The analytical determination and electrochemiluminescence behavior of amoxicillin
Li-Hua Shen a,b,*, Hong-Ni Wang b, Pei-Jing Chen b, Chun-Xia Yu b,
Yao-Dong Liang b, Cheng-Xiao Zhang a,**
a School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China
b School of Chemistry & Chemical Engineering, Xi'an University of Science & Technology, Xi'an 710054, PR China
A novel electrochemiluminescence (ECL) luminophor of amoxicillin was studied and found to generate ECL following the oxidation or reduction of amoxicillin. The amoxicillin oxidation state was also found to eliminate the reduction state, generating ECL. When solutions of amoxicillin were scanned between +1.5 V and −1.0 V with a graphite electrode in the presence of cetyltrimethyl ammonium bromide using KC1 as the supporting electrolyte, ECL emissions were observed at potentials of −0.7 V and +0.5 V. The ECL intensity at −0.7 V was enhanced by H2O2. Based on these findings, an ECL method for the determination of the amoxicillin concentration is proposed. The ECL intensities were linear with amoxicillin concentrations in the range of 1.8 × 10−8 g/mL to 2.5 × 10−7 g/mL, and the limit of detection (signal/noise = 3) was 5 × 10−9 g/mL. The florescence of amoxicillin had the greatest emission intensity in a neutral medium, with the emission wavelength dependent on the excitation wavelength. The experiments on the ECL mechanism for amoxicillin found that the electrochemical oxidation products of dissolved oxygen and active oxygen species contributed to the ECL process. The data also suggest that the hydroxyl group of amoxicillin contributed to its ECL emission.
Keywords: amoxicillin, electrochemiluminescence