Metrohm 883 Basic IC plus Manual page 98

5.1
Problem
The retention times
in the chromato-
gram have changed
unexpectedly.
Peak areas are lower
than expected.
The peristaltic pump
is pumping too little.
90
￭￭￭￭￭￭￭￭
Cause
The conductivity detector is
blocked.
Guard column – Blocked.
Separation column –
Blocked.
Injection valve – blocked.
Eluent - Incorrect concen-
tration
Separation column –
Diminished separating effi-
ciency.
The eluent contains gas
bubbles.
High-pressure pump –
Defective.
Sample – There is a leak in
the sample path.
Sample – The sample path
is blocked.
Sample – The sample loop
is not (completely) filled.
Peristaltic pump – Contact
pressure too weak.
Peristaltic pump – Filter
blocked.
￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
Remedy
Shorten the capillary ends by a few millime-
￭
ters .
Rinse the detector opposite the normal
￭
flow direction .
Replace the guard column (see chapter 3.19,
page 49).
Regenerate the separation column (see
￭
chapter 4.14.4, page 88).
Replace the separation column (see "Con-
￭
necting the separation column", page 53).
Note: Samples should always be microfiltered .
Have the valve cleaned (by a Metrohm service
engineer).
Create eluent with correct concentration.
Regenerate the separation column (see
￭
chapter 4.14.4, page 88).
Replace the separation column (see "Con-
￭
necting the separation column", page 53).
Deaerate the high-pressure pump (see fig-
￭
ure , page 48).
Request Metrohm Service.
Find and fix the leak in the sample path.
Find and eliminate the blockage in the sample
path.
Adjust the transfer time for the sample (see
"Determining the transfer time", page 86).
Correctly set the contact pressure (see "Setting
the contact pressure correctly", page 41).
Replace the filter (see "Replacing the filter",
page 85).
883 Basic IC plus