Molecularly imprinted polymer-decorated magnetite nanoparticles for selective sulfonamide detection

Sulfonamides are known not only to be antimicrobial drugs that lead to antimicrobial resistance but also to be chemotherapeutic agents that may be allergenic and potentially carcinogenic, which represents a potentially hazardous compound once present in soil or water. Herein, a hybrid material based on molecularly imprinted polymer (MIP)-decorated magnetite nanoparticles for specific and label-free sulfonamide detection is reported. The composite has been characterized using different spectroscopic and imaging techniques. The magnetic properties of the composite are used to separate, preconcentrate, and manipulate the analyte which is selectively captured by the MIP onto the surface of the composite. Screen printed electrodes have been employed to monitor the impedance levels of the whole material, which is related to the amount of the captured analyte, via electrochemical impedance spectroscopy. This composite-based sensing system exhibits an extraordinary limit of detection of 1 × 10 mol L (2.8 × 10 ppb) (S/N = 3), which is close to those obtained with liquid chromatography and mass spectrometry, and it was demonstrated to screen sulfamethoxazole in a complex matrix such as seawater, where according to the literature sulfonamides content is minimum compared with other environmental samples.
This work was supported by The European Commission Program, FP7-OCEAN, SMS Project (613844). ICN2 acknowledges support from the Severo Ochoa Program (MINECO, Grant SEV-2013-0295). Nanobiosensors and Bioelectronics Group acknowledges Supramolecular NanoChemistry and Materials group (Dr. Carlos Carbonell and Prof. Daniel Maspoch at ICN2) for BET measurements, and the support from Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya (2014 SGR 260). L.A.M acknowledges financial support from FAPESP-BEPE (2014/26088-4) project.