CoFeMn-layered double hydroxide-decorated MXene for high-performance electrochemical sensing of ciprofloxacin in food and water samples

A metal-organic framework (MOF)-derived layered double hydroxide (LDH)/MXene nanocomposite for the electrochemical detection of ciprofloxacin (CIPF) in food and water samples is presented for the first time. CoFeMn-LDH (positively charged) was synthesized using ZIF-67 as a sacrificial MOF template and then combined with Ti₃C₂T_x MXene layers (negatively charged) to form a new hierarchical nanocomposite. The resultant nanocomposite was drop-cast onto a screen-printed carbon electrode (SPCE), which is cost-effective and easily incorporated into handheld devices for on-site testing. The synergistic interactions between electrically conductive MXene and catalytically active CoFeMn-LDH considerably enhanced the electrochemical CIPF sensing performance: a wide linear range from 0.079 to 521 µM with a low detection limit of 0.013 µM and high sensitivities of 3.41 and 1.51 µA/µM/cm². The developed sensor also showed excellent selectivity, reproducibility, reusability, and long-term stability. Moreover, it detected CIPF in real milk, honey, and water samples with good recoveries and relative standard deviations (< 5%), which were similar to those with UV-Vis spectrophotometry.