tip of the DO meter completely submerged. If a terminal end has black dirt on it
and does not become whitish, leave undisturbed for additional time.
6. Wash away the ammonium solution in pure water. If it does not wash well, dip it
into pure water for a while.
7. Remove shavings by washing well with pure water, and then rinse it out three
times in a potassium chloride solution (KCl).
8. Fill the tip with KCl and attach a membrane. Confirm that the film is not wrinkled
and that air bubbles are not present inside of the membrane. When air bubbles are
present, reattach the membrane. Remove it by pulling the edge of the membrane
with an O-ring when a wrinkle is observed. Cut away any extra membrane
afterward.
9. Place the glass cover and a stirring rotor bar into the cap, and attach it to the tip of
the electrode. Prevent the silver electrode from touching the cap.
When using electrodes that require water flow to measure the DO (e.g., polarographic oxygen electrodes), use a perforated cap with a stirring rotor bar in the sensor
region, and stir only near the sensor to measure DO. A stirring rotor bar can be
moved smoothly by placing a circular glass cover at the bottom of the perforated cap
and placing the rotor on it. A method of attaching this stirring system to the
YSI-5750 is shown in Fig. 4.2. Insert the electrode (within which the stirring system
has been emplaced) until it is in contact with the bottom of the 300 mL Erlenmeyer
flask, and affix it using a rubber or silicon gasket or clip. Do not block the mouth of
the flask. Attach an insulating material and blank paper to the stirrer so that the heat
of the stirrer will not reach the flask. A white acrylic board (which has been
processed to a thickness of 5 mm and has a gap of 5 mm formed below it) may be
substituted for the insulating material and blank paper. Carry the flask equipped with
an electrode on this board, stir it, and then measure the DO.
4.2.2 Fluorometric DO Meter
Because light leaks out from the side of the electrode, a fluorescence-type DO meter,
such as the ProODO (YSI, Japan), is used to interrupt light in a black rubber tube
(Fig. 4.3). Affix this electrode using a rubber or silicon gasket or a clip from the
Fig. 4.2 Setup of DO electrode
4 Preparation of the Microcosm N-System
33
and does not become whitish, leave undisturbed for additional time.
6. Wash away the ammonium solution in pure water. If it does not wash well, dip it
into pure water for a while.
7. Remove shavings by washing well with pure water, and then rinse it out three
times in a potassium chloride solution (KCl).
8. Fill the tip with KCl and attach a membrane. Confirm that the film is not wrinkled
and that air bubbles are not present inside of the membrane. When air bubbles are
present, reattach the membrane. Remove it by pulling the edge of the membrane
with an O-ring when a wrinkle is observed. Cut away any extra membrane
afterward.
9. Place the glass cover and a stirring rotor bar into the cap, and attach it to the tip of
the electrode. Prevent the silver electrode from touching the cap.
When using electrodes that require water flow to measure the DO (e.g., polarographic oxygen electrodes), use a perforated cap with a stirring rotor bar in the sensor
region, and stir only near the sensor to measure DO. A stirring rotor bar can be
moved smoothly by placing a circular glass cover at the bottom of the perforated cap
and placing the rotor on it. A method of attaching this stirring system to the
YSI-5750 is shown in Fig. 4.2. Insert the electrode (within which the stirring system
has been emplaced) until it is in contact with the bottom of the 300 mL Erlenmeyer
flask, and affix it using a rubber or silicon gasket or clip. Do not block the mouth of
the flask. Attach an insulating material and blank paper to the stirrer so that the heat
of the stirrer will not reach the flask. A white acrylic board (which has been
processed to a thickness of 5 mm and has a gap of 5 mm formed below it) may be
substituted for the insulating material and blank paper. Carry the flask equipped with
an electrode on this board, stir it, and then measure the DO.
4.2.2 Fluorometric DO Meter
Because light leaks out from the side of the electrode, a fluorescence-type DO meter,
such as the ProODO (YSI, Japan), is used to interrupt light in a black rubber tube
(Fig. 4.3). Affix this electrode using a rubber or silicon gasket or a clip from the
Fig. 4.2 Setup of DO electrode
4 Preparation of the Microcosm N-System
33