Cannabis flower is complex and contains high levels of cannabinoids making it a difficult matrix for trace level pesticide analysis. Methods exist but challenges with analyte detectability remain. Most methods do not significantly reduce cannabinoid content resulting in high ion suppression when liquid chromatography tandem mass spectrometry with electrospray ionization is used. In addition, material is considered dry so a low ratio of plant material to extraction solvent is typically employed resulting in a lowered injection concentration of incurred pesticides.  Extracted sample dilution factors of one hundred have been required to reduce ionization matrix effects to acceptable levels. This makes it challenging to detect pesticides, especially those that do not ionize well. This work optimizes cannabinoids removal so that acceptable detectability and data quality can be achieved. Experimental sample preparation products previously investigated have been optimized for to achieve maximum cannabinoid removal while maintaining the best possible pesticide recovery. Chlorophyll removal was also considered during method development because it can increase instrument fouling.<br/>Multi-residue pesticides were tested, a subset of which were the Oregon regulated compounds. Several combinations of extraction and solid phase extraction were evaluated. Discussion will focus on three cleanup products including a dual layer SPE pass-through cartridge with proprietary sorbents, and EMR lipid blend SPE cartridge also used in the pass-through mode and a zirconia coated silica dispersive solid phase extraction tube. Each was evaluated by gravimetric analysis, volatile coextractives via gas chromatography mass spectrometry, cannabinoid removal and pesticide recovery by liquid chromatography based techniques. Advantages and disadvantages for each proposed method will be discussed.<br/>

Cleaning up cannabinoids and chlorophyll: Optimization of sample preparation for pesticide analysis in cannabis flower

255th National Meeting (2018)

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