Metrohm 781 pH/Ion Meter - Manual (Page 11)

1 Introduction
780/781 pH/Ion Meter, Manual
1
1 Introduction
This Manual provides you with a comprehensive overview of the instal-
lation, working principles and operation of the 780 pH Meter and 781
pH/Ion Meter. As these two instruments are identical as far as the three
measuring modes of the 780 pH Meter are concerned (pH, temperature
and potential) and their operation in these modes is also identical, the
Manuals for both have been incorporated in a single document. The
special measuring mode of the 781 pH/Ion Meter – the measurement of
concentration – is, like the other measuring modes, described in sepa-
rate sections. These sections, which apply only to the operation of the
781 pH/Ion Meter, are marked accordingly.
Information about the use of Metrohm pH or ion-selective electrodes
can be found in the appropriate leaflet and the ISE Manual that is in-
cluded with the electrode.
Additional theoretical principles can be found in the Metrohm Mono-
graph "Electrodes in Potentiometry".
You can also request our descriptions of applications involving pH and
ISE measurements in the form of Application Notes and Application
Bulletins from your local Metrohm agency or download them from the
Internet under www.metrohm.com.
Fig. 1: 781 pH/Ion Meter connected to 801Magnetic Stirrer
1.1 Instrument description
Both instrument versions, the 781 pH/Ion Meter and the 780 pH Meter,
are used for measuring pH, temperature and potential reliably and at
high resolution. The 781 pH/Ion Meter differs from the 780 pH Meter by
having an additional operating mode for the potentiometric determina-
tion of the concentration by using ion-selective electrodes (Conc
mode).
Both instruments have comprehensive monitoring functions (for calibra-
tion, validation and service intervals), diagnostic functions and an au-