The detection of pesticides in cannabis has been a challenge.
There are many pesticides that are used in commercial cannabis grow operations to kill the pests that thrive on the plants and in greenhouses. These chemicals are toxic to humans so confirming their absence from cannabis products is crucial. A majority of states require labs to test for an average of 18 different pesticides. Testing for pesticides is one of the more problematic analyses, resulting in the need for two different instruments. For a majority of pesticides, liquid chromatography mass spectrometry (LCMS) is acceptable and operates much like HPLC, but utilizes a different detector and sample preparation. Pesticides that do not ionize well in an LCMS source require the use of a gas chromatography-mass spectrometry (GCMS) instrument. The principles of HLPC still apply – you inject a sample, separate it on a column, and detect with some detector. However, in this case, a gas (typically helium) is used to carry the sample.
For GCMS analysis, Cannalytics uses the Shimadzu GCMS-QP2020 with HS-20 Headspace Autosampler. This instrument is designed with enhanced instrument functionality, analysis software, databases, and a sample introduction system. It utilizes a single quadrupole mass spectrometer will help maximize the capabilities of your laboratory. The HS-20 Headspace Autosampler will also be used for residual solvent testing
Sample preparation for LC-MS/MS systems usually requires a QuEChERS sample preparation method. The QuEChERS acronym stands for Quick, Easy, Cheap, Effective, Rugged, and Safe. The method involves sample extraction and cleanup stages. An example of the sample extraction stage. The cleanup stage requires utilizing an aliquot of the extract’s supernatant and adding a dispersive solid phase extraction (dSPE) material followed by shaking and centrifuging before injection in the instrumentation.
For GCMS, the process is the same using a QuEChERS sample preparation.