Verification of ORP electrodes

First look for broken sensor (platinum ring or tip). If the sensor seems to be OK, make sure your ORP sensor is well conditioned (soak sensor into HI 7091L or HI 7092L solution for 15 minutes). Also make sure the electrode is fully filled with proper electrolyte. If the sensor is still giving bad readings, see cleaning procedure and preparation & testing of ORP electrodes.

Cleaning & storage of ORP electrodes

ORP electrodes are cleaned with the same cleaning procedure used for pH electrodes. On ORP electrodes, this cleaning procedure will clean the electrode’s junction.

In addition to that, platinum or gold tips & rings can be clean as follow:

Platinum tip or ring: Soak the electrode into HI 7092L solution for 30 minutes.

Gold tip or ring: Soak the electrode into HI 7091L solution for 30 minutes.

It is recommended to make a quick test with HI 7021L or HI 7022L prior to use.

When not used, ORP electrodes should be stored into HI 70300L storage solution.

Preparation & testing of ORP electrodes

ORP electrodes need to be conditioned prior to use.

When the electrode is new, soak the tip in warm tap water. This will enhance the flow of the reference junction. To check function of the electrode, immerse the tip in ORP solution HI 7021L or HI 7022L. The reading should be +/- 50mV from the value indicated on the bottle.

If the reading is not within +/-50mV, oxidizing or reduction treatment with HI 7092L or HI 7091L is required. It will also prepare the electrode’s surface and speed initial response time. Since in-line process electrodes are already in a solution, a simple test with either HI 7021L or HI 7022L will show you the electrode’s condition.

Should your probe not be accurate enough after conditioning & testing, follow the cleaning procedure.

Gold tip vs Platinum tip

ORP sensor, platinum or gold ?

Platinum sensor: use in oxidizing reaction (above 500mV) such as pools & spas, municipal drinking water.

Gold sensor: use in reducing environment (below 500mV) such as galvanic applications, mining industry (Cyanide).