A disposable electrochemical sensor for the rapid determination of levodopa

Levodopa ( l-dopa), the biological precursor of catecholamines, is the most widely prescribed drug in the treatment of Parkinson's disease. The present work presents a proposal for the application of a gold screen-printed electrode an electrochemical sensor for monitoring l-dopa in stationary solution and a flow system. Using the electrooxidation of l-dopa at +0.63 V in acetate buffer pH 3.0 on a gold screen-printed electrode it is possible to obtain a linear calibration curve from 9.9 × 10 −5 to 1.2 × 10 −3 mol L −1 and a detection limit of 6.8 × 10 −5 mol L −1. Under amperometric conditions ( E app = 0.8 V; flow rate = 14.1 mL min −1; pH 3.0), an analytical calibration graph for l-dopa was obtained from 1.0 × 10 −6 mol L −1 6.6 × 10 −4 mol L −1 with a detection limit of 9.9 × 10 −7 mol L −1. The method was successfully applied to the determination of l-dopa in commercial dosage forms without any pre-treatment.