Simple and rapid detection of l-dopa based on in situ formation of polylevodopa nanoparticles

Levodopa [L-3, 4-dihydroxyphenylalanine, or l-DOPA] is an important neurotransmitter used for the treatment of neural disorders such as Parkinson’s disease. Abnormal l-Dopa concentrations in biological fluids can be used for the evaluation of such diseases. In this work, a rapid and sensitive method for l-DOPA detection has been reported which is based on in situ formation of polylevodopa nanoparticles. Under alkaline conditions, l-DOPA is spontaneously oxidized to its quinone derivative and shows fluorescence properties. The fluorescence signal of the oxidation product has been monitored and used for the determination of l-DOPA in the presence of dopamine, uric acid, ascorbic acid and other interferents. The developed assay shows excellent selectivity towards l-DOPA. The limit of detection (LOD) of this method is evaluated to be 29.0 nM with a linear range of 0.3–100.0 μM.