CHLORIDE
HI 4007
7
HI 410
CHLORIDE
COMBINATION
Instruction Manual
HI 4007HI 4007
HI 4007
HI 4007HI 4007
HI 4107HI 4107
HI 4107
HI 4107HI 4107
Chloride Ion
Selective Electrode
Half-cell
Combination
1
HI 4007 Chloride Half-cellHI 4007 Chloride Half-cell
HI 4007 Chloride Half-cell
HI 4007 Chloride Half-cellHI 4007 Chloride Half-cell
HI 4107 Chloride Combination ElectrodeHI 4107 Chloride Combination Electrode
HI 4107 Chloride Combination Electrode
HI 4107 Chloride Combination ElectrodeHI 4107 Chloride Combination Electrode
I. I.
Introduction:Introduction:
I.
Introduction:
I. I.
Introduction:Introduction:
The Hanna HI 4007and HI 4107 are ion selective electrodes designed for the measurement of chloride ions in
aqueous solutions. The HI 4007 is a solid state half-cell
sensor that requires a separate reference. The HI 4107 is a
combination ion selective electrode.
IIII
SpecificationsSpecifications
II.
Specifications
IIII
SpecificationsSpecifications
Type: Solid State electrode with
a Silver Chloride pellet.
Ion(s) measured: Chloride (Cl-)
Measurement range: 1.0 M to 5 X 10
-5
M
35,500 to 1.8 ppm
Interfering ions: Cyanide, and Mercury ions
must be absent. Ratio of interfering ion to Cl- must be less
than the ratio indicated below:
for CO
-
2-
3
2-
3
iodide
carbonate
thiosulfate
1.0 for l
3.5 for Br-bromide
1.0 for OH-hydroxide
0.01 for S2O
Operating Temperature: 0-80°C
Operating pH: 2-11 pH
Dimensions: 12 mm (OD) X 120 mm
nominal insertion
(0.47” X 4.72”)
Connection: BNC
2
III. III.
Theory of OperationTheory of Operation
III.
Theory of Operation
III. III.
Theory of OperationTheory of Operation
::
:
::
The HI 4007 or HI 4107 chloride electrodes are potentiometric devices used for the rapid determination of free chloride ions in ground water, boiler water and drinking water.
The electrode functions as a sensor or ionic conductor. The
HI 4007 requires a separate reference electrode to complete
its electrolytic circuit. The HI 4107 has a reference electrode
incorporated in its design. The silver chloride pellet is practically insoluble in the test solutions being measured and
produces a potential change due to changes in the sample’s
ion activity. When the ionic strength of the sample is fixed
by the addition of ISA, the voltage is proportional to the
concentration of chloride ions in solution and the electrode
follows the Nernst equation.
E= E
+ 2.3 RT/nF log A
a
ion
E= observed potential
Ea= Reference and fixed internal voltages
R= gas constant (8.314 J/K Mol)
n= Charge on ion (-1)
A i=ion activity in sample
T= absolute temperature in K
F= Faraday constant (9.648 x 10
3
4
C/equivalent)
IV. IV.
Design elements of the HI 4007 and HI 4107Design elements of the HI 4007 and HI 4107
IV.
Design elements of the HI 4007 and HI 4107
IV. IV.
Design elements of the HI 4007 and HI 4107Design elements of the HI 4007 and HI 4107
electrodeselectrodes
electrodes
electrodeselectrodes
Cap
HI 4007
RIDE
CHLO
Sensor
Handle
Sensing
Membrane
Upper Cap
Upper
Threads
O-Ring
Ceramic Junction
on Inner Stem
Liquid junction
Spring
Fill Hole
O-Ring and
Plug
Outer Sleeve
Sensing
Membrane
4
V. Equipment required:V. Equipment required:
V. Equipment required:
V. Equipment required:V. Equipment required:
• Hanna HI 5315 Double Junction Reference Electrode
with HI 7072 Fill Solution for HI 4007.
• Hanna HI 4222 pH/ISE/mV meter or other suitable
ion or pH/mV meter. (Note: log/linear graph paper is
useful if an ISE (ion) meter is not available.
• Hanna HI 180 Magnetic Stirrer or equivalent with
Teflon coated stirring bars (HI 731320). (Note: isolate beakers from stirrer motor heat by placing insulating material such as foam or cork between them).
• Hanna HI 76404 Electrode Holder or equivalent.
• Plastic beakers (HI 740036P) or other suitable mea-
surement vessel.
VI. VI.
Solutions RequiredSolutions Required
VI.
