Adduct Search

Description

Definition of an adduct ion

An ion formed by interaction of two species, usually an ion and a molecule, and often within the ion source, to form an ion containing all the constituent atoms of one species as well as an additional atom or atoms.

This method identifies common adducts (selected by the user) in a single peak list. The adducts are identified by two conditions:

MZmine has a built-in list of common adducts and their masses. The user can add custom adducts either individually or by loading them from a file. Once custom adducts have been added or loaded they will become part of the application configuration and don't have to be added/loaded again.

The following figure shows a spectrum with a phosphate adduct ion.

The following figure shows a peak list after identifying two "Deuterium" adducts.

Method parameters

RT tolerance
Maximum permissible difference in retention time to set a relationship between peaks
Adducts
List of adducts, each refers a specific m/z difference between related peaks
m/z tolerance
Tolerance value of the m/z difference between peaks
Max adduct peak height
Maximum height of the recognized adduct peak, relative to the main peak

Adduct choices

The figure below shows the Adduct Search parameters dialog. Beside the list of adducts are four buttons that function as follows:

All
Selects all of the check-boxes in the list of adducts.
Clear
Clears the check-boxes in the list of adducts.
Add...
Allows the user to specify an individual custom adduct. A dialog is displayed in which the user can enter the name and mass difference of the new adduct.
Import...
Loads custom adducts from a comma-separated values (CSV) file. The file should be formatted with one adduct defined per line, with each line having the adduct's name and mass difference values separated by a comma.
Export...
Saves the adducts to a comma-separated values (CSV) file.
Reset
Restores the list of adducts to the original default set.