A bimetallic delafossite structured material (AgFeO2) has been prepared and modified with chitosan, ‘AgFeO2@CTS’. It has been shown to be an effective nanoparticle for biothiol separation and surface for surface assisted laser desorption/ionization mass spectrometry (SALDI–MS). SALDI–MS displays a clear background compared to the conventional MALDI–MS. We believe that these new materials have a promising application in the near future for biothiol separation and applications for SALDI–MS.