Quadrupole Mass Filter Model

This page is for the use of Reliance's Quadrupole Mass Filter (QMF) simulation program. The simulator is made freely available by Reliance as a service to the mass spectrometry community.

Quadrupole Diagram

The model calculates mass spectrum peak shape for a QMF specified by the user. The simulation program solves numerically an autonomous set of ODEs derived from the Mathieu equation. Ions are injected into the QMF, at the entrance, parallel to the Z-axis, in a round beam, their trajectories are then calculated through the QMF. The exit of the filter is a circular aperture and only ion trajectories that pass through the aperture are regarded as having been detected. Several million ion flights are calculated in a Monte-Carlo simulation to determine the aggregate mass peak shape.

The following assumptions are made in the model:-

  • There are no fringing fields at the entrance and exit of the QMF.
  • There is no electric field in the Z direction
  • The ion source provides a non divergent, uniformly illuminated round beam.
  • Ion detection occurs when the ion passes through the exit aperture.
  • The electrodes are of hyperbolic form.

To use the model simply enter your parameters into the boxes below, along with your name, email address and organisation. Then press submit and your results will be emailed to you.

Simulation is performed on a cluster of ten high-specification PCs and while computation times vary depending upon the exact model parameters chosen, a result can be expected within the hour. The model is limited to a maximum mass of 2000Da. and maximum QMF length of 300mm to preserve resources.

The model is a reduced version of Reliance's full QMF model. The full model is capable of simulating the effects of imperfect quadrupole geometry which give rise to limited resolution and peak shape degradation. For more information on modelling with the full model contact us.

Mass Filter Dimensions
Inscribed Radius metres (range: 0.0001m - 0.02m)
Length metres (range: 0.01m - 0.3m)
Exit Aperture Diameter metres (range: 0.0001m - 0.02m)
Mass Filter Scan
Excitation Frequency Hertz (range: 1000Hz - 100MHz)
Resolution (0.75 gives approximate unit mass resolution)
Ion Source
Ion Energy electron Volts (range: 0.1eV - 50eV)
Ion Mass Daltons (range: 1Da - 2000Da)
Source Temperature Kelvin (range: 0K - 2000K)
Beam Diameter metres (range: 0.0001m - 0.02m)
Submission Details

Title
Organisation or Company
Email Address

Please note that due to the assumptions made by the model Reliance cannot guarantee that the model suits your application and the results generated by the model may not necessarily match those of an actual QMF system.