Why is the "Mass Confirmed" check box not selected in the Review pane of Glycan (FRL with MS confirmation) analysis? - WKB94623

ENVIRONMENT

• UNIFI
• Glycan (FLR with MS Confirmation)

ANSWER

In Glycan Assay (FLR with MS Confirmation), UNIFI software assigns the glycan with the closest mass value to that of the observed peak (see Help file "View glycan results"). However, in order for the "mass confirmed" check box to be selected, the accuracy of the mass match must meet the criteria specified in the Target By Mass settings of the analysis method. For example, if the best mass match in the glycan library is 1.3534 m/z different from the observed mass, and the expected m/z is 1745.6733, the delta m/z is 10⁶  X 1.3435/1745.6733 = 775 ppm. The default value for the "Target By Mass" criteria setting in the analysis method is 10 ppm. So although the glycan with m/z 1747.0168 is the best match in the library for the observed peak, it does not meet the "target by mass" criteria. The FLR identification cannot be considered to be confirmed by the mass match. Hence, the check box is clear.

ADDITIONAL INFORMATION