getformula: Get chemical formula for mass to charge ratio using the...

In enviGCMS: GC/LC-MS Data Analysis for Environmental Science

Get chemical formula for mass to charge ratio using the HORIZON algorithm

Description

Rapidly decomposes accurate mass-to-charge ratios into candidate chemical formulas using the native HORIZON (Heavy-first Ordered Recursive Inference with Zero-loop Optimal Navigation) engine. Supports chemical plausibility filtering via Double Bond Equivalents (DBE), Nitrogen rule, and Kind & Fiehn Seven Golden Rules.

Usage

getformula(
  mz,
  charge = 0,
  window = 0.001,
  elements = list(C = c(1, 50), H = c(1, 50), N = c(0, 50), O = c(0, 50), P = c(0, 1), S
    = c(0, 1)),
  golden_rules = TRUE,
  detailed = FALSE,
  resolution = 0,
  nthreads = 1
)

Arguments

mz	a vector with mass to charge ratio
charge	The charge value of the formula, default 0 for autodetect
window	The window accuracy in the same units as mass
elements	Elements list to take into account.
golden_rules	logical, whether to filter by Fiehn Seven Golden Rules (default: TRUE)
detailed	logical, if TRUE return a list of data.frames with formula, exact mass, error, DBE, H/C ratio, Senior rules, and validation details; if FALSE (default), return a list of character vectors of valid formulas
resolution	numeric, mass spectrometer resolving power for isotope peak merging (default: 0)
nthreads	integer, number of OpenMP parallel threads for batch processing (default: 1)

Value

list of chemical formulas (or data.frames if detailed = TRUE)

enviGCMS documentation built on Oct. 10, 2026, 5:06 p.m.