La-doped ZnO nanorods were successfully synthesized by a solvothermal synthesis route using ethanol as the solvent. The morphologies and composition were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). A new electrochemical sensor was fabricated based on the as-synthesized nanorods and the electrochemical behaviors of bisphenol A (BPA) on modified carbon paste electrode (CPE) were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The experimental results confirmed that La-doped ZnO nanorods exhibit excellent electrocatalytic activity toward the oxidation of BPA. By using CV method, a lower detection limit of 0.1 μM (S/N = 3) with the linear calibration curves over the concentration range 0.4∼90 μM were obtained. Besides, the interference experiments and the actual analysis of BPA were performed. The sensor has potential application in the fields of biomedical and environmental science.Bisphenol A (BPA) [4, 4 -(1-Methylethyliden) bisphenol] is an important phenolic compound with a structure analogous to endocrine hormones, such as estradiol and diethylstilbestrol. That is why BPA shows estrogenic potential, 1 acute toxicity toward aquatic organisms 2 and human cultured cells. 3 In addition, BPA was acknowledged to cause reproductive disorders including decrease of sperm quality in humans, reduction of immune function, impairment of reproduction and so on. 4 Therefore, it is very important to establish a sensitive and simple method for the determination of BPA. Up to now, plenty of strategies such as fluorescence, 5 high performance liquid chromatography, 6 gas chromatography-mass spectrophotometry, 7 electrochemistry 8 and other analytical techniques have been reported to sensitively detect BPA. Among these methods, electrochemically analytical technique, especially chemically modified electrode (CME), is frequently used because of its excellent catalytic activity, physical stability and so on. [9][10][11] Currently, various materials, including molecularly-imprinted polymer, metal composites and nanoparticles, have been used for the construction of CMEs to determine BPA. For example, Ai et al. fabricated a electrochemical sensor for sensitive detection of BPA using cobalt phthalocyanine modified carbon paste electrode and the limit of detection (LOD) was 10 nM. 12 TiO 2 nanotubes and MIPs (polypyrrole), 13 Mg-Al layered double hydroxide, 14 and chitosanFe 3 O 4 15 were also used for the sensitive BPA detection. LODs were estimated to be 2.0 nM, 5.0 nM, and 8.0 nM, respectively. Moreover, tyrosinase based chemical sensor was developed for monitoring BPA with LOD of 20 nM. 16 These results showed that different kinds of modified materials have significant influence on the sensitivity and selectivity of CMEs. According to previous researches, 17,18 the nanoscale metal-oxide plays a vital role in the modification of CME owing to its high specific surface area, good compatibility and stability. Many ele...
