filterPeakSatellites {RMassBank} | R Documentation

## Filter satellite peaks

### Description

Filters satellite peaks in FT spectra which arise from FT artifacts and from conversion to stick mode. A very simple rule is used which holds mostly true for MSMS spectra (and shouldn't be applied to MS1 spectra which contain isotope structures...)

### Usage

    filterPeakSatellites(peaks, filterSettings = getOption("RMassBank")$filterSettings)

### Arguments

`peaks` | A peak dataframe with at least the columns `mz, int`. Note that `mz` is used even for the recalibrated spectra, i.e. the desatellited spectrum is identical for both the unrecalibrated and the recalibrated spectra.
`filterSettings` | The settings used for filtering. Refer to `analyzeMsMs` documentation for filter settings.

### Details

The function cuts off all peaks within 0.5 m/z from every peak, in decreasing intensity order, which are below 5 intensity. E.g. for peaks m/z=100, int=100; m/z=100.2, int=2, m/z=100.3, int=6, m/z 150, int=10: The most intense peak (m/z=100) is selected, all neighborhood peaks below 5 peak) and the next less intense peak is selected. Here this is the m/z=150 peak. All low-intensity neighborhood peaks are removed (nothing). The next less intense peak is selected (m/z=100.3) and again neighborhood peaks are cut away (nothing to cut here. Note that the m/z = 100.2 peak was alredy removed.)

### Value

Returns the peak table with satellite peaks removed.

### Note

This is a very crude rule, but works remarkably well for our spectra.

### Author(s)

Michael Stravs

### See Also

`analyzeMsMs`, `filterLowaccResults`

### Examples

    # From the workflow:
    ## Not run:
        # Filter out satellite peaks:
        shot <- filterPeakSatellites(shot)
        shot_satellite_n <- setdiff(row.names(shot_full), row.names(shot))
        shot_satellite <- shot_full[shot_satellite_n,]
        # shot_satellite contains the peaks which were eliminated as satellites.

    ## End(Not run)

[Package RMassBank version 3.2.0 Index]