Waters ACQUITY UPLC M-Class System Manual page 71

Suspected cause
Incorrect diluent makeup
Column conditioning or re-equilibration
problem
Insufficient trapping
Insufficient initial sample preparation
Interrupted spray
Bad trap column
4.3.2.11 Negative peaks
Suspected cause
Solvent front at the beginning of the
chromatogram at column void volume
Signal cables connected improperly (analog
only)
Loss of spray
4.3.2.12 Split or double peaks
Suspected cause
Injection volume or sample concentration is too
high; disrupting column equilibration.
Sample diluent is too high in organic for the
initial mobile phase.
Possible solution
Confirm the diluent used for preparing the
sample.
Ensure that the column is adequately
conditioned or equilibrated.
Refer to the laboratory sample preparation
protocol.
See also:
Installation and Maintenance Guide.
Replace the column.
Possible solution
Make the sample diluent similar to the initial
mobile phase.
Reset signal polarity, ensuring that you match
positive and negative connections. Refer to the
component overview and maintenance guides
on the documentation CD for specific signal
connection information.
Troubleshoot the loss of spray.
See also:
Installation and Maintenance Guide.
Possible solution
Reduce the injection volume or reduce the
percentage of organic in the diluent.
November 26, 2019, 715003588 Revision C
Page 71
• Confirm the inlet method parameters.
• Confirm that the trapping column is
trapping peptides efficiently.
The Universal NanoFlow Sprayer
The Universal NanoFlow Sprayer
• Reduce the injection volume.
• Dilute the sample.