Peptide ppm Mass Error Observed versus Theoretical Calculator
Compute signed relative peptide mass error against the theoretical mass; not an absolute-error replacement or a match-confidence score.
Description
Compute signed relative peptide mass error against the theoretical mass; not an absolute-error replacement or a match-confidence score.
Signed mass error states whether an observed mass lies above or below its theoretical reference. Scaling by the theoretical mass expresses the discrepancy in parts per million.
When to use this tool
Compute signed relative peptide mass error against the theoretical mass; not an absolute-error replacement or a match-confidence score.
- Prepare the supplied observedMassDa, theoreticalMassDa fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter observedMassDa, theoreticalMassDa. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.signedErrorPpm. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Require both masses positive and compute 1,000,000*(observedMassDa-theoreticalMassDa)/theoreticalMassDa.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| observedMassDa | observed mass da. | Finite number; greater than zero |
| theoreticalMassDa | theoretical mass da. | Finite number; greater than zero |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.signedErrorPpm | The signed error ppm value under the stated formula or text convention. |
{
"input": {
"observedMassDa": 100.001,
"theoreticalMassDa": 100
},
"output": {
"result": {
"signedErrorPpm": 10
}
}
}Limitations and assumptions
- Use the same mass definition and unit for both inputs. The tool does not infer charge, isotope assignment or a pass/fail tolerance, and an error does not identify a peptide.
- Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
- Ordinary string lists have at most 128 entries of at most 128 code units each; numeric lists and matrices have separate bounded size checks. Nonfinite results and excessively large serialized outputs are rejected.
- Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.
Alternative or Complementary methods
Use compatible mass, charge and sequence conventions when combining these operations. Inspect experimental spectra or quantitative controls separately; sequence features and theoretical mass arithmetic are not peptide identification or biological interpretation.
References
Similar or alternative tools
- peptide mass error dalton
Mass error compares an observed mass with a theoretical reference in daltons.
- Protonated Peptide M-plus-H Mass Calculator
Add the proton mass for an independently established singly protonated neutral peptide; not a sodium adduct or a multiply charged m/z.