Carryover - Thermo Scientific EASY-nLC 1200 Troubleshooting And Maintenance Manual

Carryover

Table 20. Possible causes of carryover
Symptom
Carryover from one run to the
next
Thermo Scientific
Table 20 lists the possible causes of carryover.
Possible cause
Incomplete elution of peptides
from column
Insufficient washing of needle
and loop
Dead volumes in the column
setup
Figure 133 shows a gradient run with a high-organic hold at the end of the run that is too
short for the column to see the high-organic solvent, as displayed by the lack of a pressure
drop at the end of the run.
Figure 133. Gradient run without an adequate high-organic hold at the end of the run
Action
Add extra time to the end of the gradient or add
a high-organic hold to the end of the gradient.
To determine if the high-organic hold is long
enough, make sure that you see a pressure drop
during the hold period and the pressure reaches a
minimum and maintains it (see
Figure 134).
Add extra wash steps to the method. Consider
using an organic solvent for one of the custom
wash solvents.
Remake the connections in the column setup.
EASY-nLC 1200 Troubleshooting & Maintenance Guide
7
Troubleshooting
Troubleshooting Tips
Figure 133 and
155