A novel asymmetrical arc-shaped electrode ion trap for improving the performance of a miniature mass spectrometer.

RATIONALE: The pivotal challenge associated with miniature mass analyzers is their proper design and construction without sacrificing performance. In order to analyze and improve the performance of a miniature linear ion trap with odd and even multipole fields, we designed a novel asymmetrical arc-shaped electrode ion trap (AAEIT), and tested the properties of AAEITs with different dimensions. METHODS: A series of asymmetrical ion traps using arc-shaped electrodes were designed to optimize the properties (resolutions and intensity) of the coupling effects between odd and even multipole fields. Using arginine and reserpine, we evaluated the performance of mass resolution, ion intensity ratio and deduced the collision-induced dissociation (CID) efficiency using a self-constructed electrospray ionization mass spectrometry (ESI-MS) platform. RESULTS: An AAEIT with field radius dimensions of 5 mm × 5.75 mm exhibits a good performance: its maximum resolution of 833 (FWHM) at m/z 175 was achieved for the side of small electrode. With this AAEIT, a tandem mass (MS/MS) capability with 91.0% CID efficiency was obtained with reserpine (m/z 609). CONCLUSIONS: The results indicated that the AAEIT, comprising both odd and even multipole fields, could act as a qualified linear ion trap mass analyzer with compact structure, high resolution, and high tandem mass analysis efficiency. It has a great potential in miniature mass spectrometry.