Voltammetric Study And Determination Of Phenothiazine Derivates Using Thiols And Carbon Nanotubes Modified Gold Electrodes

Phenothiazine and its derivatives are a kind of antidepressive drugs and widely used in the treatment of psychotic diseases. There have been many reports about their characteristics and functions. Electrochemical methods are very important due to the simple procedures and high sensitivity. In this paper, the thiol self-assembled monolayers (SAM) and carbon nanotubes (CNTs) modified gold electrodes were used to study the electrochemical behaviors of trifluoperazine, fluphenazine, prochlorperazine and their voltammetric determinations were proposed. The thesis includes the following researches:(1) The electrochemical behavior of trifluoperazine at decanethiol self-assembled monolayer modified gold electrodes (i.e. C10H21SH/Au SAM) was studied. Trifluoperazine could effectively accumulate at this electrode and generate a sensitive anodic peak at about 0.63 V (vs. SCE). The anodic peak current was linear to trifluoperazine concentrations over a certain range. This method was successfully applied to the determination of trifluoperazine in drug samples. In addition, it was found that SDS could make the anodic peak current increase while cation surfactants, nonionic surfactants and organic solvents make it reduce greatly. In the presence of SDS, the peak at about 0.63 V turned into two peaks, suggesting the electron transfer changed from one-step to two-step. Because trifluoperazine could not easily get out of the monolayer, the regeneration of this electrode was rather difficult.(2) The carboxylic multi-walled carbon nanotubes were immobilized on the (3-mercaptopropyl)trimethoxysilane self-assembled monolayer modified gold electrodes. Thus a novel MWNTs/MPS/Au bilayer modified electrode was fabricated. By means of this electrode, the electrochemical behavior of fluphenazine was studied and it was found that fluphenazine could effectively accumulate at this bilayer modified electrode and generate two anodic peaks at about 0.78 V and 0.93 V (vs. SCE) respectively. The peak at 0.78 V was more sensitive and fit for the analysis. This method was applied to the determination and the result was satisfying. This electrode had good selectivity and could be easily regenerated.(3) Minor amount of carboxylic multi-walled carbon nanotubes was dropped on the surface of the dodecanethiol self-assembled monolayer modified gold electrodes. Thus the MWNTs/DDT/Au bilayer modified electrode was fabricated. The electrochemical behaviorsof prochlorperazine at the two different modified electrodes were comparatively investigated. It was found that the bilayer modified electrode had good stability and reproducibility. Compared with (2), the preparation of the bilayer modified electrodes was much simpler. In comparison with the traditional GNTs modified glassy carbon electrodes, the response of the bilayer modified electrode was more sensitive. Meanwhilei the different accumulation mechanisms of prochlorperazine at DDT/Au and MWNTs/DDT/Au were proposed.