Mass spectrometry apparatus and methods

摘要

A mass spectrometer having a mass filter which applies a transient voltage profile to accelerate ion packets. The voltage profile is chosen to have a functional form which imparts each ion species with a kinetic energy which is larger the larger the mass-to-charge ratio and a velocity which is smaller the larger the mass-to-charge ratio. The ions are detected in an ion detector which discriminates between different ion species based on their kinetic energy and taking account of the functional form of the voltage profile. Suitable voltage profiles include periodic functions such as sinusoids, triangles and sawtooths, which allow the amplification of drive pulses in the mass filter to be carried out with narrow band amplification stages, which are simple and inexpensive to construct.

主权项

1. A mass spectrometer comprising:
an ion source configured to provide ion packets on demand, each comprising a plurality of ions with mass-to-charge ratios, those ions with a common mass-to-charge ratio being referred to as an ion species; a mass filter having a length and comprising an electrode arrangement arranged to receive the ion packets from the ion source, and a drive circuit operable to apply a time-varying voltage profile to the electrode arrangement such that the ions of the received ion packets travel the length of the mass filter through a spatially uniform time-varying electric field, wherein the voltage profile has a functional form which imparts each ion species with a kinetic energy which is larger the larger the mass-to-charge ratio and a velocity which is smaller the larger the mass-to-charge ratio; and an ion detector arranged to receive the ions output from the mass filter and operable to discriminate between different ion species based on their kinetic energy and taking account of the functional form of the voltage profile.