Voltammetric sensing of promethazine on a multi-walled carbon nanotubes coated gold electrode

The voltammetric study of promethazine on multi-walled carbon nanotubes ( MWNTs) coated gold electrode ( MWNTs/Au) has been carried out. Promethazine can cause a sensitive anodic peak on it. In pH=4.0 phosphate buffer solution, the peak potential is 0.66 V ( vs. SCE). The electrode process is adsorption-controlled, the adsorption amount is about 9.9 x 10(-10) mol cm(-2) ( for 1.0 x 10(-6) M promethazine), and the electron-transfer coefficient (alpha) is about 0.79. The influence of various experimental parameters on the voltammetric behavior of promethazine has been examined. Under the optimized conditions, the anodic peak current is linear to promethazine concentration in the range from 5.0 x 10(-8) to 1.0 x 10(-5) M. After 120 s accumulation, the detection limit is 1.0 x 10(-8) M (S/N= 3). This method has been successfully applied to the determination of promethazine in medicine sample ( i. e. Compound Reserpine) and the recovery is 97.6- 101.8%. The electrode can be regenerated by successively repeating potential scan in a blank solution, and exhibits good reproducibility.