Preparation and Application of Electrochemiluminescence Sensor by Immobilizing Tris(2, 2′-bipyridine) ruthenium(II) on the Surface of Gold Electrode with Silica sol/Nano-Au/PVP/L-cysteine

In order to establish a simple, sensitive and rapid method for the determination of azithromycin, the gold electrode modified with Silica sol/Nano-Au/PVP/Ru(bpy)32+ was prepared, and the electrochemiluminescence (ECL) method was developed for the determination of azithromycin based on the sensitizing effect of azithromycin on Ru(bpy)32+. Moreover, the electrochemical behaviors and the electrochemical luminescence behaviors of the Ru(bpy)32+ system and the Ru(bpy)32+- azithromycin system were investigated by ECL respectively. The results show that the proposed electrode showed very good electrochemical activity and electrochemiluminescence response to the Ru(bpy)32+- azithromycin system, under the optimum experimental condition, the linearity of azithromycin concentration to ECL intensity was achieved in the concentration of azithromycin from 1.0 × 10−7 to 1.0 × 10−4 mol L−1 and the detection limit (S/N = 3) was 1.33 × 10−9 mol L−1. Through the parallel determination of 1.0 × 10−5 mol L−1 azithromycin for 8 times, the RSD of results was 1.82%, and the recovery ranging from 97.9% to 101.6% was obtained in the detection of azithromycin tabelets and the RSD was 1.36% (n = 5). The proposed method showed high selectivity and sensitivity and simplicity, and it could be applied to the analysis of azithromycin with satisfactory results.