Waters ACQUITY UPLC M-Class - Page 71

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