Electrochemical detection of chloramphenicol in marine sediment based on an oxygen vacancy defect-rich Co3O4/NC nanocomposite

Uniform Co 3 O 4 nanoparticles with abundant active sites loaded on the N-doped graphite carbon was prepared. • Co 3 O 4 /NC based electrochemical sensor was fabricated to detect chloramphenicol in environmental samples. • The proposed sensor presents wider linear ranges and lower detection limit. Chloramphenicol (CAP), a typical broad-spectrum antibiotic, poses considerable threats to human health due to its residues transferring through the food chain. Thus, the development of fast and highly sensitive detection technologies for CAP is of great practical importance. Herein, a Co 3 O 4 @NC nanocomposite was prepared via a controllable thermal decomposition-oxidation approach. This composite was further employed as an electrode modification material to construct a novel electrochemical platform, which was designed for the quantitative detection of CAP. Characterizations revealed that Co 3 O 4 nanoparticles were wrapped in the carbon sheet in the prepared Co 3 O 4 @NC nanocomposite with a specific surface area of 285.5 m 2 /g, along with affluent oxygen vacancy active sites. Electrochemical performance measurements indicated that Co₃O₄@NC exhibits excellent electrocatalytic reduction activity toward CAP. Under optimized experimental conditions, differential pulse voltammetry (DPV) was employed to detect CAP, and the sensor emerged a linear detection range of 0.1–500 μmol/L with a low detection limit of 12.4 nmol/L, outperforming most electrochemical sensors for CAP reported in previous papers. Additionally, it owned good selectivity, as the relative standard deviation (RSD) of the CAP detection signal was less than 5% even as the other familiar interfering species were concomitant. It also demonstrated remarkable stability, repeatability, and anti-interference ability. When applied to the actual determination of CAP residues in environmental samples, the sensor yielded recovery rates of 97.02%–104.23% for marine sediment samples and 99.77%–104.06% for seawater samples, with all RSD values below 5.1%. This study realizes the structural and performance regulation of Co₃O₄ materials through a simple and feasible strategy, providing a new sensing platform for the rapid detection of trace CAP and offering novel insights into the application of metal oxides in electrochemical sensing fields. Download: Download high-res image (126KB) Download: Download full-size image