Solutions Required
VI. VI.
Solutions RequiredSolutions Required
for Chloride Measurementsfor Chloride Measurements
for Chloride Measurements
for Chloride Measurementsfor Chloride Measurements
Select appropriate Hanna Instruments standard and ISA
from the list below:
0.1 M Sodium Chloride Standard, 500mL HI 4007-01
100 ppm Chloride standard, 500 mL HI 4007-02
1000 ppm Chloride standard, 500 mL HI 4007-03
ISA, 500 mL HI 4000-00
Using volumetric pipettes and glassware make dilutions to
bracket the concentration of the samples. Standards with
concentrations < 10
-3
M (35.5 ppm) should be prepared
daily.
Two mL of Hanna ISA for Halide electrodes (HI 4000-00)
should be added to 100 mL of sample or standard.
A user prepared acetate pH buffer may also be used to
adjust samples to approximately 4 pH. Add 10 mL per 100
mL sample or standard. Prepare 250 mL by dissolving
19.5 g ammonium acetate and 15.0 mL glacial acetic
acid in 200 mL deionized water and diluting to volume.
5
A user supplied oxidizing reagent may be used to supress
interferences such as hydroxide, sulfide, bromide, ammonia or cyanide . Add 10 mL to 100 mL standard or sample.
Permit sample to mix 10 minutes before measurements are
taken. Discard samples and
standards promptly as the
chloride in these will oxidize upon standing making them
unrelible. Do not permit electrodes to remain in this solution for long periods of time. Work in a hood and protect
eyes and skin. Prepare oxidizing reagent by diluting 6.25
mL analytical grade concentrated nitic acid into approximately 800 mL deionized water. Mix carefully. Dilute to 1
liter.
VIIVII
General GuidelinesGeneral Guidelines
VII.
General Guidelines
VIIVII
General GuidelinesGeneral Guidelines
• Calibration standards and sample solutions should
have the same ionic strength. ISA, acetate buffer or
oxidizing reagent should be added to both samples
and standards in the same ratio.
• Calibration standards and sample solutions should
be at same temperature.
• Thermally insulate beaker with standard or sample
from magnetic stirrer.
• Calibration standards and sample solutions should
be stirred at the same rate using identical sized TFE
coated stir bars.
• Rinse electrode pair with distilled or deionized water
between samples and gently dry off using soft disposable absorbent toweling. Do not rub sensor surface.
• Presoaking chloride sensor in a dilute standard will
optimize response. Do not use concentration above
10-3M.
• A scratched, pitted, or tarnished pellet surface can
cause drift, a loss of low level response, or poor repeatability. Optimum response can be restored by removing the damaged surface with the microabrasive strip
HI 4000-70.
6
• Avoid large changes in temperature (thermal shock)
as it may damage the sensor.
HI 4007
• Remove protective cover from sensor tip.
• Prepare HI 5315 reference electrode by filling electro-
lyte reservoir with HI 7072 fill solution.
• Place sensor and reference electrodes into electrode
holder and connect cable connectors to meter.
HI 4107
• Remove the protective plastic wrap that covers the
ceramic junction before assembling sensor for the first
time.
• HI 7072 reference fill solution should be added daily
to electrolyte reservior before electrode use.
• During measurement always operate electrode with
the fill hole open.
• During normal use, fill solution will slowly drain out
of the tapered cone junction at the lower portion of the
electrode. Excessive loss (>4 cm drop within 24 hours)
is not normal. If this occurs verify cap is tightened and
the interface between the internal cone and outer
body is free of debris.
• Add fill solution daily to maintain a good head pressure. For optimum response, this level should be maintained and not be allowed to drop more than 2-3 cm
(1-inch) below fill hole. It must cover the ceramic
found on the inner stem.
• If an erratic measurement occurs, check to see if foreign matter is seen trapped near the internal cone.
Drain and refill with fresh fill solution.
7
VIII. VIII.
Electrode PreparationElectrode Preparation
VIII.
Electrode Preparation
VIII. VIII.
Electrode PreparationElectrode Preparation
HI 4007
1. Remove protective cover from sensor tip.
2. Prepare reference electrode by filling outer electrolyte
reservoir with HI 7072.
3. Place sensor and reference electrodes into electrode
holder and connect cable connectors to meter.
HI 4107
1. Unwrap plastic film seal found over ceramic junction
on inner stem and discard. This is only used for shipping and long term storage.
2. Rinse inner stem with deionized water making certain
to wet the o-ring found on the inner stem.
Remove
Water
Deionized
3. Reassemble electrode by gently pushing the inner
assembly into the outer body, sliding spring down
cable, and screwing cap into place.
