User Manual

Optical pH Sensors | User Manual

For the first calibration point, prepare a pH 2 buffer solution based using the

PyroScience buffer capsules (item no. PHCAL2) or a custom calibration buffer.

It is recommended to perform the calibration at the same temperature of the actual pH

measurements.

It is strongly recommended to perform calibration at conditions close to the

environmental conditions during measurements. Ensure constant conditions during

calibration.

IMPORTANT: If the sensor was previously stored under dry conditions, let the

sensor equilibrate for at least 60 min in the buffer to achieve wetting of the

sensor membrane. This step is necessary to achieve high accuracy. For the best

result, let the sensor soak in water overnight. The equilibration can be reduced

to 5 minutes for the pH Minisensor.

After completing the Settings Wizard for all channels, open the Calibration Wizard by

clicking the "Cal." button in the respective row ("Ch. 1" to "Ch. 4") of the table in the main

window. The software will guide you through the complete calibration procedure.

Insert the pH and temperature sensor into the stirred buffer, and ensure that the sensor

tips are completely immersed into the water and free of air bubbles. Let the sensor

equilibrate and perform the calibration. Wait for a stable sensor signal as this is

substantial for correct pH measurements (this can take several minutes depending on

the temperature and stirring rate). For best result, wait at least for 15 minutes.

With increasing stability of the sensor signal the color will change from red to orange to

yellow to green. Although a calibration is possible in the orange state, we strongly

recommend to wait until Take Value and the frame of the graph have turned to green.

After setting the first calibration point, wash the sensor with distilled water and

submerse the sensor in the next calibration buffer without letting the sensor dry.

IMPORTANT: The sensor membrane should not dry out between calibration and

your measurement.