Mass-Spectrometric Observation of C+ Ions during Electrospray with In-Source Atomization

Carbon C+ ions formed in a mass-spectrometric electrospray source with controlled in-source fragmentation and atomization interface have been observed for the first time. The measurements were performed in a special MI-20 LowMass mass spectrometer (MS-Bio LLC) using aqueous methanol solutions of lithium and beryllium salts. The peak of C+ ions was substantially broadened as compared to the peaks of metal ions. A model is proposed that explains the formation of C+ ions due to charge exchange immediately at the high-vacuum boundary near the skimmer output.