Mass Accuracy PPM

Calculate signed mass error in ppm relative to theoretical m/z.

Description

Mass accuracy expresses a measured-to-theoretical difference relative to theoretical m/z in parts per million.

Mass accuracy expresses a measured-to-theoretical difference relative to theoretical m/z in parts per million. The sign distinguishes high from low observed mass.^[1]

Calculate signed mass error in ppm relative to theoretical m/z.

When to use Mass Accuracy PPM

Use this tool to calculate signed mass error in ppm relative to theoretical m/z.

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 Mass Accuracy PPM 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 observedMz, theoreticalMz, maximumAbsolutePpm using the field table and calculation rules, then run the tool.
Read errorPpm, withinTolerance. 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
observedMz	Observed mz	number	Required
theoreticalMz	Theoretical mz	number	Required
maximumAbsolutePpm	Maximum absolute ppm	number	Required

Enter positive m/z values and nonnegative absolute ppm tolerance. Return signed error and inclusive absolute-error gate.

ppm=1e6(observed−theoretical)/theoretical

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

Output field	Meaning	Value type
errorPpm	Error ppm	number
withinTolerance	Within tolerance	boolean

json

{
  "input": {
    "observedMz": 101,
    "theoreticalMz": 100,
    "maximumAbsolutePpm": 10000
  },
  "output": {
    "errorPpm": 10000,
    "withinTolerance": true
  }
}

Limitations and assumptions

Theoretical assignment, charge state and isotope identity are not checked.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use XIC Mass Window: Plan an extracted-ion m/z window from target mass and ppm tolerance. For a complementary task, use Adduct MZ: Calculate adduct ion m/z from neutral mass, injected mass shift, and charge.

References

Mass Accuracy PPM — tool.io

Similar or alternative tools

XIC Mass Window
Plan an extracted-ion m/z window from target mass and ppm tolerance.
Adduct MZ
Calculate adduct ion m/z from neutral mass, injected mass shift, and charge.