Optimization of Caffeine Extraction from Various Tea Types Using Dichloromethane as an Organic Solvent ^†

Caffeine, as 1,3,7-trimethyl-1H-purine-2,6-dione, represents a naturally occurring alkaloid within the methyl xanthine family. Exhibiting bitterness and an odorless state in its pure form, caffeine manifests as needle-like crystals. Found abundantly in tea, coffee beans, kola nuts, and cocoa beans, this compound possesses stimulating effects on the central nervous system, respiration, and cardiac activity. Ubiquitously present in everyday products such as soft drinks, tea, coffee, chocolates, pharmaceutical drugs, and skincare items, caffeine plays a pivotal role. This study focuses on the extraction of caffeine from various tea types, including used tea, utilizing dichloromethane as an organic solvent. Investigating the impact of temperature and residence time on extraction efficiency, we observed a direct correlation between these factors and efficiency. Notably, the residence time exhibited a significant effect up to a certain threshold, beyond which no substantial difference in extraction efficiency was observed. The optimal conditions for caffeine extraction were identified at 100 °C with a residence time of 30 min. The findings revealed the extraction of 0.089 g of caffeine from black tea, 0.06 g from used black tea, 0.08 g from green tea, and 0.047 g from used green tea.