This work describes the first report about the simultaneous determination of levodopa (L-DOPA) with folic acid (FA) and uric acid (UA) based on electrocatalytic oxidation of LDOPA with peroxidase properties of hemoglobin (Hb) in the presence of H2O2 as Hb activator. Bovine Hb was electrostatically immobilized on WO3 nanoparticles (WO3NPs) in pH between Hb and WO3NP isoelectric points, and subsequently, a carbon paste electrode (CPE) was modified with the obtained WO3NPs-Hb and multiwalled carbon nanotubes (MWCNTs). The resulting biosensor supplied a sensitive and suitably stable biosensor for the simultaneous determination of L-DOPA, UA, and FA. The obtained linear range and detection limit for LDOPA, UA, and FAwere completely acceptable, and the biosensor response time for these molecules was relatively short so that it reaches about 95 % of its maximum response in less than 10 s. The applicability of the current biosensor was confirmedwith the determination of L-DOPAin the presence of fixed amounts of FA and UA in some real samples by the standard addition method.
