EOX determination
multi X 2500
78
10.
Connect the measuring gas hose from the sulfuric acid
container to the gas inlet tube (4) using the Teflon screw
connection.
NOTICE! The two conical nipples of the Teflon screw
connection must fit tightly to the hose. Otherwise, the gas-
tightness of the connection cannot be guaranteed.
11.
Connecting the electrodes at the inside of the rear panel of
the chlorine module:
Connection sensor electrode (1)
Connection silver electrode (2)
Connection platinum electrode (3)
7.1.2
Preparing the measuring cell
The preparation of the measuring cell for daily measurements includes the following
steps:
Preparation of the electrolyte solution
Execution of the end point routine
This section describes the preparation of the measuring cell "high sensitive". See
chapter "Preparing the measuring cell", p. 59 for information on how to prepare the
measuring cells "sensitive" and "high concentration".
Measurements with the measuring cell "high sensitive" require an electrolyte solution.
In addition to that, an internal electrolyte for the sensor electrode must be prepared
which is also used for storing the electrode.
WARNING
100 % acetic acid (glacial acetic acid) can cause severe chemical burns! Wear the
appropriate protective clothing when preparing the electrolyte solution! Observe all
instructions and specifications in the safety data sheet!
800 ml of acetic acid c = 100 % (glacial acetic acid)
2.7 g of sodium acetate p.a., anhydrous
8.52 g of sodium sulfate p.a., anhydrous, max. chlorine content 0.001 %
Proceed as follows to prepare 1 l of electrolyte solution for the measuring cell "high
sensitive":
1.
Dilute 2.7 g of sodium acetate (CH
3
COONa) in 200 ml of ultrapure water in a 1-
liter volumetric flask.
2.
Carefully add 800 ml of glacial acetic acid. Keep moving the flask while pouring the
acid. Carefully shake the mixture.
Preparation of the
electrolyte solution
Reagents required:
Preparation of the
electrolyte solution
