FormulaM

Enumerate candidate formulas from observed m/z, explicit charge, tolerance, element bounds, and isotope restrictions.

Search inputs

Observed m/z Explicit charge Examples: +1, 1+, +2, 2+, -1, 2- Tolerance mode Tolerance ppm Tolerance Da Max results

Use one row per isotope-specific species. Repeated elements are allowed when different isotopes are selected.

Element	Isotope	Lower limit	Upper limit

formula	ion_formula	charge	neutral_mass	predicted_mz	error_da	error_ppm

Input examples

Singly charged glucose-like search: m/z=180.06338810418, charge=+1, rows C 0-12, H 0-30, O 0-12.
Doubly charged ion: m/z=90.03169405209, charge=+2, rows C 0-12, H 0-30, O 0-12.
Force boron-11: row B, isotope 11B, limits 1-1; row H, default isotope, limits 4-4; m/z=15.04060529592.