Abstract

Symposium Sessions

Day 2, June 11（Tue.）　9:15-9:35　Room A (Convention Hall 300)

Although linear time-of-flight (TOF) mass spectrometry (MS) is a low-resolution technique that has very limited applications in modern high-resolution MS, it is still an indispensable tool for analyses in high mass range. Combining TOF mass analyzer with matrix-assisted laser desorption/ionization (MALDI) ion sources is a popular design since other high-resolution instruments cannot offer comparable sensitivity. Through flight-time topological analyses, we can precisely determine the flight-time spread of ions resulted from different instrument design and experimental parameters. The result reveals several unknown facts limiting the performance of such instruments, including the correlation between mass resolving power (MRP) and mass-to-charge ratio, instrument design, electrode voltages, extraction delay, and others. The most essential findings are the critical roles of ion acceleration region of MALDI ion source and the scaling law in linear TOFMS. It indicates that conventional linear TOFMS cannot effectively reduce the impact of ion's initial velocity spread on observed MRP. The effectiveness of the predicted parameters was validated experimentally to be reasonably close to the true optimal values. We have proposed a universal design principle to assist instrumental scientists in developing new instruments with ultimate performance. Some practical limitations in real measurements will also be discussed.

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