Solid Phase Extraction - Voltammetric Coupled Detection of Caffeine in Acetonitrile

Caffeine (CAF) in aqueous solutions was extracted into acetonitrile (MeCN) using solid phase extraction (SPE). The voltammetric detection of CAF in MeCN was performed in a microcentrifuge tube after SPE in order to minimise the required amount of MeCN and reagents used during the analysis. The voltammetric determination of CAF from a range of beverages extracted into MeCN was in good agreement with the results obtained from HPLC measurements on the same samples. The SPE‐coupled voltammetric method gave more accurate results than those obtained via the direct voltammetric detection of CAF in real beverage samples.