Electrocatalytic reduction of chloramphenicol at multiwall carbon nanotube-modified electrodes.

A multiwall carbon nanotube-modified glassy carbon (GC) electrode was employed for the investigation of chloramphenicol (CAP) reduction. Carbon nanotube coating can greatly lower the overpotential of the electrochemical reduction of CAP and promote the electrode reaction. CAP undergoes an irreversible reduction process in phosphate buffer by the modified electrode. The reduction peak current (Ip) was significantly increased. Effects of some important factors, including pH, scan rate, and amount of modifier, on the determination of CAP were investigated. In the range of 3 x 10(-7) to 1.2 x 10(-5) M, the reduction peak current (Ip) has a good linear relationship with the concentration of CAP. When the signal-to-noise ratio is 3, the detection limit is 4.5 x 10(-8) M. The relative standard deviation of 10 measurements for 3 x 10(-6) M CAP is 5.3%, suggesting an excellent reproducibility of the modified electrode. Interfering experiments show that the modified electrode has excellent selectivity for the detection of CAP. The modified electrode was used to determine CAP in eyedrops, and the recoveries were approximately 100%.