Magnetic nitrogen-doped porous carbon sorbents derived from NH2-MIL-88(Fe) for efficient extraction of chloramphenicol in honey samples

One-step synthesis of magnetic nitrogen-doped porous carbon (MNPC). • The addition of urea promotes the graphitization degree of MNPC. • MNPC serves as an MSPE adsorbent with excellent reusability. • Good analytical performance for chloramphenicol in honey is obtained. Magnetic porous carbon (MPC) materials derived from metal-organic frameworks (MOFs) inherit the high porosity and tunable pore structure of MOFs and also endow the materials with magnetic response, demonstrating great potential for magnetic solid-phase extraction (MSPE). However, MPCs obtained directly by carbonizing MOFs suffer from issues such as easy pore collapse and a single surface chemical functionality, which necessitate modification methods to improve their performance. The nitrogen-doping strategy offers unique advantages in charge distribution, the creation of active sites, alterations in surface chemical properties, and enhanced structural stability. Therefore, a magnetic nitrogen-doped porous carbon (MNPC) derived from NH 2 -MIL-88(Fe) was developed as an MSPE adsorbent, combined with liquid chromatography, for sensitive determination of trace amounts of chloramphenicol in honey samples. The developed method exhibits a good linear relationship in the range of 0.05-50 μg·L -1 , with R 2 of 0.9999, LOD (S/N=3) of 0.005 μg·L -1 , and LOQ (S/N=10) of 0.02μg·L -1 . The spiked recovery rate ranged from 93.5% to 99.2%, and the RSD ranged from 1.3% to 10.7%. Therefore, this method has significant potential for routine monitoring of chloramphenicol residues in food safety supervision.