Inconsistent peak areas and intensities in chromatography from LC-MS - WKB239361

SYMPTOMS

• Chromatographic peaks show more variation in area and intensity than is acceptable
• Peak area reproducibility is unacceptable
• Peak shapes can look square-topped and are an odd shape

ENVIRONMENT

• Xevo TQ-S
• QDa
• Xevo TQ-S micro

CAUSE

Inappropriate dwell time (or scan frequency on the QDa) set in the MS method leads to too few data points per peak. This can be caused by too many overlapping functions in the method.

FIX or WORKAROUND

1. Measure points per peak in MassLynx (see below).
2. Correct the dwell time.

ADDITIONAL INFORMATION

A dwell time too long leads to an insufficient number of points per peak; 15 are required for proper consistency.

How to measure points per peak in MassLynx - WKB6042

The number of points per peak can also be increased by separating out overlapping functions in the method by setting time windows for each function.