A radio frequency power supply for the quadrupole with prefilters

Abstract

A mass analyzer is the core component of a mass spectrometer (MS). As one of the mass analyzers, the quadrupole varies the electric field and uses the difference in the mass-to-charge ratio of input ions to filter them. The quadrupole is driven by a radio frequency (RF) power supply composed of two reverse high-voltage and high-frequency signals. However, the traditional quadrupole is plagued by the fringing field effect and chemical pollution. This paper proposes a novel pre-quadrupole RF power frame to achieve a wide range of mass-to-charge ratio scanning. Quadrupole with prefilters is considered to promote ion focusing and improve ion transmission. This also solves the main filter's pollution problem and the perturbing effect of the fringing field. An RF power supply for this quadrupole is designed consisting of a power amplifier module, an RF resonance module, a feedback circuit module, and a direct current (DC) module. For a resonance frequency of 1 MHz and a scanning frequency of 10 Hz, the designed quadrupole RF power supply's peak-to-peak output voltage reached 2.4 kV in practical tests with negligible fluctuations. Compared to the traditional quadrupole RF power supply, the designed power supply had a higher scanning range and a smaller size with an average power consumption of only 24 W.