Aztec 600 ISE ammonia and fluoride
Single-stream ion-selective analyzers
3 Installation
20
OI/AXM630–EN Rev. I
3.6.5 Ammonia Probe Preparation
The ammonia probe is supplied in kit form and must be
assembled before use. Referring to Fig. 3.12:
1. Unscrew end cap
A
from probe body
B
. Rinse the
probe body with distilled or de-ionized water and allow to
drain.
2. Remove the teat from glass pH electrode
C
. Rinse the
electrode with distilled or de-ionized water and dry with a
paper tissue.
3. Screw electrode
C
into probe body
B
until the top of
the electrode is flush with the top of the probe body.
4. Note the number on the electrode cap
D
that is aligned
with the mark on the body. Unscrew the electrode 4 full
turns using the number and mark as reference.
5. Insert membrane
E
into end cap
A
and place
membrane sealing washer
F
centrally on it.
6. Screw end cap
A
firmly onto body
B
; both body seal
G
and membrane sealing washer
F
must be under
compression but do not screw the end cap on so tightly
that membrane
E
distorts.
7. Hold the probe upright and inject the filling solution
provided through filling hole
H
. Fill the probe to a depth
of between 50 and 60 mm (1.96 and 2.36 in.), ensuring
that reference element
J
is immersed in the solution.
Wipe any excess filling solution from the body.
8. Tap the end of the probe with the finger to dislodge any air
bubbles trapped between the end of the electrode and the
membrane.
9. Screw electrode
C
down 4 turns until the number on
electrode cap
D
noted at step 4 is again aligned with the
mark on the body (the top of the electrode should be flush
with the top of the probe body).
10. Screw electrode
C
down a further 1.0 ±0.1 turns. Check
that the tip of the electrode is pressing against the
membrane. If the electrode response is sluggish, screw
the electrode down by a further 0.2 to 0.3 turns. DO NOT
overtighten – this will puncture the membrane.
11. Push probe cap
K
onto the top of probe body
B
ensuring it covers filling hole
H
.
Fig. 3.12 Ammonia Probe Assembly
Note.
A newly-assembled ammonia probe must be fitted to
the analyzer and exposed to sample for 2 to 4 hours before
a calibration is attempted.
Note.
For measurements of very strong ammonia solutions,
the molarity of the ammonium chloride in the filling solution
(normally 0.1M Ammonium Chloride) should ideally be
adjusted such that it is 2 – 3 times greater than the molarity
of the strongest Ammonia solution to be measured.
If the probe is to be used continually near its upper limit
(>200 ppm), it may be preferable to add 0.2 g ammonium
chloride to the 50 ml filling solution bottle, to prolong the
interval required between filling solution replenishment.
A
B
C
E
F
G
H
J
K
D
