MSP Standardizations
Libraries usually use various terminologies for the same properties. IDSL.FSA is able to merge the alternative names of meta-variables from different libraries into a meta-variable described below. Please let us know if you have more suggestions for library standardization.
| Metavariable | alternative name 1 | alternative name 2 | alternative name 3 |
|---|---|---|---|
| retention_time | retentiontime | precursorrt | precursor_rt |
| precursor_intensity | precursorintensity | precursorint | precursor_int |
| precursor_type | precursortype | ||
| ms_level | mslevel | spectrumtype | spectrum_type |
| accession | db# | ||
| collision_energy | collisionenergy | ce | energy |
| instrument_type | instrumenttype | ||
| ion_mode | ionmode | ||
| exact_mass | exactmass |
IDSL.FSA has an option to match library fragmentation patterns based on precursor types. In many cases, precursor types from NIST, GNPS, and MoNA libraries are similar in the nature but different in the presentation terms; therefore, to minimize automation errors, IDSL.FSA deconvolutes the entire precursor types and then regenerate them according to the Standard Adduct Type suggested by the IDSL.UFA pipeline. However, a number of precursor type terms can not be corrected unless a brute-force character replacement method is implemented. Hence, IDSL.FSA replaces the the following terms with standard IUPAC formulas in the precursor types from Fiehn's lab adduct list.
| Online Libraries | Standard format |
|---|---|
| space | blank |
| period(.) | blank |
| asterik(*) | blank |
| Cat | M + H |
| ACN | C2H3N |
| TFA | C2HF3O2 |
| FA | CH2O2 |
| formate | CHO2 |
| MeOH | CH3OH |
| Hac | C2H3O |
| IsoProp | C3H8O |
| DMSO | C2H6OS |
| [M]-- | [M]2- |
| [M]++ | [M]2+ |
| [M]1- | [M]- |
| [M]1+ | [M]+ |
| +9i | blank |
| +8i | blank |
| +7i | blank |
| +6i | blank |
| +5i | blank |
| +4i | blank |
| +3i | blank |
| +2i | blank |
| +i | blank |
| -9i | blank |
| -8i | blank |
| -7i | blank |
| -6i | blank |
| -5i | blank |
| -4i | blank |
| -3i | blank |
| -2i | blank |
| -i | blank |
IDSL.FSA also attempts to adjust the formal charge of ions for less complex adduct types similar to the IDSL.UFA Standard Adduct Type. When the formal charge is not adjustable, the original formal charge is still used to match precursor types.