Metrohm 940 Professional IC Vario ONE/Proep 2 - Manual (Page 90)

6.1
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940 Professional IC Vario ONE/Prep 2 (2.940.1120)
Problem Cause Remedy
The background
conductivity is too
high. The incorrect eluent is
being used. Change the eluent (see Chapter 5.5.2, page
56).
The retention times
are poorly reprodu-
cible. The eluent path has a leak. Check all of the connections along the eluent
path and fix the leak.
The eluent path is blocked. Check the eluent path and fix the blockage.
The eluent contains gas
bubbles. ￭ Inspect the connectors for the eluent
degasser .
￭ Deaerate the high-pressure pump (see
Chapter 3.19, page 41).
Chromatograms
have poor resolution Separation column –
Diminished separating effi-
ciency. ￭ Regenerate the separation column (see
Chapter 5.15.4, page 78).
￭ Replace the separation column (see "Con-
necting the separation column", page 47).
Extreme spread of
the peaks in the
chromatogram.
Splitting (dual
peaks) Capillary connections –
dead volume in the system. 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).
Guard column – Dimin-
ished efficiency. ￭ Replace the guard column (see Chapter
3.20, page 43).
Separation column – Dead
volume at the column
head. ￭ Install the separation column in the oppo-
site flow direction (if permitted by the leaf-
let) and rinse into a beaker.
￭ Replace the separation column (see "Con-
necting the separation column", page 47).
Precision problems -
the measured values
are highly scattered. Injection valve – Sample
loop. Inspect the installation of the sample loop (see
"Optional: Exchanging the sample loop",
page 28).
Sample – There are gas
bubbles in the sample. Use the sample degasser .
Sample – The rinsing vol-
ume is too small. Increase the rinsing time (see Chapter 5.13,
page 74).
Injection valve – Defective. Request Metrohm Service.