AOAC 2018 Methods

for State Medical Cannabis Testing Programs 1 are recommended for sampling). Solid samples, such as dried plants and Cannabis resins are powdered using laboratory blender to obtain material with particle size ≤ 1 mm and stored at ambient conditions. It is recommended to use cryogenic grinding with liquid nitrogen to obtain homogenous material and minimize losses of analytes. In such case, homogenized samples must be stored at -70°C. Liquid samples, such as Cannabis tinctures and oils are briefly shaken and stored at –4°C. (b) Extraction Procedure (Dried Plant Materials). 1. Weigh 0.50 ± 0.01 g of a thoroughly homogenized sample into a 50-mL centrifuge tube. 2. Add 20 mL of EtOH, briefly hand-shake/vortex and then shake for 30 minutes using a horizontal shaker set at approximately 250 rpm. 3. Centrifuge the tube at >3000 g for 5 minutes and filter the supernatant through filter paper into a 50-mL volumetric flask. 4. Transfer the sample material back into the 50-mL tube and repeat steps 2 and 3 Note: Collect the supernatant from second extraction into the same 50-mL volumetric flask. 5. Dilute the flask to volume with EtOH. 6. Filter 3-mL aliquot of the extract using plastic syringe fitted with a 0.22 µm PFTE syringe filer into a 15-mL centrifuge tube. 7. Perform 10-fold and 100-fold dilution of the extract with MeOH in 10-mL volumetric flasks. Note: Higher dilution factors can be employed if required. 8. Transfer aliquots of the original extract and diluted extracts into 2-mL amber LC vials, cap and briefly vortex to mix. 9. Analyze by LC-DAD(MS) (c) Dilution Procedure (Concentrates, such as Resins and Tinctures) 1. Weigh 0.05 ± 0.01 g of a thoroughly homogenized sample into a 25-mL volumetric flask. 2. Add approximately 20 mL of EtOH and briefly hand-shake until the sample is dissolved. Dilute the flask to volume with EtOH. Note: Sonication may be used to support dissolution of the sample. 3. Filter 3-mL aliquot of the extract using plastic syringe fitted with a 0.22 µm PFTE syringe filter into a 15-mL centrifuge tube. 4. Perform 10-fold, 100-fold and 1000-fold dilution of the extract with MeOH in 10-mL volumetric flasks. Note: Higher dilution factors can be employed if required. 5. Transfer aliquots of the original extract and diluted extracts into 2-mL amber LC vials, cap and briefly vortex to mix. 6. Analyze by LC-DAD(MS).

1 Guidance for State Medical Cannabis Testing Programs. Association of Public Health Laboratories 2016 (https://www.aphl.org/aboutAPHL/publications/Documents/EH-Guide-State-Med-Cannabis-052016.pdf).