Quantitative Analysis of Cannabis Extracts at Different Alcohol Concentration and Extraction Time using HPLC Analysis

Abstract

This study examined the effects of varying alcohol concentrations—60%, 70%, 80%, 90%, and 95%—as well as extraction times—3, 7, and 30 days. High-performance liquid chromatography was used in a quantitative analysis in order to determine THC concentrations in the extracts. In Thailand, the law stipulates that THC concentrations in cannabis extracts used in the food, cosmetics, and herbal medicine industries, as well as in industries, must not exceed 0.2%. The analysis results showed that THC concentrations obtained via extraction for three and seven days with the majority of alcohol concentrations used in this study did not excess 0.2%. THC content of 0.2419 %w/w and CBD concentration of 0.0037 percent w/w were obtained via extraction using 95% alcohol, exceeding the 0.2% threshold. The THC and CBD concentrations from 30-day extraction were 0.2606, 0.2500, 0.2020, 0.2152, and 0.2137 %w/w and 0.0042, 0.0041, 0.0034, 0.0032, and 0.0030 %w/w, respectively. Therefore, the extracts need to be diluted with alcohol before use in order to keep the THC content under 0.2%. However, additional quantitative HPLC analysis is required. The contents of cannabis active substances were shown to be influenced by the extraction time and alcohol concentration. However, after a period of time, the contents of these substances remained constant. Therefore, the extraction period should not be longer than seven days, and the alcohol concentration should be between 60 and 90%.