chromatography

A solvent is used in this process before using the sample solution in a second solid or liquid face to watch how it interacts with specific solutes. A lab technician or chemist will analyze the differences in adsorption, ion-exchange, partitioning, or size. These differences are used to determine the right transit time of the solutes through the column for the mixture components to separated from each other. Simple liquid chromatography consists of a single column that holds a stationary phase in equilibrium with a solvent using a fritted bottom.

Stationary phases of LC include ionic groups on a resin, liquids on an inert solid support, porous inert particles, and solids. These phases are also called ion-exchange, partitioning, size-exclusion, and adsorption. The cannabis that we would like to isolate is loaded onto the top of the column before more solvent is brought into play. The sample mixtures various components will pass through the column at differing rates because of their partitioning behavior between the mobile liquid and stationary phases. The chemical compounds are then separated by collecting portions of the column waste as a function of time.

liquid chromatography

High-Performance Liquid Chromatography

Also called High-Pressure Liquid Chromatography or HPLC, this process has been used in manufacturing many pharmaceutical and biological products, in the medical field, in research, and more. This testing lab and extraction machine is different from simple LC because it relies on pumps to pass the pressurized liquid solvent through the column. It operates at significantly higher pressures since simple LC relies only on the force of gravity to run through the column, they’re also made with smaller sorbent particles.

liquid chromatography

HPLC has superior resolving power for separation as compared to simple LC which is why it is the most popular chromatography technique used in cannabis testing labs today.

About the author

Cara Wietstock

Cara began working in the retail cannabis industry of San Francisco, CA in 2011 and continued in that sector for years. In 2015 she dedicated herself to writing full-time. Her passion for the written word and deep respect for the healing properties of the plant have brought her to Terpenes and Testing magazine. She now helps keep us on the cutting edge of scientific cannabis discovery as the Editor-in-Chief of the print publication.

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