4. Remove fill hole cover and o-ring on fill hole spout.
5. Using the dropper pipette provided, add a few drops
HI 7072 fill solution to the electrode, wetting the oring and rinsing out the fill solution chamber.
8
Parafilm
6. Holding the body of the electrode gently press upper
cap with your thumb. This permits the fill solution to
drain out of the body. Release cap and verify electrode returns to its original position. (You may need to
gently assist for this to occur).
COMBINATION
CHLORIDE
HI 4107
7. Tighten the electrode cap onto the body and fill electrode body until fill solution volume is just below fill
hole.
8. Position electrode in a Hanna HI 76404 electrode
holder (or equivalent) and connect plug to meter.
9
IX. IX.
Quick Check of Electrode SlopeQuick Check of Electrode Slope
IX.
Quick Check of Electrode Slope
IX. IX.
Quick Check of Electrode SlopeQuick Check of Electrode Slope
• Connect sensors to pH/mV/ISE meter
• Place meter in mV mode.
• Place 100 mL of DIW into a beaker with stir bar.
• Place reference and measuring half-cell into prepared
sample.
• Add 1 mL of a standard (0.1 M or 1000 ppm standard) to beaker. Record the mV value when stable.
• Add an additional 10-mL of standard to the solution.
Record the mV when reading has stabilized. This
value should be less than the previous noted (more
negative).
• Determine the difference between the two-mV values.
An acceptable value for this slope is -56 ± 4 mV.
X. X.
Corrective actionCorrective action
X.
Corrective action
X. X.
Corrective actionCorrective action
• Verify protective cap has been removed.(HI 4007)
• Verify plastic film has been removed from inner
stem.(HI 4107)
• Verify electrodes are connected properly to meter and
meter is powered.
• Verify dilute standards are freshly made and stored.
Remake solutions if appropriate.
• If the sensor slope just misses the suggested slope
window, soaking the sensor in a dilute standard may
solve the problem. (Choose 10
-3
M chloride or 100
ppm standard).
• A scratched sensing surface can be polished with HI
4000-70 polishing strip. Cut off approximately 1
inch of the micro-abrasive strip. Wet the frosted side
with deionized water and place against damaged
membrane of the electrode. Place your thumb against
the shiny backing and slowly rotate back and forth
while applying gentle pressure. Continue polishing
until you are satisfied with the surface.
10
If dark deposits appears on polishing strip move the
paper slightly and continue polishing.
• If the sensor slope just misses the suggested slope
window, soaking the sensor in a standard may solve
the problem.
• If the membrane is damaged, the response becomes
extremely sluggish, or the slope of the electrode has
decreased significantly, and procedures above have
not helped, the sensor should be replaced.
XI. XI.
Direct Calibration and MeasurementDirect Calibration and Measurement
XI.
Direct Calibration and Measurement
XI. XI.
Direct Calibration and MeasurementDirect Calibration and Measurement
This method is a simple procedure for measuring many
samples. A direct reading ISE meter (HI 4222 or equivalent) determines concentration of the unknown by a direct
reading after calibrating the meter with the standards. The
meter is calibrated with two or more freshly made standards that are in the linear measurement range of the
unknowns. More calibration standards are required in nonlinear regions. Unknowns are read directly. At very low
levels of chloride, special precautions must be employed for
reproducible measurements. Water used for standards must
be chloride free and sensors and glassware must be rinsed
repeatedly with this water to prevent carry over. In the
region where the electrode response appears curved, more
calibration points are needed, and calibration will need to
be repeated more frequently.
A pH/mV meter in mV mode with semi log graph paper
may also be used. Two or more freshly prepared standards
that are in the measurement range of the unknowns are
measured in mV mode on the meter.
These values are plotted on the semi-log paper and the
points are connected to form a straight-line curve. When
samples are measured, their mV values are converted to
concentration by following the mV to the concentration axis
on the semi-log plot.
11
Procedure
1) Follow sections VIII and IX to prepare sensors for
measurement.
2) Follow section VI to prepare standards/ solution. Standards should bracket and fall within the range of
interest.
Two mL HI 4000-00 ISA, or 10 mL acetate pH buffer
or 10 mL of oxidizing reagent is added to 100 mL of
both samples and standards. Add stir bar and mix
before taking measurements. Measurements using
the oxidizing reagent must be made 10 minutes after
mixing and not permitted react longer.
3) Follow section VII; General Guidelines to optimize test
set-up.
