In the UNIFI MSe High Energy spectrum, the spectrum is detected in the higher molecular region, over the precursor ion - WKB190865

SYMPTOMS

• In the MSe High Energy spectrum, the spectrum is detected in the higher molecular region over the precursor ion
• Due to the broadening of peaks, retention time of precursor ion on XIC acquired with MSe Low Energy and retention time of fragment ion on XIC acquired with MSe High Energy are slightly different

ENVIRONMENT

• UNIFI
• Pathway profiling - MSe

CAUSE

A spectrum derived from another compound generated at the same retention time as the precursor ion is mixed.

FIX or WORKAROUND

• Set the allowable deviation of the retention time used to associate the precursor ion and the product ion to a small value.

• Set in Analysis method > Peak Processing Settings > 3D Isotope Clustering,

  “Fraction of the chromatographic peak width to apply during high to low energy association”

  For example, if you set it to 0.1

  Against the half width of the mass chromatogram peak of precursor ion,

  fragment ion with a retention time within 0.1 (10%) deviation are associated.

ADDITIONAL INFORMATION