Fmoc-Pro-Phe-OMe dipeptide carbon sensor for simultaneous detection of chloramphenicol (CP) and furazolidone (FZ) toxic residues in food samples.

In this work, we fabricated the Fmoc-Pro-Phe-OMe modified carbon paste electrode (FPPO/MCPE) and used it for electrochemical detection of CP and FZ in a 0.1 M phosphate buffer solution (pH = 7). We characterized the Fmoc-Pro-Phe-OMe and applied it for the electrochemical detection of CP and FZ. The Mass spectroscopy, ¹HNMR, and FTIR measurements confirm the Fmoc-Pro-Phe-OMe chemical structure. Studying electrochemical sensor characteristics, variation of scan rate parameters, and electrode surface area is crucial for understanding and optimizing the performance of modified and unmodified carbon paste electrodes. The FPPO/MCPE-modified carbon paste electrode has better sensing capabilities than the unmodified bare carbon paste electrode (BCPE). The FPPO/MCPE sensor has two linear ranges: 50-450 μM (CP) with a detection limit of 0.014 μM and 50-450 μM (FZ) with a detection limit of 0.015 μM. The FPPO/MCPE sensor is highly sensitive, measuring 4.25 µA/µM/cm² for CP and 4.1 µA/µM/cm² for FZ. Scan rate and concentration tests demonstrate that the oxidation of CP and FZ is a diffusion-controlled electrode process. The FPPO/MCPE sensor also demonstrates excellent repeatability, reproducibility, stability, and selectivity for detection of CP and FZ. The use of FPPO/MCPE-sensor is demonstrated for the detection of FZ and CP in milk and honey samples.