A laboratory may report cannabinoid content per gram of a product even though its instrument measures the concentration of a prepared liquid. Meng and colleagues described that distinction in a liquid chromatography–tandem mass spectrometry method applied to commercial hemp products.
The researchers weighed product portions and added extraction solvent before analysis. The calibration solutions contained known concentrations in nanograms per milliliter. Converting a result for the prepared solution to a result for the original product requires the sample mass, preparation volume and any further dilution.
An instrument calibration range therefore does not give the same numerical range for every product sample. A review of a reported potency should check the calculation and the units alongside the analytical method.