A new strategy for determination of bisphenol A in the presence of Sudan I using a ZnO/CNTs/ionic liquid paste electrode in food samples

The electrochemistry of bisphenol A (BPA) was studied by voltammetric methods at a surface of carbon paste electrode modified by a ZnO/CNTs nanocomposite and room-temperature ionic liquid of 1,3-dipropylimidazolium bromide. The ratio of ZnO/CNTs and ionic liquid (IL) on the surface of the electrode has to be controlled carefully because the charging currents. The anodic peaks of BPA and Sudan I in their mixture can be well separated. At pH 7.0 the two peaks are separated ca. 0.47 and 0.70 V, respectively; hence BPA can be determined in the presence of Sudan I and more than 8.7 times current excess of BPA. The peaks current of square wave voltammograms (SWV) of BPA and Sudan I increased linearly with their concentration in the ranges of 0.002-700 μmol L−1 BPA and 0.2-800 μmol L−1 Sudan I. The detection limits for BPA and Sudan I were 9.0 nmol L−1 and 80 nmol L−1, respectively. The modified electrode has been successfully applied for the assay of BPA in food samples. This study provides a simple and easy approach to selectively detect BPA in the presence of Sudan I.