High throughput method for determination of caffeine in coffee drinks

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Lýdia Mihalčíková Supervisor: Warunya Boonjob, Ph.D. Consultant: Doc. PharmDr. Hana Sklenářová, Ph.D. Work title: High throughput method for determination of caffeine in coffee drinks Caffeine is a xanthine alkaloid acting like a stimulant of heart and central nervous system. Quantification of caffeine in coffee drinks is significant to show how much of caffeine was in each cup which has been taken per day prior to prevent a caffeine overdose. The development of high-throughput sequential injection analysis (SIA) spectrophotometric assay for the determination of caffeine in coffee drinks was performed. Sample was treated with carrez reagent for matrix suppression followed by filtration thereafter analyte was isolated from organic acids by a short C18 monolithic column (10x4.6mm). The flow rate of the separation step was 10 µL s-1 with 10 % v/v of methanol as the mobile phase. Caffeine was detected at 274 nm. The influence of main parameters affecting the quantification of caffeine was optimized. Duration of one sample analysis was 15 minutes. During one hour it was possible to analyze 4 samples. Linear range was 1 - 15 mg L-1 and determination coefficient (r2 ) was 0.9969. The limit of..