4) During calibration it is best to start with lower concentration samples first. Wait for a stable measurement
before recording values. Slightly longer equilibrations are required at lower concentrations .
5) To prevent carry over and contamination of samples,
rinse sensors with DIW and blot dry between samples.
Typical Linearity for HI 4007 and HI 4107 Chloride
0
50
100
150
mV
200
250
300
01234567
-Log of Concentration
12
XII. XII.
Other Measurement TOther Measurement T
XII.
Other Measurement T
XII. XII.
Other Measurement TOther Measurement T
echniquesechniques
echniques
echniquesechniques
Known Addition (for Cl-)
An unknown concentration can be determined by adding a
known amount (volume and concentration) of measured
ion to a known volume of the sample. This technique is
called Known Addition. The method can use an ideal
sensor slope, but actual determined slopes at the temperature of measurement should be used if known. This method
is preprogrammed in the Hanna HI 4222 pH/ISE/mV meter,
which simplifies the method greatly.
Example: Chloride ion determination with known addition.
1. A 50 mL sample of unknown (Vsample) is placed in
a clean plastic beaker with a chloride sensor. Add 2
mL of acetate pH buffer or HI 4000-00 ISA (V
ISA)
OR if
chloride l electrode interferences are known to exist,
add 50 mL oxidizing reagent (V
). Mix well. and
ISA
record the stable mV value. (mV 1)
2. 5 mL (Vstd) of 10-3M (Cstd) standard is added to the
beaker and the mV value decreases. The unknown
chloride concentration in the original sample
(Csample) can then be determined by the following
equation.
C
=
sample
(V
(V
sample+Vstandard+VISA
(V
sample+VISA
C
standardVstandard
∆E/S
)10
T
)= V
- (VS’)
)= V
S’
V
S’
V
sample
T
3. The procedure can be repeated with a second standard addition to verify slope and operation of the
method.
13
TitrationTitration
Titration
TitrationTitration
A chloride electrode may be used as an indicator to follow
the progress of a chloride tiration with silver nitrate. The
electrode can be used in colored samples where other
indicators suffer from interferences. During the titration the
sensor follows the decrease in chloride concentration while
small additions of silver nitate titrant are added. The silver
reacts with the chloride ions forming a precipitate of silver
chloride. At the stoichiometric end point, a large change in
mV occurs. Measurements may be automated by use of
the Hanna Titrator HI 901 or titrated manually.
XIII.XIII.
pHpH
XIII.
pH
XIII.XIII.
pHpH
The HI 4107 and HI 4007 electrodes may be used in
solutions with pH values between 2 and 11. Samples that
fall beyond this range should be adjusted with acetate pH
buffer. See Section VI.
XIV. SXIV. S
torage and Care of the HI 4007 andtorage and Care of the HI 4007 and
XIV. S
torage and Care of the HI 4007 and
XIV. SXIV. S
torage and Care of the HI 4007 andtorage and Care of the HI 4007 and
HI 4107 sensorsHI 4107 sensors
HI 4107 sensors
HI 4107 sensorsHI 4107 sensors
The HI 4007 sensor can be stored in very dilute standards
(<10-4 M) for short periods of time and should be stored
dry with the protective cap on when not in use.
The model HI 4107 combination electrode can be left in
dilute standards (<10-4 M) for short time periods.
For long term storage, the electrode should be drained and
washed of salts with distilled ot deionized water. Unscrew
the upper cap and move outer sleeve up cable. Wrap the
ceramic junction on the inner stem with Parafilm® or
other sealing wrap. Place the protective cap provided over
the sensor membrane. Store dry disassembled electrode in
storage box provided with electrode.
14
XV. XV.
Conversion tablesConversion tables
XV.
Conversion tables
XV. XV.
Conversion tablesConversion tables
--
-
--
For ClFor Cl
For Cl
For ClFor Cl
Multiply byMultiply by
Multiply by
Multiply byMultiply by
Moles/L (M) to ppm (mg/L) 3.500 x 10
ppm (mg/L) to M (moles/L) 2.857 x 10
4
-5
15
MAN4107 05/08
WARRANTY WARRANTY
WARRANTY
WARRANTY WARRANTY
Hanna Instruments Ion Selective Electrodes are warranted
to be free of defects in material and workmanship for 6
months from date of purchase when used for their intended
purpose and maintained according to instructions. If they
fail to work when first used contact your dealer immediately.
Damage due to accidents, misuse, misapplication, tampering
or lack of prescribed maintenance is not covered.
Hanna Instruments reserves the right to modify the design,
construction or appearance of its products without advance
notice.
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