Sequential Formation of Analyte Ions Originated from Bulk Alloys for Ambient Mass Spectrometry Analysis.

Rapid chemical decoding of bulk alloys to obtain both organic and elemental composition is of sustainable interest in multiple disciplines. Herein, an analytical strategy inherited from electrochemistry and mass spectrometry (MS) was developed for direct molecular characterization of alloys. While the organics on the alloy surface were simply extracted into the solvent for ESI-MS analysis, the components in the bulk alloy were successively converted into metal ions at appropriate electrolysis potentials, which were online chelated with specific ligands for ESI-MS analysis. A single sample analysis took only a few seconds since no other sample pretreatment was required, and a detection limit of 0.1 ppb was achieved for a component in alloy with low sample consumption (<1.0 mg). Proof-of-concept application indicated that the presented method has unique capability for successive analysis of organic and metallic components in liquids (e.g., engine oil), solids (e.g., alloy), and tunable spatial resolution (∼1.0 to (1.0 × 10-5) cm2) for molecular characterization of bulk alloys.