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.
Description
Add the proton mass for an independently established singly protonated neutral peptide; not a sodium adduct or a multiply charged m/z.
Adding a proton to a neutral mass gives the m/z of a singly protonated ion under a stated mass convention. It differs from adding a neutral hydrogen atom.
When to use this tool
Add the proton mass for an independently established singly protonated neutral peptide; not a sodium adduct or a multiply charged m/z.
- Prepare the supplied neutralMassDa 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 neutralMassDa. 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.singlyProtonatedMz. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Require neutralMassDa greater than zero and return neutralMassDa+1.007276466621 as singlyProtonatedMz.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| neutralMassDa | neutral mass da. | Finite number; greater than zero |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.singlyProtonatedMz | The singly protonated mz value under the stated formula or text convention. |
{
"input": {
"neutralMassDa": 100
},
"output": {
"result": {
"singlyProtonatedMz": 101.007276466621
}
}
}Limitations and assumptions
- The calculation assumes one proton and unit positive charge. It does not handle other adducts, multiple charges, isotopic envelopes or mass measurement uncertainty.
- 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 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.
- peptide mass error dalton
Mass error compares an observed mass with a theoretical reference in daltons.