Previous Next

*   Smoothing
The Mass Frontier application performs smoothing to average ion profiles (not the total ion chromatogram) for every ion (m/z value) found in the data file with their neighbors in a time series. Smoothing can increase correct component detection and eliminate spikes, which cause false positive results. For additional information, see Using Components Detection and Spectra Deconvolution.
v
To apply smoothing to your data
1.
Click the Chromatogram Processing Utilities button, , and choose Smoothing.
The Smoothing dialog box opens.
2.
3.
Click Calculate.
4.
Smoothing dialog box
Specifies the mass difference within which the algorithm merges spectral peaks into one m/z value. A low value might result in more components (oscillating ions) and a high value can result in fewer components (merging ions).
Applies smoothing only to MS1 stage (full scan).
Divides the chromatogram into discrete parts so that the software can apply separate algorithms to each part. This option can provide better results if the chromatogram exhibits diverse shape, peak density, and baseline characteristics in the retention time scale. Avoid segmentation if using a LOESS or Median filter or if results obtained without segmentation are acceptable.
This list includes the following smoothing methods: Savitzky-Golay, Median, and LOESS. In contrast to Median and LOESS methods, the Savitzky-Golay method requires time-equidistant scans.
Smooths each ion profile in the chromatogram using the Median filter. The Length parameter determines the filter length.
Smooths each ion profile in the chromatogram using the Savitzky-Golay filter. The Length parameter determines the filter length.
This smoothing requires equidistant time steps between scans. If smoothed results are not acceptable, use another method or check segmentation.
Smooths each ion profile in the chromatogram using the LOESS filter. The Length parameter determines the filter length. This filter works in a similar way as the Savitzky-Golay filter but is slower and does not require equidistant time steps between scans. When Robust Smoothing is on, then the smoothing is slower but more robust to outlier data in ion profiles.
Opens the Save Smoothing Parameters File dialog box where you save your current parameters to a smoothing parameters file (.smooth.par).
Opens the Open Smoothing Parameters File dialog box where you can choose a smoothing parameters file (.smooth.par) to load.
 
Smoothing wizard dialog box
Specifies the mass difference within which the algorithm merges spectral peaks into one m/z value. A low value might result in more components (oscillating ions) and a high value can result in fewer components (merging ions).
Applies smoothing only to MS1 stage (full scan).
Divides the chromatogram into discrete parts so that the software can apply separate algorithms to each part. This option can provide better results if the chromatogram exhibits diverse shape, peak density, and baseline characteristics in the retention time scale. Avoid segmentation if using a LOESS or Median filter or if results obtained without segmentation are acceptable.
This list includes the following smoothing methods: Savitzky-Golay, Median, and LOESS. In contrast to Median and LOESS methods, the Savitzky-Golay method requires time-equidistant scans.
Smooths each ion profile in the chromatogram using the Median filter. The Length parameter determines the filter length.
Smooths each ion profile in the chromatogram using the Savitzky-Golay filter. The Length parameter determines the filter length. This smoothing requires equidistant time steps between scans. If smoothed results are not acceptable, use another method or check segmentation.
Smooths each ion profile in the chromatogram using the LOESS filter. The Length parameter determines the filter length. This filter works in a similar way as the Savitzky-Golay filter but is slower and does not require equidistant time steps between scans. When Robust Smoothing is on, then the smoothing is slower but more robust to outlier data in ion profiles.
Opens the Save Smoothing Parameters File dialog box where you save your current parameters to a smoothing parameters file (.smooth.par).
Opens the Open Smoothing Parameters File dialog box where you can choose a smoothing parameters file (.smooth.par) to load.


Previous Next
Related Topics:
  Fragment Ion Search (FISh)
  Force Mass Tolerance
  Matrix Conversion
  Thresholding
  Baseline Correction and Noise Elimination
  Base Peak Chromatogram
  Background Subtraction
Copyright 1998 - 2013 HighChem Ltd., Slovakia