HPLC (High Pressure Liquid Chromatography) is the gold standard for potency analysis. It is the standard used in every certified testing laboratory worldwide.
What does HPLC stand for and why is it the only method used by professionals?
HPLC stands for high pressure liquid chromatography. HPLC separates liquid molecules from one another in the liquid phase under high pressures. The Cannabis/hemp sample must be extracted into the liquid phase prior to injecting the sample into the HPLC system. High pressure is needed because the HPLC column (which performs the separation) has a very small particle size (less Than 3 microns) and a very large surface area which provides the resolution necessary to separate the cannabinoids. High pressure liquid chromatography can operate under pressures of up to 9000 psi or higher with a pulseless flow. HPLC is the only method capable of separating, identifying, and quantifying the cannabinoids in a liquid sample mixture.
Other Methods Fall Short
There are low pressure liquid chromatography systems that use a peristaltic pump and can only handle pressure less than 100 psi. Peristaltic pumps by design create pulses in order to deliver the liquid stream. Systems employing these types of pumps are not capable of using HPLC columns and instead use a solid phase extraction cartridge with large particles that vary in size. These systems are incapable of separating cannabinoids and therefore it is impossible to accurately quantify them.
A proper HPLC system for cannabis and/or hemp should incorporate a column with a smaller than 3 micron particle size that are monodispersed. Monodisperse means that all particle sizes are exactly the same when examined under a microscope.
It is also critically important that the temperature of the column is heated above ambient temperature and is accurately controlled. This ensures that the cannabinoid peaks / elute off the column at the same time and in the same order every time. Without this precise control you will get erratic results!
The UV detector must operate with a narrow bandwidth at 228 nm. This can be achieved by a fixed wavelength detector, a variable wavelength detector or a diode array detector. 228 nm wavelength provides the best sensitivity for cannabinoids. UV/LED detectors while being small and stable are not suitable for this application. UV / LED detectors that are not filtered given a broad spectrum of light which is not appropriate for any HPLC system.
Another feature to look for is either an automated injection valve or for high throughput systems, a cooled auto sampler. Manual injectors can work but are not as reproducible as the other two options.
An HPLC cannabis and hemp analyzer should include a solvent degasser. This is important to eliminate potential air from entering the HPLC. If air does enter the HPLC, it will cause bubbles that may lead to erroneous results!
There are two ways to do an HPLC separation. For method development, a gradient system works the best. In a gradient system you use two solvents, increasing the concentration of one will decrease the concentration of the other to enable your cannabinoids to come off the column one by one. Once this method is established, an expert can convert the gradient method to an isocratic method. By doing this, you were using only one mobile phase. Isocratic separations are preferred for a routine, repetitive HPLC, such as cannabinoid and hemp potency analysis. This methodology eliminates the possibility of an inaccurate gradient while providing a more robust method.
How to choose instrument control and data acquisition
Traditionally, laboratory HPLC’s are controlled and data is processed by a sophisticated chromatography data station. These work very well for laboratory HPLC where the operator is a chemist or chromatographer and understands how to program the software and evaluate the data after the chromatographic run. Icon Scientific has introduced a simplistic alternative for the non-technical user. The ANSER is a portable, true HPLC cannabis and hemp potency analyzer. It uses a touchscreen control with pre-programmed entries. This method enables an inexperienced operator to control and obtain cannabinoid potencies without the hassle of programming and analyzing data.
How to determine potency
In order to determine the potency of cannabinoids several steps need to be taken. First, the sample must be extracted from the plant material and be put into a liquid form. While there are many variations of this operation, the most important part is that it is accurate and reproducible. Before injecting your cannabinoid samples, you must inject reference samples from a reliable source in order to calibrate your HPLC. It is necessary to get samples of the cannabinoid that you have interest in analyzing. Once you have calibrated the HPLC with your reference samples, it is time to run your unknown samples. Your unknown samples are compared and analyzed to the reference standards and the software / firmware will provide your potency analysis. The ANSER is easy to use, accurate, reliable and reproducible.
There are four steps necessary for cannabis and hemp potency analysis
- Extract sample into liquid form
- Run reference standards for the cannabinoid of Interest
- Run unknown samples
- Software / firmware will provide the cannabinoid potency analysis
There are many portable potency analyzers claiming to be accurate, sensitive, and reproducible. Portable devices that use spectroscopy without HPLC fall short of being able to provide laboratory quality results that are accurate, sensitive and reproducible.
That is why HPLC is the gold standard for cannabis and hemp potency analysis. It is clear that the ANSER is your best option for a cannabis and hemp potency analyzer.
There are many options available for laboratory-based HPLC, Icon Scientific offers a wide array of choices to configure a customized laboratory system. Icon Scientific has recently introduced the first miniaturized, portable, rugged, and true laboratory HPLC cannabis and hemp potency analyzer.
ICON Scientific, Inc
