Metal-organic frameworks in matrix solid-phase dispersion for the extraction of phytochemicals from Cannabis sativa L. samples

Fiber-type Cannabis sativa L. is a plant species known for its easy cultivation and rich phytocomplex, which mainly includes terpenoids, non-psychotomimetic cannabinoids, and flavonoids. These compounds are well-known for their health benefits for human health, including antioxidant, anti-inflammatory, and calming effect. For these reasons, this crop is now the subject of renewed interest in many fields such as pharmaceutical and nutraceuticals, among others. Due to the high complexity of this plant, sample preparation is normally necessary to make the sample compatible with downstream analysis. Different approaches have been developed to extract and isolate bioactive compounds from Cannabis sativa L. matrices. These methods normally are tedious, involve time-consuming sample preparation steps, and require the consumption of large amount of organic solvent to extract the analytes of interest. To limit the use of toxic solvents and streamline the overall process, it is crucial to develop more sustainable and efficient methods for the extraction of natural compounds. Metal-organic frameworks (MOFs) are a class of crystalline materials composed of metal ions connected by organic ligands through coordination bonds. These materials are characterized by the presence of accessible cages, tunnels and modifiable pores, and exhibit the highest known surface areas. Due to their impressive features, together with their versatility, MOFs have gained significant attention in different scientific field, including sample preparation. In this field, MOFs are employed sorbents in different procedures, including solid-phase extraction and different modes of solid-phase microextraction. In this study, we propose the use of MOFs as sorbents in matrix solid-phase dispersion (MSPD) to extract non-volatile phytochemicals from different Cannabis sativa L. samples. This technique consists in the direct mechanical blending of the sample (usually a solid) with a solid sorbent, which allows to clean-up and homogenize the matrix. Different MOFs have been tested as sorbents, being the MOFs CIM-80(Al) selected for its higher capacity to efficiently extract both flavonoids and cannabinoids from Cannabis sativa L. samples. Several experimental conditions (amount of sorbent and desorption step) were optimized using an experimental design to obtain the maximum extraction efficiency. In comparison to traditional extraction approaches, the resulting methodology is easier, quicker, and more environmentally friendly while keeping the requirements in terms of sensitivity for the target analytes.