Metrohm 940 Professional IC Vario TWO/SeS/PP - Manual (Page 104)

6.1
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96 ￭￭￭￭￭￭￭￭
940 Professional IC Vario TWO/SeS (2.940.2400)
Problem Cause Remedy
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 49).
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 53).
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 5.15,
page 89).
Injection valve – Defective. Request Metrohm Service.
MCS – The vacuum is too
low. ￭ Check the connectors. If they are OK:
￭ Contact Metrohm Service.
Vacuum is not being
built Eluent degasser – Vacuum
connection on the rear of
the instrument is not
(tightly) sealed.