Electrochemical fingerprinting of cephalosporin antibiotics and its applications for investigations of hydrolysis behavior

Abstract

Cephalosporin, as one of the most widely used antibiotics, study of its hydrolysis process is important for predicting their environmental persistence. Two critical factors are considered has the first priority, which are hydrolysis rate constant (kh) and half-life (t1/2). To date, many efforts have been made by using various analytical techniques to obtain the data for calculating kh and t1/2. However, the typical techniques such as UV/vis spectrophotometry and liquid chromatography are of significant challenges like low accuracy and timely operations. Herein, we explored an electrochemical method by identifying the characteristic peaks with the same parent nuclear structure through square wave voltammetry (SWV). This proposed electrochemical fingerprinting was able to track the hydrolysis of intact cephalosporin molecules, β-lactam ring, and transformation product. The kh and t1/2 of cefadroxil (CDX) under pH = 7 and 25 °C by electrochemical (0.0640 d−1 and 11.0 d) were consistent with those of high-performance liquid chromatography-UV/vis (HPLC-UV/vis) (0.0660 d−1 and 10.7 d). The t1/2 ranged from 3.40 to 36.2 d, 7.33 d–43.7 d and 9.63 d–45.3 d for base-catalyzed, neutral pH and acid-catalyzed hydrolysis hydrolyzed, respectively, indicating that base-catalyzed hydrolysis rates were the greatest under alkaline conditions. Meanwhile, hydrolysis rates increased 2.50–3.60-fold for every 10 °C raise in temperature. Besides, the electrochemical fingerprinting could realize cephalosporin and β-lactam ring hydrolysis rates close to 100% in-situ hydrolysis process monitoring. This present work provides a powerful technology for understanding the environmental fate and predicting the environmental behavior of antibiotics with fast, high accuracy, specific recognition, and in situ monitoring.