Surface effects of mesoporous silica modified electrode and application in electrochemical detection of dopamine.

Mesoporous silica nanoparticles (meso-SiO(2)) were synthesized and used to modify the surface of carbon paste electrode (CPE). The surface properties of CPE and meso-SiO(2)/CPE were examined. Compared with the unmodified CPE, meso-SiO(2)/CPE remarkably enhances the peak currents of K(3)[Fe(CN)(6)]. The effective surface areas of CPE and meso-SiO(2)/CPE were calculated to be 0.042 cm(2) and 0.208 cm(2), indicating that meso-SiO(2) possesses notable surface enhancement effect. Moreover, the electrochemical behaviors of dopamine (DA) were examined. At the meso-SiO(2)/CPE, the oxidation signals of DA greatly increase, and the oxidation potential shifts negatively, suggesting that meso-SiO(2)/CPE exhibits catalytic activity to DA. Based on this, a sensitive and simple electrochemical method was developed for the detection of DA. The linear range is from 0.4 microM to 25 microM, and the limit of detection is as low as 0.1 microM.