Simultaneous determination of levoDopa, uric acid and folic acid based on elextrocatalytical oxidation of levoDopa by Hb immobilized on WO3 nanoparticle

Levodopa (L-Dopa), a catecholamine drug, is mostly used in treatment of Parkinson’sdisease. People, who have Parkinson’s disease, are suffering from deficiency of Dopamine inthe brain. L-Dopa is used to increase Dopamine in the brain, which reduces the symptoms ofParkinson’s disease and provides symptomatic relief at the initial stages of the disease.Considering the serious side effects due to chronic administration of this drug in theParkinson's patients and also achieving the better its curative effects, determination of LDOPAhas been attracted many attentions in recent years [1, 2]. This work describes the firstreport about simultaneous determination of levoDopa (L-Dopa) with folic acid (FA) and uricacid (UA) as prevalent biologic interferences based on electrocatalytic oxidation of L-Dopawith peroxidase properties of hemoglobin (Hb) in presence of H2O2 as Hb activator. BovineHb was electrostatically immobilized on WO3 nanoparticles (WO3NPs) and subsequently acarbon paste electrode (CPE) was modified with obtained WO3NPs-Hb and multi-walledcarbon nanotube (MWCNTs). Resulted biosensor supplied a sensitive and suitably stablebiosensor for simultaneous determination of L-Dopa, UA and FA. Obtained linear range anddetection limit for L-Dopa, UA and FA were completely acceptable and biosensor responsetime for these molecules was relatively short so that reaches about 95% of maximumresponse in in less than 10 seconds. Applicability of current biosensor was confirmed withdetermination of L-Dopa in presence of fixed amounts of FA and UA in some real samplesby standard addition method.