History/ What is chromatography?
Chromatography is a laboratory technique used to separate compounds from a mixture in order to purify or identify them. The science of chromatography originated over 100 years ago. Chromatography is a rapid and efficient separation technique. Chromatography was first used primarily for the separation of plant pigments such as chlorophyll and carotenoids. Mikhail Tsvat was the first scientist to use chromatography. He separated plant pigments into bands of color by injecting plant extracts mixed with petroleum into a glass column that had calcium carbonate in it. As the liquid passes through the column, bands of color were separated. This enabled them to identify the compounds of the plant. Through the beginning of the 20th century, “color writing” or chromatography was used to separate plant pigments such as chlorophyll (green) and carotenoid (orange/yellow). By 1930, scientists had figured out they could use these techniques for other separation processes and chemical analysis, especially in biochemistry.
Liquid chromatography
In 1952, Martin and synge won the Nobel Prize for their invention of partition chromatography. This was the basis for liquid chromatography. High pressure liquid chromatography (HPLC) has two phases, a stationary and a mobile phase. The packing material, typically called a resin is referred to as a stationary phase because the resin remains fixed in the column. The mobile phase, as it sounds, moves. The reservoir holds the solvent which is referred to as the mobile phase. The mobile phase is pumped through the column with the HPLC pump. The sample is separated based on the resonance time inside the column with the output monitored by a detector, usually a UV detector which creates a chromatogram. High pressure liquid chromatography is the most popular testing method. HPLC is the best method for cannabis and hemp potency testing because it provides the most accurate, consistent analysis.
What is required to perfect a chromatographic separation?
In order to perfect a chromatographic separation, the peaks which are components of the mixture need to be completely separated or resolved from closely eluting compounds.
An ideal high pressure liquid chromatography system must consist of the following components. Since the sample goes in the injector, we will start there. The injector should be automated with a fixed loop. This will provide consistent injection volume. The mobile phase should be degassed with an online degasser assuring that the pump is only pumping liquid without air bubbles.
The HPLC pump should be a two piston high pressure HPLC pump capable delivering pulseless flow at the flow rate needed for the application. Typical HPLC pumps can handle up to about 600 bar of back pressure. This is important because the HPLC column should have a uniform size particle (solid phase) which should be less than three microns in size. This ensures the highest resolution, best sensitivity, and reproducibility of chromatograms.
Another critical factor is making sure you have a column heater. A column heater allows the column to run at the same temperature every time. This assures run to run reproducibility and consistent chromatograms. If the column temperature varies, retention times change possibly leading to inaccurate identification of peaks and their quantification.
The UV detector for cannabis and hemp should be focused at 228 nm. Unfiltered UV LED detectors are not able to give quantitative results because they are looking at broad spectrum UV data, all of which is above the maximum absorption of cannabinoids, which is at 228 nm.
In conclusion…
Icon Scientific’s ANSER is an analytical grade HPLC. HPLC is the gold standard for cannabis and hemp potency testing and is the technique used in certified contract laboratories.
The ANSER is extremely portable and ruggedized. The ANSER is a purpose built, simplistic, user-friendly potency testing solution for cannabis and hemp. The ANSER allows you to determine harvest time, potency and safety. This is critically important whether you are a researcher, farmer, processor, government agency, product developer, or work in law enforcement. The ANSER is a true miniaturized HPLC. It is a turn-key design intended to be used by non-chemist and non-chromatographers.
Call or visit our website for more specs and details. Icon Scientific offers a full complement of HPLC equipment as well as CPC, CCC, flash chromatography, a non-destructive cannabis extraction system, and a process scale purification system.
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