Metrohm 2.946.0010, Руководство пользователя

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7.3 Application problems
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Problem Cause Remedy
The concentration of ana-
lyte is too high, the elec-
trode is overloaded. Reduce the sample volume or use a more
diluted sample. Also consider the linear work-
ing range of the method
(see chapter 7.4.1,
page 60) .
Interference which leads to
complex formation. Identify the interference and remove it from
the measuring solution.
The electrolyte is too old. Prepare a fresh electrolyte solution. Also con-
sider the stability and age of the reagents used
for the preparation.
Peak shape - the
peak is cut The current measuring
range is too low. Select the next higher current measuring range
or consider using current measuring range
Auto .
Peak shape - the
peak looks strange.
Concentration in the mea-
suring solution is too high. Reduce the sample volume or use a more
diluted sample. Also consider the linear work-
ing range of the method
(see chapter 7.4.1,
page 60) .
Interference from the sam-
ple matrix. Run a determination in standard solution to
verify that the application works properly.
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If the peak shape in standard solution is
not ok, clean the electrode as recommen-
ded in the respective application documen-
tation. If that does not improve the situa-
tion, replace the electrode by a new one.
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If the peak shape in standard solution is ok,
identify the interference in the sample and
remove it from the measuring solution.
The method parameters
are not correct. Check the voltammetric parameters, and adapt
them if necessary.
Result - the result is
higher than
expected Blank or contamination
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Run a blank determination to determine
the reagent blank. In case of blank prob-
lems check whether reagents with a better
purity are available or reagents from a dif-
ferent source show lower blanks.
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Be aware of contamination risks. Every sur-
face, measuring vessel, electrode and other
equipment in contact with sample or
reagents can be contaminated.