Isotopologue Distribution

Normalize M+0 through M+n isotopologues and count mean labeled carbons.

Description

An isotopologue distribution normalizes supplied signals for zero through n labeled carbon positions.

An isotopologue distribution normalizes supplied signals for zero through n labeled carbon positions. Its mean is the expected labeled count under those fractions.^[1]

Normalize M+0 through M+n isotopologues and count mean labeled carbons.

When to use Isotopologue Distribution

Use this tool to normalize M+0 through M+n isotopologues and count mean labeled carbons.

Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.

How to use Isotopologue Distribution and understand its results

Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.
Enter isotopologueCounts, carbonSites using the field table and calculation rules, then run the tool.
Read fractions, meanLabeledCarbons. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
isotopologueCounts	Isotopologue counts	list of number	Required
carbonSites	Carbon sites	number	Required

Enter nonnegative safe integer carbon-site count and exactly n+1 nonnegative signals with positive sum. Return fractions in increasing label-count order and mean labeled atoms.

fraction_i=signal_i/Σsignal; meanLabels=Σi×fraction_i

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
fractions	Fractions	list of number
meanLabeledCarbons	Mean labeled carbons	number

json

{
  "input": {
    "isotopologueCounts": [
      20,
      30,
      50
    ],
    "carbonSites": 2
  },
  "output": {
    "fractions": [
      0.2,
      0.3,
      0.5
    ],
    "meanLabeledCarbons": 1.3
  }
}

Limitations and assumptions

No natural-abundance correction or labeling mechanism is inferred. Signals may be fractional.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Isotope Abundance Correction: Invert a two-isotopologue natural-abundance correction matrix. For a complementary task, use MPLUS1 Carbon Estimate: Estimate carbon number from M+1 intensity using a caller-supplied per-carbon isotope contribution.

References

Isotopologue Distribution — tool.io

Similar or alternative tools

Isotope Abundance Correction
Invert a two-isotopologue natural-abundance correction matrix.
MPLUS1 Carbon Estimate
Estimate carbon number from M+1 intensity using a caller-supplied per-carbon isotope contribution.