Aptamer-conjugated MoS2 for enrichment and direct detection of small molecules in laser desorption/ionization mass spectrometry

In this work, MoS2 nanosheets were synthesized by the chemical exfoliation method and then modified with a thiol-terminated aptamer via a simple thiol functionalization route. The as-made nanomaterial was characterized by UV-vis absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy. By integrating the advantages of MoS2 nanosheets and the recognition ability of aptamers, the functionalized nanomaterial has been successfully employed for simultaneous enrichment and analysis of sulfadimethoxine by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). The aptamer-conjugated MoS2 showed an excellent capture ability to eliminate background signals from the species co-existing in a milk sample. The simplicity of the synthesis method and the excellent performance of aptamer-conjugated MoS2 make it an ideal candidate for application in selective MS analysis of the target analyte from complex samples.