Metrohm 850 Professional IC Cation - LP-Gradient - Manual (Page 91)

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6 Troubleshooting
850 Professional IC Cation – LP Gradient
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Problem Cause Remedy
Extreme spread of
the peaks in the
chromatogram.
Splitting (dual
peaks) Connections – dead vol-
ume in the system. Check connections (see Chapter 3.5, page 17)
(use PEEK capillaries with an internal diameter
of 0.25 mm between the injection valve and
detector).
Guard column – diminished
performance. ￭ Replace guard column (see Chapter 3.18,
page 52).
Separation column – dead
volume at column head. ￭ Install separation column in reverse flow
direction (if permitted by the information
sheet).
￭ Replace separation column (see "Connect-
ing and rinsing the separation column",
page 54).
Precision problems -
significant scatter-
ing of the measured
values Sample – Gas bubbles in
the sample. Use sample degasser (see Chapter 3.14, page
44).
Injection valve – sample
loop. Check installation of the sample loop (see
Chapter 3.15.1, page 46).
Sample – Rinsing volume
too low. Prolong the rinsing time (see Chapter 5.8,
page 74).
Injection valve – defective. Request Metrohm Service.
Unexpected change
to the retention
times in the chroma-
tograms Separation column –
diminished separating effi-
ciency. ￭ Regenerate separation column (see Chap-
ter 5.11.4, page 77).
￭ Replace separation column (see "Connect-
ing and rinsing the separation column",
page 54).
Eluent – Gas bubbles in the
eluent. Check connections of the eluent degasser (see
Chapter 3.9, page 32).
High pressure pump –
defective. Request Metrohm Service.
Vacuum is not being
built Eluent Degasser – Connec-
tor Vacuum on the rear of
the instrument not (tightly)
sealed. ￭ Seal the connector Vacuum tightly with a
6.144.6040 threaded stopper.
or when using an 872 Extension Module:
￭ Connect an FEP tubing between the IC
instrument and the Extension Module and
tighten both clamping screws until they
seal.