1 INTRODUCTION
The Ammonia Probe, Model 8002, is a high
sensitivity gas sensing probe developed by
ABB. It measures the partial pressure, and
hence concentration of ammonia in aqueous
solution. Ammonium concentrations can be
measured after the sample has been treated
with alkaline buffer to generate ammonia. The
probe has a Nernstian response up to 1000mg
–1
NH
l
or 10,000mg NH
3
the internal filling solution. The lower limit has not
been determined as it is set by the purity of
available water.
Model 8002 should be used in conjunction with
an expanded scale pH meter such as Model
7046; for convenience the direct reading
concentration scales may be used with the
function switches set to monovalent anion. The
probe is supplied with membranes and filling
solution and a flow-through cap which enables
continuous analyses of up to 60 samples per
hour, when incorporated into a suitable flow
system.
2
–1
l
with modification of
3
Fig. 1.1 Contents of Kit
The probe may also be used as a sensor in
industrial monitors, for example the Model 8232
Ammonia Monitor, an industrial continuous flow
analyser
incorporating
standardisation.
Model 8002 is widely used for the determination
of ammonia in boiler water, river water, treated
and untreated sewage, etc., (see References 2,
3, 5, 6, 7, 9 and 10). Total nitrogen in the forms of
ammonia in the residue from the Kjeldahl
digestion may also be measured quickly and
easily with the probe without the need for the
usual final distillation step, (see References 4
and 8). The internal filling solution of the probe
must be modified in this application and in the
measurement of other samples containing a
high concentration of dissolved species.
automatic