a β-cd/mwcnt-modified-microelectrode array for rapid determination of imidacloprid in vegetables

This work introduces a β-cyclodextrin/multi-walled carbon nanotube (β-cd/mwcnt)–modified microelectrode array (mea) for rapid determination of imidacloprid in vegetables. the mea, fabricated on a silicon wafer, contains 20 parallel-connected working electrodes, a counter electrode and a reference electrode. the mwcnt is drop-casted onto the working electrode area, and β-cd is decorated onto the mwcnt layer with electropolymerization. electrochemical behaviors of the as-fabricated sensor are investigated with cyclic voltammetry (cv), electrochemical impedance spectroscopy (eis), and differential pulse voltammetry (dpv). obtained results validate that the proposed sensor has a large electroactive area, great electrical conductivity, and high sensitivity. during preparation and application of the sensor, 0.5 mg ml−1 mwcnt suspension and phosphate-buffered solution (0.1 mol l−1, ph = 7) are found to optimize experimental conditions. under optimized conditions, a wide linear range as 5 to 100 μmol l−1 is obtained for target imidacloprid, and the limit of detection (lod, s/n = 3) is well defined as 0.629 μmol l−1. the sensor is used for sensing imidacloprid in cabbage, cucumber, and tomato. the results from this method are in accordance with high-performance liquid chromatography-mass spectrometry (hplc-ms) data.