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Target lists

A target list contains the definitions of peaks to be extracted in terms of retention time and mz value. The important parameters for MINT are rt_min and rt_max. The rt value is only used as an estimate and used for comparison. You should know, from former identification runs, at what retention time to expect a certain metabolite. This is what rt is for. For the final extraction process however rt_min and rt_max are used. Before you process the MS files, you should check that all targts have rt_min and rt_max properly set.

Target list format

The target list is the determining protocol for the data processing step. You can reproduce all results using this list as input. A target list can be provided as csv (comma separated values) or xlsx (Microsoft Excel) file.

If the preaklist is provided as multi-sheet xlsx file the target list should be the first sheet.

The input files contains a number of columns headers in the target list should contain:

  • peak_label : A unique identifier such as the biomarker name or ID.
  • mz_mean : The target mass (m/z-value) in [Da].
  • mz_width : The width of the peak in the m/z-dimension in units of ppm. The window will be mz_mean +/- (mz_width * mz_mean * 1e-6). Usually, a values between 5 and 10 are used.
  • rt : Estimated retention time (optional, see above), for reference and used in automated peak optimization.
  • rt_min : The start of the retention time for each peak.
  • rt_max : The end of the retention time for each peak.
  • rt_unit : Time unit can be min (minutes) or s (seconds), Mint will always convert the values to seconds.
  • intensity_threshold : A threshold that is applied to filter noise for each window individually. Can be set to 0 or any positive value.

Example file

target.csv:

peak_label,mz_mean,mz_width,rt_min,rt_max,intensity_threshold
Biomarker-A,151.0605,10,4.65,5.2,0
Biomarker-B,151.02585,10,4.18,4.53,0

A template can be created using the GUI:

  1. Go to the targets tab.
  2. Click on EXPORT to download a target.csv file with all necessary columns.