General Information On Measurement; Notes On Ph Measurement - ProMinent Portamess 911 pH Instruction Manual

4 General Information on Measurement

Note The chapter "General Information on Measurement" pro-
vides a summary of the most important points to be ob-
served during pH measurement. You can skip this chapter
if you are sufficiently familiar with the practice of pH mea-
surement.

Notes on pH Measurement

General
Two electrodes, a glass electrode and a reference elec-
information
trode, are required for electrometric pH measurement.
They are usually offered combined in a glass or plastic
body as a so-called combination electrode.
During pH measurement, simultaneous temperature detec-
tion is required. For a correct pH value, you must always
specify the respective measurement temperature, e.g.
pH = 7.15.
25°C
Using a temperature probe together with the electrode
allows to optimally use the advantages of the microproces-
sor controlled pH meter.
Combination electrodes with integrated temperature probe,
e.g. PHEKT–013–F combination electrode (order no.
1007774), are particularly advantageous.
The measuring characteristics of pH electrodes are differ-
Calibration
ent for each electrode, are variable and temperature-de-
and measure-
pendent. Therefore, the meter must be adjusted to the
ment
respective current electrode characteristics. This process
is called calibration.
For calibration, you take measurements of buffer solutions.
These are solutions with exactly defined pH values. With

the Portamess 911 pH two calibration modes are avail-
able, i.e. automatic calibration using Calimatic
al calibration.

and manu-
Information on Measurement 27