Chapter 16 Reference
16.2 Measuring mV (oxidation-reduction potential [ORP])
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If the prepared ORP standard solution is allowed to stand in open air for one hour or more, it
may undergo transformation. For this reasons ORP standard solution that has finished being
prepared cannot be stored.
When measuring a solution that has low concentrations of oxidants and reductants after con-
ducting an operational check using a standard substance, the measured values may not sta-
bilize or the results of measurement might not be repeatable. If this is the case, use the meter
after immersing the electrodes in the solution again and mixing it thoroughly.
● Precautions when measuring actual samples
●
Note that when measuring the ORP of solution that has extremely low
concentrations of oxidants and reductants, such as tap water, well water, or
water treated with purifying equipment, there may be less responsiveness,
repeatability, and stability, in general.
●
When alkaline water is allowed to stand, its ORP undergoes big changes. Always
measure alkaline ion water promptly.
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