Custom database search

Description

This method assigns identity to peaks according to their m/z and retention time values. The user provides a database of m/z values and retention times in CSV format (see below).

Method parameters

Database file
Name of file that contains information for peak identification
Field separator
Character(s) used to separate fields in the database file
Field order
Order of items in which they are read from database file. Order may be changed by dragging the items with mouse.
Ignore first line
Check to ignore the first line of database file
m/z tolerance
Maximum allowed m/z difference to set an identification to a peak
RT tolerance
Maximum allowed retention time difference to set an identification to a peak

Database file

Database file has to be provided in CSV format (Comma-Separated Values). Such files can be exported from a spreadsheet software such as MS Excel, or edited manually using a text editor. The following examples shows the structure of the database file:

ID,m/z,Retention time (min),Identity,Formula
1,175.121,24.5,Arginine,C6H14N4O2
2,133.063,11.9,Asparagine,C4H8N2O3
3,134.047,11.7,Aspartate,C4H7NO4

If the m/z value or Retention time value in the CSV file is 0, then the value is considered as a wild card. E.g, the following item will match all peaks of 174.121 m/z without considering the retention time:

1,175.121,0,Arginine,C6H14N4O2

Setup dialog for the identification using the above example database file: