Aptamer-conjugated MoS 2 for enrichment and direct detection of small molecules in laser desorption/ionization mass spectrometry.

In this work, MoS 2 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 MoS 2 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 MoS 2 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 MoS 2 make it an ideal candidate for application in selective MS analysis of the target analyte from complex samples.