￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
6 Troubleshooting
884 Professional VA
￭￭￭￭￭￭￭￭
71
Problem
Cause
Remedy
￭
If necessary, replace the capillary or needle
(see the
Multi-Mode Electrode pro docu-
ment (8.110.8018XX)
).
The pH value of the meas-
uring solution is not cor-
rect.
Check the pH value and adjust it by adding a
buffer, acid or base if necessary.
A peak was not
found when measur-
ing the sample but
the standard addi-
tion is being evalu-
ated correctly.
The peak in the sample has
shifted.
Ensure that the peak actually originates from
the analyte. If it does, set the characteristic
potential and have the results recalculated. If it
does not, locate the cause based on "Double
peak present" and resolve the problem.
The concentration of the
ion to be determined is too
small.
￭
Use more sample.
￭
Use stripping voltammetry (HMDE) instead
of polarography (DME, SMDE) if the appli-
cation allows.
￭
Extend the deposition time (only HMDE).
The deposition time for
stripping voltammetry is
too short.
In the voltammetry command (DP, SQW),
increase the deposition time under
Potentio-
static pretreatment
.
A slight hissing
noise can be heard
at the measuring
head.
The measuring head is not
correctly locked in place on
the instrument. This can
allow nitrogen to escape
at the connection.
Remove the measuring head and put it back in
place until it clearly clicks in place.
The seals at the transitions
are too old.
Contact Metrohm Service for how to proceed.
Curves have a large
amount of noise (all
electrode types).
The needle is not adjusted.
￭
Adjust the needle (see the
Multi-Mode
Electrode pro document (8.110.8018XX)
).
￭
In the case of an SMDE, alternatively use a
DME if the application allows.
The capillary and/or needle
is defective.
Replace the capillary and needle. If necessary,
clean the MME pro (see the
Multi-Mode Elec-
trode pro document (8.110.8018XX)
)
The tapping mechanism on
the VA stand base is not
functioning correctly.
￭
Check the positioning of the capillary in the
MME pro. The capillary has to be centered
in the retaining screw.
Содержание 884 Professional VA
Страница 1: ...884 Professional VA Manual Short Instructions 8 884 8002EN 2017 06 30 ...
Страница 2: ......
Страница 8: ......
Страница 42: ...3 2 Equipping the MME measuring head 34 884 Professional VA Figure 18 Connecting the working electrode ...
