341350A-en-US_V1.3 8/15
7
pH
Troubleshooting
Chart
Symptom
Cause
Recommended
Solution
Long
response
time
or
reading
drift
Clogged
Junction
Soak
in
4.07
M
KCL
@
60
o
C
for
30
minutes
Oil,
paint,
dyes,
suspended
solids
on
sensor
Rinse
electrode
alternately
with
materials
solvent
then
buffer
7.00
Dry
Bulb
Long
term
storage
without
wetting
Soak
electrode
tip
in
wetting
cap
filled
with
1ml
7.00
buffer
for
24
to
48
hours
Static
Charge
Wiping
electrodes
Rinse
electrode
in
7.0
buffer
and
blot.
Do
no
wipe
electrode.
Same
readings
in
different
buffers
and
samples
Cracked
or
broken
bulb
Replace
electrode.
Use
bulb
guard.
Avoid
plunging
electrode
to
bottom
of
container
and
spinning
bars.
A
wetting
cap
will
protect
bulb
between
measurements.
Erratic
LCD
display
Samples
have
low
ionic
strength
(lacks
salt);
e.g.
distilled,
de
‐
ionized,
boiled,
lake
water
(high
pressure)
For
each
50
ml
of
sample
add
1
drop
(50uL)
of
SAT.KCL
No
alteration
in
pH
will
occur
by
inert
KCL.
Notes
on
pH
measurements
and
electrodes
1.
The
Electrode
should
be
stored
in
its
wetting
cap
until
used.
Use
a
pH
4
buffer
solution
or
a
4.0
M
KCL
solution.
2.
If
bubbles
are
seen
in
the
bulb
area,
hold
the
electrode
by
its
cap
and
shake
downwards
until
bubbles
are
removed.
3.
To
improve
speed
of
response,
vigorously
stir
the
electrode
in
the
sample,
buffer,
or
rinse
solution.
4.
After
exposure
to
a
sample,
buffer,
or
rinse
solution,
shake
the
electrode
with
a
snap
motion
to
remove
residual
drops
of
solution.
5.
When
possible,
use
part
of
the
next
sample/buffer
to
be
measured
as
a
rinse
solution,.
6.
Keep
buffers
and
samples
at
the
same
temperature
to
avoid
temperature
effects.
7.
pH
readings
stabilize
faster
in
some
solutions
than
others;
allow
time
to
stabilize.
8.
Electrodes
deteriorate
over
time.
If
accuracy
falls
to
10%
the
electrode
should
be
cleaned.
If
no
improvement
is
observed,
replace
the
electrode.
Notes
on
the
Conductivity/TDS/Salt
Cell
1.
Cell
Storage:
On
sheathed
cells,
replace
the
sheath
over
the
cell
when
storing.
For
non
‐
sheathed
versions,
soak
the
cell
tip
in
de
‐
ionized
water
for
storage.
2.
Cell
Cleaning:
After
each
use,
the
cell
tip
should
be
rinsed
with
de
‐
ionized
water.
If
solids
build
up
inside
the
cell
carefully
remove
with
a
cotton
swab
soaked
in
solvent
taking
care
not
to
touch
the
metal
parts
of
the
inner
cell.
www.
GlobalScientificSupply
.com
GLOBAL SCIENTIFIC SUPPLY
The Laboratory Supply Company!
