Analysis of Contaminants in Hemp Using LC and GC Coupled to MS/MS
Hemp is a class of Cannabis sativa that contains significantly lower levels of tetrahydrocannabinol (THC) (below 0.3%, on a dry weight basis), and may have higher levels of cannabidiol (CBD). This agricultural commodity is being utilized as a source of fiber, protein, and cannabinoids. The 2018 Farm Bill authorized the production and distribution of hemp under federal law, and this led to a significant increase in the development and commercialization of hemp products. Like cannabis and other crops, dried hemp plant material may contain various contaminants that are harmful to humans. For this reason, robust analytical workflows capable of detecting low concentrations of pesticides and other contaminants in hemp and cannabis plant material are highly desired. This work describes a complete workflow for the analysis of diverse contaminants in hemp. Instrumental analysis was conducted using liquid chromatography (LC), and gas chromatography (GC) both coupled to tandem MS (MS/MS). Sample clean-up strategies involving extract dilution with water, and the use of solid phase extraction (SPE) cartridges were evaluated. Allowing enough time to resolve analytes from interferences remaining in the injected samples was crucial to enable the detection of all the target compounds. Analyte recoveries ranged from 68 to 120% in hemp samples spiked at 100 ppb. Satisfactory results in terms of LOQ, linearity, accuracy, and precision were obtained for all the tested contaminants. Overall, the presented workflow provides a reliable and easy approach to quantify multiple contaminants in hemp samples.