Electrochemical sensor for the simultaneous determination of caffeine and aspirin in human urine samples

A simple and sensitive electrochemical method has been developed for the determination of acetyl salicylic acid (ASA) and caffeine (CAF) using edge plane pyrolytic graphite electrode (EPPGE). At pH 7.2, two well defined peaks with peak potential (Ep) of ∼1225 mV and ∼1335 mV were appeared for the oxidation of ASA and CAF, respectively. Anodic peaks for ASA and CAF showed a systematic increase in peak current with increase in concentration in the range 0.02–100 μM with sensitivity of 0.16 and 0.17 μA/μM, respectively. Detection limits (3σ/slope) for ASA and CAF were found to be 0.01 and 0.008 μM, respectively whereas, the limit of quantifications were found to be 0.032 and 0.026 μM, respectively. The proposed sensor has been utilized for the simultaneous determination of ASP and CAF in human urine samples, pharmaceutical preparations and coffee beverages.