Design and Application of a Traveling Wave Pulse Power Supply for Traveling Wave Ion Mobility Spectrometry

Ion mobility (IM) coupled mass spectrometry (MS) is a versatile tool for analytical separations, characterization, and detection by measuring collision cross-sections and mass-to-charge (m/z) ratios. Traveling wave (TW)-based structures for lossless ion manipulations (TW-SLIM) is an innovative ion drift tube for complex gas phase ion manipulations, which is the key component of traveling wave ion mobility spectrometry (TWIMS). TW-SLIM combines flexible ion path design and traveling wave technology. The traveling wave pulse power supply is used to provide an oscillatory electric fields. Ions in TWIMS are propelled and separated by traveling wave. The operating pressure, TW amplitude and TW frequency of TW pulse have effect on ion motion in TWIMS. In this work, a traveling wave pulse power supply was developed, which mainly consisted of field programmable gate array (FPGA), halfbridge gate driver integrated circuit (IC), metaloxidesemiconductor field effect transistor (MOSFET), adjustable high voltage module and external trigger signal. The frequency of TW pulse power supply was up to 100 kHz, both rising edge and falling edge were less than 20 ns. The influence of TW amplitude and TW frequency on ions transmission and separation was explored on the home-built instrument platform. The experimental results presented here provide a fundamental understanding of the transmission and separation mechanism in TWIMS. The maximum signal intensity of hexakis (2, 2-difluoroethoxy) phosphazene was at amplitude of 35 V and frequency of 10 kHz. As the traveling wave frequency increased at a fixed traveling wave amplitude, signal intensity of hexakis (2, 2difluoroethoxy) phosphazene decreased. Ions separations was positively related to frequency when traveling wave amplitude was fixed, while traveling wave amplitude was opposite. The development of traveling wave pulse power supply is valuable for research and development of high resolution TWIMS instrument.