I've noticed an issue with the side chains for the insilico TGs. As can be seen in the screen shots below, the first three compounds that show up have different side chains but show the exact same MS/MS fragments. This issue seems to repeat every three compounds (groups of three). This issue is not present every time, but fairly often. This is with version 4.38.
Thanks Bryan, we will check it soon.
Hiroshi
Hi Bryan,
my staff has checked this feature.
These are not the exactly same fragments but the slightly different spectra as the decimal values.
I just pasted the detail of MS/MS spectra for these metabolites.
NAME: TG O-16:0_10:0_16:0
PRECURSORMZ: 726.697
PRECURSORTYPE: [M+NH4]+
IONMODE: Positive
FORMULA: C45H88O5
SMILES: O=C(OCC(OC(=O)CCCCCCCCCCCCCCC)COCCCCCCCCCCCCCCCC)CCCCCCCCC
INCHIKEY: FKBSAQBKXJSFMO-UHFFFAOYSA-N
COMPOUNDCLASS: EtherTG
RETENTIONTIME:
COMMENT:
Num Peaks: 5
726.697001 100
709.670452 50
537.524122 999 "NL of SN3 [3]"
467.409487 999 "NL of SN1 [1]"
453.430222 999 "NL of SN2 [2]"
NAME: TG O-17:0_10:0_15:0
PRECURSORMZ: 726.697
PRECURSORTYPE: [M+NH4]+
IONMODE: Positive
FORMULA: C45H88O5
SMILES: O=C(OCC(OC(=O)CCCCCCCCCCCCCC)COCCCCCCCCCCCCCCCCC)CCCCCCCCC
INCHIKEY: DDYDVVZXHMHMOL-UHFFFAOYSA-N
COMPOUNDCLASS: EtherTG
RETENTIONTIME:
COMMENT:
Num Peaks: 5
726.697001 100
709.670452 50
537.524122 999 "NL of SN3 [3]"
467.445872 999 "NL of SN2 [2]"
453.393837 999 "NL of SN1 [1]"
NAME: TG O-11:0_15:0_16:0
PRECURSORMZ: 726.697
PRECURSORTYPE: [M+NH4]+
IONMODE: Positive
FORMULA: C45H88O5
SMILES: O=C(OCC(OC(=O)CCCCCCCCCCCCCCC)COCCCCCCCCCCC)CCCCCCCCCCCCCC
INCHIKEY: KXAAUHFLKJXVON-UHFFFAOYSA-N
COMPOUNDCLASS: EtherTG
RETENTIONTIME:
COMMENT:
Num Peaks: 5
726.697001 100
709.670452 50
537.487737 999 "NL of SN1 [1]"
467.445872 999 "NL of SN2 [2]"
453.430222 999 "NL of SN3 [3]"
Currently, the intensity differences for cleaving ether and ester linkages are not defined, and therefore, those spectra look very similar. And it indicates that currently it's very difficult to distinguish them unless we can use very high resolution/accuracy MS instrument for MS2!
Thanks,
Hiroshi
Thank you! This clears it up.