BT57i ORP sensor User’s Guide
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As a result, you do not have to perform a new calibration, just use the calibration
supplied by the sensor memory (EEPROM) or the calibration stored in the Coach
Sensor Library.
If you are doing water quality testing or performing a chemistry experiment that
requires a very accurate calibration, you will need to obtain two commercial ORP
standards. Using these standards, perform the following 2-‐point calibration:
•
For the first calibration point, rinse the tip of the electrode with distilled water,
and place the electrode into the first standard. When the voltage reading
displayed by the data-‐collection program stabilizes, enter the ORP value (mV) of
the first ORP standard.
•
For the second calibration point, remove the electrode from the first standard,
rinse it with distilled water, and place it into the second standard. When the
displayed voltage reading stabilizes, enter the ORP value (mV) of the second
standard.
•
Rinse the electrode with distilled water and place it into the sample to be
measured. You are now ready to take measurements with the calibrated ORP
sensor.
Suggested experiments
Redox reactions control the behavior of many chemical constituents in drinking
water, wastewater and aquatic environments. The reactivity and solubility of critical
elements in living systems are strongly dependent on redox conditions. ORP values
are used much like pH values to determine water quality. For example for swimming
pools at a normal pH value between 7.2 and 7.6, the ORP value must be kept above
700 mV to kill unwanted organisms. In contrast, in order to support life, natural
waters need a much lower ORP value. Generally ORP values above 400 mV are
harmful to aquatic life.
The ORP sensor can also be used for redox titrations to determine the equivalence
point in an oxidation-‐reduction reaction.
