Metrohm 2.946.0010, Руководство пользователя

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5.2 Carrying out the determination of As(total) according to Application Bulletin 416
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38
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NOTICE
When the concentration in the sample is too high, less sample can be
used for the determination. The remaining volume to the original 15 mL
should be replaced by ultrapure water. Take care that the total volume
at the beginning of the determination is minimum 16 mL and at the
end of the determination not more than 23 mL. This restriction is due
to the construction of the scTRACE Gold electrode.
NOTICE
When not in use, the electrode should be stored dry. Before the sensor
is stored, it should be thoroughly rinsed with ultrapure water. To put it
back into operation, it is often sufficient to run a blank determination,
replacing the sample by ultrapure water but using the parameters for a
sample determination. If that is not sufficient, carry out the cleaning
procedure described in
Chapter 5.2.4 Cleaning of the scTRACE Gold
electrode (page 38) .
NOTICE
The scTRACE Gold electrode has a limited lifetime. If the performance
of the electrode cannot be recovered by the cleaning procedure descri-
bed in
Chapter 5.2.4 Cleaning of the scTRACE Gold electrode (page
38) , the electrode needs to be replaced. Indications for an outdated
electrode are:
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Significantly lower sensitivity.
￭
Higher or very noisy background current.
￭
Unusual peak shape.
5.2.4 Cleaning of the scTRACE Gold electrode
Mechanical cleaning of the scTRACE Gold electrode is not possible. If the
background current is unusually high or peaks show an unusual shape, an
electrochemical cleaning can be carried out. The cleaning procedure can
be carried out before, after, but also in between a series of determina-
tions.