Pekatable filter

Peaktable filters

The peaktable filters are a set of operation that you can specify which will be apply on all your peaktable before alignment. This is especially useful if you:

1. Encounter processing issues and your gradient is very long.
2. Only want a very fast processing to pick the main features.
3. Want to discard the beginning or the end of the gradient. All these filter need to be applied into the peakpicking/peaktable_filter arguments, a filter is composed of 4 elements:

[METRIC][OPERATOR][VALUE]

For example by default to pick the 30000 most intense peaks the filter is absolute_intensity top 30000. A command to remove the peak eluting before 2 mins and after 20 would be: rt greater 2 & rt lower 20 Authorized values for the different elements are:

• METRICS:

  • absolute_intensity: Peak area in absolute value
  • relative_intensity: Peak area in relative value
  • absolute_height: Peak height in absolute value
  • relative_height: Peak height in relative value
  • SN: Signal-to-noise as measured by the peakpicking algorithm used
  • peakwidth: The measured peakwidth.
  • mz: The mass-to-charge
  • rt: The retention time

• OPERATOR:

  • greater: Select features with METRIC greater than VALUE.
  • lower: Select features with METRIC lower than VALUE.
  • equal: Select features with METRIC equal to VALUE.
  • top: Select the VALUE features with the top METRIC values.
  • bottom: Select the VALUE features with the bttom METRIC values.

• VALUE: Any numeric value, only integer for top or bottom and and float for greater and lower.