Hot electron-induced cathodic electrochemiluminescence at oil film-covered carbon paste electrode and application to nano-molar determination of catechol.

Hot electron-induced cathodic electrochemiluminescence of the Ru(bpy)(3)(2+)/S(2)O(8)(2-) system was investigated at an oil film-covered carbon paste electrode (CPE) under cathodic pulse polarization for the first time. Compared with other electrodes, the CPE is of lower background, better stability and reproducibility. The method is also applied to the determination of catechol. Under the optimum conditions, the linear correlation between the quenched ECL intensity (ΔI) and the logarithm of catechol concentration (logC(catechol)) was observed over the range of 2.0×10(-10) mol/L-4.0×10(-9) mol/L and 4.0×10(-9) mol/L-4.0×10(-7) mol/L with the limit of detection (LOD) of 2.0×10(-10) mol/L, which is lower than the other reported methods. The proposed method is applied to determine catechol in reservoir water. The mean recoveries of 83.3%-99.0% and the relative standard deviations (RSDs) of 0.8%-2.2% were obtained.