A hemp extract contains compounds besides the cannabinoids a lab wants to measure. When those co-extracted compounds change the analytical response, standards made in clean solvent can give the wrong relationship between signal and concentration. Matrix-matched calibration starts with a material that resembles the sample and has had the target compounds removed.
Mastellone and colleagues prepared blanks for hemp aerial parts and flowers by repeatedly extracting the target cannabinoids from the plant material. They then added known quantities to make calibration standards. For the commercial CBD oil they used pure coconut oil as the blank, a separate choice for a separate matrix.
The method achieved reported accuracy values from 82% to 118% under its validation conditions. For a new product, the relevant questions are whether the blank has residual target compounds and whether it reproduces the response in that specific sample type.
Mastellone et al., Journal of Chromatography B ยท PubMed record