Electrochemical determination of paraquat using a DNA-modified carbon ionic liquid electrode

Deoxyribonucleic acid (DNA) was electrochemically deposited on a carbon ionic liquid electrode to give a biosensor with excellent redox activity towards paraquat as shown by cyclic voltammetry and differential pulse voltammetry. Experimental conditions were optimized with respect to sensing paraquat by varying the electrochemical parameters, solution pH, and accumulation time of DNA. Under the optimized conditions, a linear relation exists between the reduction peak current and the concentration of paraquat in the range from 5 x 10(-8) mol L(-1) to 7 x 10(-5) mol L(-1), with a detection limit of 3.6 x 10(-9) mol L(-1). The utility of the method is illustrated by successful analysis of paraquat in spiked real water samples.