Enzyme-Assisted\nSolid-Phase Microextraction Coupled\nwith a DNA Nanowalker for Dual-Amplified Detection of Chloramphenicol\nin Animal-Derived Food Products

Chloramphenicol (CAP), an aminoalcohol antibiotic, exerts\nits action\non bacterial ribosomes, thereby obstructing protein synthesis. However,\nthe use of CAP in husbandry may lead to its excessive accumulation\nin animal-derived food products. This presents potential risks to\nconsumer health. This study developed a novel dual-amplification fluorescence\ndetection method by integrating enzyme-assisted solid-phase microextraction\n(SPME) with a Fe<sub>3</sub>O<sub>4</sub>@Au NP-based DNA nanowalker\nfor the detection of CAP in food. The combination of a quartz rod-based\nSPME biosensor and DNA nanowalker effectively eliminated matrix interference,\nenabling the conversion of CAP and enhancement of detection signals\nthrough two cyclic amplification processes. The strategy demonstrated\nhigh sensitivity with a limit of detection of 28.1 aM as well as a\nwide linear range from 0.1 fM to 1 nM (with <i>R</i><sup>2</sup> > 0.99). This method also demonstrates robust stability\nand\naccuracy in detecting trace amounts of CAP in both authentic and prepared\npositive samples.