Rdo Optical Dissolved Oxygen Calibration - Thermo Scientific Orion Star Manual Del Usario

RDO Optical Dissolved Oxygen Calibration

1 . Select one of the following calibration modes in the setup menu .
a . – An air calibration is performed in water saturated air using
the calibration sleeve . This is the simplest and most accurate method .
i . The highest possible accuracy is reached when calibration temperature
is the same as the measuring temperature .
ii . Moisten the sponge in the calibration sleeve with distilled water .
Insert the RDO probe into the sleeve without touching the water
saturated sponge .
b . – A water calibration is performed using water that is 100% saturated
with air . Bubble air into a water sample and gently stir the sample to prevent
the buildup of air bubbles on the optical cap .
c . – A manual calibration is performed using a water sample with
a known concentration of dissolved oxygen . This method can be used
to calibrate the RDO probe to the value achieved by a Winkler titration .
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 .
2 . Allow the RDO probe and calibration standard (water saturated air, air saturated
water, Winkler standard or oxygen-free solution) to reach equilibrium .
Thermo Scientific Orion Star and Star Plus Meter User Guide
™
RDO Optical Dissolved Oxygen Technique
®
EN-35