As a synthetic broad-spectrum antibiotic, chloramphenicol (CAP) is widely used in the prevention and treatment of bacterial diseases in aquaculture and animal husbandry, which might lead to severe water contamination and thus threaten our health. Herein, a novel electrochemical strategy for CAP detection is proposed with a sensor constructed based on the anodic peak (about -0.56 V) by modifying silver nanoparticles (AgNPs) and thiophene (TP) on a glassy carbon electrode (GCE) as a synergistic amplification unit with a simple step-by-step electrodeposition technique. Electrochemical methods, scanning electron microscopy, and X-ray energy dispersive spectroscopy were applied to characterize the as-prepared sensor. The TP/AgNPs/GCE sensor was used for CAP detection by DPV in the concentration range of 100.0 to 1600.0 µM, the limit of detection was 33.0 µM, and the sensitivity was 0.290 μA·µM-1·cm-2. In addition, the sensor has the advantages of simple preparation, low cost, good repeatability, stability, and anti-interference. It has been used for the detection of CAP in lake water with a recovery of 101.80 to- 104.85%, and the relative standard deviation was lower than 1.22%, which confirms that the sensor has good practicability.

Quercetin (Qu) is one of the most abundant flavonoids in the human diet. High concentrations of Qu can easily cause adverse effects and induce inflammation, joint pain and stiffness. In this study, Heme was used as a sensitive element and deposited and formed nanorods on a glassy carbon electrode (GCE) for the detection of Qu. The Heme/GCE sensor was characterized using scanning electron microscopy (SEM), cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques. Under optimized conditions, the developed sensor presented a linear concentration ranging from 0.1 to 700 μmol·L−1 according to the CV and DPV methods. The detection limit for the sensor was 0.134 μmol·L−1 and its sensitivity was 0.12 μA·μM−1·cm−2, which were obtained from CV analysis. Through DPV analysis we obtained a detection limit of 0.063 μmol·L−1 and a sensitivity of 0.09 μA·μM−1·cm−2. Finally, this sensor was used to detect the Qu concentration in loquat leaf powder extract, with recovery between 98.55–102.89% and total R.S.D. lower than 3.70%. The constructed electrochemical sensor showed good anti-interference, repeatability and stability, indicating that it is also usable for the rapid detection of Qu in actual samples.