Thermo Fisher Scientific CyberScan DO 5000 - Manual (Page 71)

Instruction Manual CyberScan DO5000
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6.1 DO Standardization
The CyberScan DO 5000 has two standardization modes. There is
auto- standardization, merely requiring the touch of a button to
complete. There is also manual standardization. Here the DO value,
in either % Saturation or mg/L units, of the standard will be entered
manually by means of a keypad, which appears on the screen.
It is necessary to standardize the meter when the probe is in an
environment with a known concentration of oxygen. One such
environment is water-saturated air. Most commonly, this involves
placing the DO probe into a BOD bottle filled with about 1 inch of
water. Stirring is not required. Another environment is air-saturated
water, achieved by aerating 300 – 500 ml of water for at least 15
minutes. The probe can be placed into the water with stirring
provided. Lastly, the probe is placed into an environment whose
oxygen content has been determined by a Winkler titration. The
meter is standardized in the manual mode.
Prior to standardization, adequately prepare the probe as
recommended in its operation manual.
ONCE STANDARDIZATION IS SET, IT WILL BE APPLICABLE IN
OTHER MODES.