Magnetic molecularly imprinted polymer based on coordination for the determination of trace banned substance furosemide in human urine

Furosemide (FUR), banned in sports events by the World Anti-Doping Agency, is a key target in drug tests, necessitating a pretreatment material capable of selectively, rapidly, and sufficiently separating/enriching analytes from complex matrices. Herein, a metal-mediated magnetic molecularly imprinted polymer (mMIP) was rationally designed and synthesized for the specific capture of FUR. The preparations involved the utilization of chromium (III) as the binding pivot, (3-aminopropyl)triethoxysilane as functional monomer, and Fe₃O₄ as core, all assembled via free radical polymerization. Both the morphologies and adsorptive properties of the mMIP were characterized using multiple methods. The resulting Cr(III)-mediated mMIP (ChM-mMIP) presented excellent selectivity and specificity toward FUR. Under optimized conditions, the adsorption capacity reached 128.50 mg/g within 10 min, and the imprinting factor was 10.41. Moreover, it was also successfully applied as a dispersive solid-phase extraction material, enabling the detection of FUR concentration as low as 20 ng/mL in human urine samples when coupled with a high-performance liquid chromatography/photodiode array. Overall, this study offers a valuable strategy for the development of novel recognition material.