7.3 Application problems
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50
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Problem
Cause
Remedy
The method parameters
are not correct.
Check the voltammetric parameters, in particu-
lar the parameters for cyclovoltammetric and
potentiostatic pretreatment.
The electrode is not in a
good condition.
Clean the electrode as recommended in the
application documentation and repeat the
determination. If the situation does not
improve, replace the electrode by a new one.
The standard solution is
too old.
Prepare a fresh standard solution. Also con-
sider the age of the standard stock solution.
The stirrer does not work
correctly.
See
Stirrer - the stirrer does not rotate.
Temperature change of the
measuring solution.
The temperature of the measuring solution has
a direct influence on the measured current.
Therefore, a workplace close to an air condi-
tioner or with direct exposure to sunlight
should be avoided, since it can significantly
change the temperature in the measuring solu-
tion.
The curves are generally
not reproducible.
See
Curve shape - the curves are very noisy.
and
Curve shape - the curves show a jump, a
step or a flat line.
Calibration curve -
the standard addi-
tion is too small /
too big.
The concentration of the
standard addition solution
is not correct.
Check the standard solution used for the
determination. In case of doubts prepare a
fresh standard solution. Also check whether
the correct concentration for the standard
solution is specified in the method.
The addition volume is not
correct.
Verify the standard addition volume used in
the determination. In case of doubts repeat
the determination with the correct volume.
Also check whether the correct volume for the
standard addition is specified in the method.
The total volume of the
measuring solution is not
correct.
Verify the sample volume used in the determi-
nation. In case of doubts repeat the determi-
nation with the correct volume. Also check
whether the correct sample volume is specified
in the method.
Summary of Contents for 2.946.0010
Page 1: ...946 Portable VA Analyzer 2 946 00x0 Manual 8 946 8003EN ...
Page 2: ......
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Page 12: ...1 4 Symbols and conventions 4 Note This symbol marks additional information and tips ...
Page 79: ... 8 Technical specifications 71 8 8 Connection Connection USB version 1 1 or higher ...