Metrohm 930 Compact IC Flex ChS/Deg Manual page 97

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Problem
Extreme spread of
the peaks in the
chromatogram.
Splitting (dual
peaks)
Precision problems -
the measured values
are highly scattered.
Vacuum is not being
built
930 Compact IC Flex ChS/Deg (2.930.1260)
Cause
Capillary connections –
Dead volume in the sys-
tem.
Guard column – Dimin-
ished efficiency.
Separation column – Dead
volume at the column
head.
Injection valve – Sample
loop.
Sample – There are gas
bubbles in the sample.
Sample – The rinsing vol-
ume is too small.
Injection valve – Defective.
Eluent degasser – Vacuum
connection on the rear of
the instrument is not
(tightly) sealed.
Remedy
Check the capillary connections (see Chapter
3.2, page 14) (use PEEK capillaries with an
inner diameter of 0.25 mm between the injec-
tion valve and detector).
Replace the guard column (see Chapter 3.18,
page 44).
Install the separation column in the oppo-
￭
site flow direction (if the leaflet says this is
permissible) and rinse into a beaker.
Replace the separation column (see "Con-
￭
necting the separation column", page 48).
Check the installation of the sample loop (see
"Optional: Exchanging the sample loop",
page 27).
Use the sample degasser .
Increase the rinsing time (see Chapter 5.13,
page 82).
Request Metrohm Service.
Seal the Vacuum connector tightly with a
￭
threaded stopper (6.1446.040).
6 Troubleshooting
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89