Neutral Loss Water and Ammonia Fragment Mass Table
Tabulate monoisotopic H2O/NH3 neutral-loss m/z shifts for a stated positive charge; does not predict whether a fragment loses either species.
Description
Tabulate monoisotopic H2O/NH3 neutral-loss m/z shifts for a stated positive charge; does not predict whether a fragment loses either species.
A neutral loss shifts an ion's m/z by the neutral mass divided by its charge. Water and ammonia losses can therefore produce different shifts for multiply charged fragments.
When to use this tool
Tabulate monoisotopic H2O/NH3 neutral-loss m/z shifts for a stated positive charge; does not predict whether a fragment loses either species.
- Prepare the supplied fragmentMz, charge 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 fragmentMz, charge. 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.waterLossMz, result.ammoniaLossMz. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
Require positive fragmentMz and integer charge from one through 100. Subtract 18.01056468403/charge for water and 17.02654910112/charge for ammonia; reject a fragment that would have nonpositive water-loss m/z.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| fragmentMz | fragment mz. | Finite number; greater than zero |
| charge | charge. | Integer from 1 to 100 inclusive |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.waterLossMz | The water loss mz value under the stated formula or text convention. |
| result.ammoniaLossMz | The ammonia loss mz value under the stated formula or text convention. |
{
"input": {
"fragmentMz": 100,
"charge": 2
},
"output": {
"result": {
"waterLossMz": 90.994717657985,
"ammoniaLossMz": 91.48672544944
}
}
}Limitations and assumptions
- These are theoretical shifts for the two fixed neutral masses. No spectrum is analyzed and no loss is established to occur; the tool does not identify a fragment or 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 neutral mass
Monoisotopic neutral peptide mass adds residue masses and one terminal water molecule.
- digest mass filter
Digest mass filtering retains supplied peptides whose calculated neutral masses lie within a chosen interval.