Formula prediction
Description
This module attempts to calculate all possible molecular formulas for every peak in the peak list,
using given elemental and heuristic constraints. For a detailed description of the
functionality and the embedded algorithms, please see the following publication:
Pluskal T. et al, Highly Accurate Chemical Formula Prediction Tool Utilizing High-Resolution Mass
Spectra, MS/MS Fragmentation, Heuristic Rules, and Isotope Pattern Matching.
Anal Chem (2012), 84(10):4396-403.
Method parameters
- Charge
- The neutral mass is calculated from the peak m/z value, its charge and type of ionization adduct.
- Ionization type
- The neutral mass is calculated from the peak m/z value, its charge and type of ionization adduct.
- m/z tolerance
- Tolerance of the neutral mass for searching the formula.
- Elements
- Elements allowed in the formula and their minimum and maximum counts.
- Element count heuristics
- Selection of heuristic restrictions on element counts.
- RDBE restrictions
- Selection of restrictions on RDBE (rings double bonds) values. .
- Isotope pattern filter
- If selected, only results which fit the required isotope pattern similarity score will be returned.
- MS/MS filter
- Restrict the formulas to those that can be interpreted in the peak's MS/MS pattern.