Magnetic Boric Acid-activated Biochar Adsorbents for Efficient Extraction of Chloramphenicol in Honey Samples

Single biochar materials have limitations, including limited adsorption capacity, poor selectivity, and poor recyclability. Some activation methods are needed to modify them to improve their performance. Boric acid modification offers unique advantages, including increased specific surface area, optimized pore structure, introduction of oxygen-containing functional groups, and improved yield. Herein, a magnetic boric acid-activated biochar was developed as an adsorbent for magnetic solid-phase extraction in combination with liquid chromatography for the efficient extraction and sensitive determination of trace amounts of chloramphenicol in honey samples. The developed method showed good linearity in the range of 0.1-500 µg·L^-1 with R² of 0.9999, limit of detection (signal-to-noise ratio [S/N] = 3) of 0.01 µg·L^-1, and limit of quantification (S/N = 10) of 0.03 µg·L^-1. The spiked recovery rate ranged from 82.0% to 107.8%, and the relative standard deviation ranged from 0.5% to 10.0%.