EN-27
Thermo Scientific Orion Star
™
and Star Plus Meter User Guide
i . A manual calibration involves performing a Winkler titration and using
that sample as a calibration standard . The oxygen level result from the
titration is entered in a manual calibration as the dissolved oxygen value .
This correlates the meter input to the Winkler titration . This method is
inherently less accurate, due to the possibility of titration errors .
d .
– A zero point calibration is performed in an oxygen-free solution .
A zero point calibration is not generally required unless measurements will
be taken below 10% saturation or 1 mg/L . Zero the probe when using a new
membrane, using fresh filling solution or when measuring dissolved oxygen
levels below 1 mg/L . An air calibration should be performed prior to the zero
point calibration .
2 . Allow the probe and calibration standard (water saturated air, air saturated water,
Winkler standard or oxygen-free solution) to reach equilibrium .
3 . In the measurement mode, press
until the arrow icon points to the bottom
line, press
until the
% sat
or
mg/L
icon is shown and press
to begin
the calibration .
4 . Wait for the dissolved oxygen reading to stabilize .
a . If an air calibration is performed, the meter will display 102 .3%
and automatically return to the measurement mode .
b . If a water calibration is performed, the meter will display 100 .0%
and automatically return to the measurement mode .
c . If a manual calibration is performed, wait for the
mg/L
icon to stop flashing
and enter the dissolved oxygen value by pressing
until the first digit to
be changed is flashing, press
/
to change the value of the flashing
digit and continue to change the digits until the meter displays the correct
dissolved oxygen value . Once the dissolved oxygen value is set, press
until the decimal point is in the correct location .
d . If a zero point calibration is performed, the meter will display 0 .00 and
automatically return to the measurement mode .
Polarographic Dissolved Oxygen Technique
Summary of Contents for Orion Star
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