Electrochemical L-Dopa Sensor based on Carbon Nanotube and Molecularly Imprinted Polymer Modified Carbon-Ceramic Electrode

Molecularly imprinted polymer were prepared using L-Dopa as template, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross linker and 2,2–azobis (2–methyl propionitrile) as initiator. The MIP was embedded in the multi walled carbon nanotube modified carbon ceramic electrode (MWCNT–CCE), which acted as the selective recognition element and pre–concentrator agent for L-dopa. The effect of different factors such as MIP and MWCNT amounts at preparation of electrode, also pH of pre-concentration solution and time of L-dopa accumulation on oxidation current of accumulated L-dopa at electrode surface were investigated and optimized with Central Composite Design. The optimum conditions for construction of MIP based sensor including 0.01 g MIP and 0.01 g MWCNT, also best condition for accumulation and pre-concentration of L-Dopa on sensor surface were found to be solution pH of 2.38 duration 14.5 min. The results showed that MIP/MWCNT/CCE has enough capability for accumulation and trapping of L-Dopa molecules available in solution.The linear response range and detection limit were found to be 24.0 to 720.0 nM and 7.5 nM, respectively using the differential pulse voltammetry method (DPV). The results showed that the proposed sensor is highly selective, sensitive with a fast response for L-Dopa analysis.

Keywords:

Molecularly Imprinted Polymer , Nano–sensor , L-dopa , Carbon ceramic electrode , Central Composite Design