Metrohm 889 IC Sample Center - Manual (Page 51)

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6 Troubleshooting
889 IC Sample Center
￭￭￭￭￭￭￭￭ 43
6.2 Analytical problems
Analytical problems such as poor reproducibility and carry-over can occur
in any chromatography system. The cause is usually difficult to find. First
of all, you should attempt to determine whether the problem is caused by
the Autosampler or another component of the system.
Please take into consideration the fact that analytical problems can also be
caused by external influences such as temperature or light-sensitive sam-
ple. Make sure that the application was able to be performed previously
without problems and that no changes have been made to the system.
Some causes and possible solutions for analytical problems are listed
below. Contact your service point for additional help.
6.2.1 Autosampler
Problem Cause Remedy
The reproducibility
does not correspond
to the specifications. There is air in the flow
path. Carry out a standard washing procedure (in
MagIC Net
™ under Manual control).
The syringe is leaking. ￭ If the leakage occurs on the upper end of
the syringe, check the correct assembly of
the syringe.
￭ If the leakage occurs on the lower end of
the syringe, replace the piston tip or the
entire syringe.
The syringe valve is leaking. Check the valve or replace it.
The rotor seal is worn out. Replace the seal and check the stator.
There is a dead volume in
the tubing connections. Reinstall the connections with new pressure
screws.
There is air in the syringe. Rinse the syringe (see Chapter 3.6, page 18).
A peak which is too
high occurs with a
blank. The sample properties and
the hardware do not corre-
spond. Check the hardware:
￭ Needle — Carry out the standard washing
procedure (in order to rinse the needle on
the in- and the outside).
￭ Valve — Replace rotor by another type.
￭ Capillary connections — Replace capillary
between Autosampler and column or use
another washing solution.