HI 4115
SILVER/SULFIDE
COMBINATION
HI 4015
SILVER/SULFIDE
Instruction Manual
HI 4015HI 4015
HI 4015
HI 4015HI 4015
HI 4115HI 4115
HI 4115
HI 4115HI 4115
Silver/Sulfide Ion
Selective Electrode
Half-cell
Combination
1
HI 4015 Silver/ Sulfide Half-cellHI 4015 Silver/ Sulfide Half-cell
HI 4015 Silver/ Sulfide Half-cell
HI 4015 Silver/ Sulfide Half-cellHI 4015 Silver/ Sulfide Half-cell
HI 4115 Silver/ Sulfide CombinationHI 4115 Silver/ Sulfide Combination
HI 4115 Silver/ Sulfide Combination
HI 4115 Silver/ Sulfide CombinationHI 4115 Silver/ Sulfide Combination
ElectrodeElectrode
Electrode
ElectrodeElectrode
I. I.
Introduction:Introduction:
I.
Introduction:
I. I.
Introduction:Introduction:
The Hanna HI 4015 and HI 4115 are ion selective electrodes designed for the measurement of Silver/ Sulfide ions
in aqueous solutions. The HI 4015 is a solid state half-cell
sensor that requires a separate reference. The HI 4115 is a
combination ion selective electrode.
IIII
SpecificationsSpecifications
II.
Specifications
IIII
SpecificationsSpecifications
Type: Solid State electrode with
a Silver/ Sulfide pellet.
Ion(s) measured: Silver (Ag+), Sulfide (S2-)
Measurement range: Silver 1.0 M to 1 X 10
-6
M
(107,900 to 0.11 ppm)
Sulfide 1.0 M to 1 X 10
-7
M
(32,100 to 0.003 ppm)
Theory of OperationTheory of Operation
III. III.
Theory of Operation
III.
Theory of OperationTheory of Operation
III. III.
::
:
::
The HI 4015 or HI 4115 Silver/ Sulfide electrodes are potentiometric devices used for the rapid determination of free
silver or sulfide ions. They can be used as an indicator
following the progress of a halide titration with silver nitrate. Sulfide ion determinations are made in ground waters, soils and paper liquors. The electrode functions as a
sensor or ionic conductor. The HI 4015 requires a separate
reference electrode to complete its electrolytic circuit. The HI
4115 has a double junction reference electrode incorporated in its design. The silver/ silver- sulfide 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 silver or sulfide 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
Interfering ions: Mercury must be absent.
Ions that complex with
measured species will reduce measured ion concentrations.
Operating Temperature: 0-80°C
Operating pH: 2-8 pH (For Silver)
12-14 pH (For Sulfide)
Dimensions: 12 mm (OD) X 120 mm
nominal insertion
(0.47” X 4.72”)
Connection: BNC
2
R= gas constant (8.314 J/K Mol)
n= Charge on ion (2- for sulfide), (1+ for silver)
A i=ion activity in sample
T= absolute temperature in K
F= Faraday constant (9.648 x 10
4
C/mol)
3
IV. IV.
Design elements of the HI 4015 and HI 4115Design elements of the HI 4015 and HI 4115
IV.
Design elements of the HI 4015 and HI 4115
IV. IV.
Design elements of the HI 4015 and HI 4115Design elements of the HI 4015 and HI 4115
electrodeselectrodes
electrodes
electrodeselectrodes
Cap
HI 4015
SILVER/SULFIDE
Sensor
Handle
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 use with HI 4015.
• 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.
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
VI. VI.
Solutions Required for CalibrationSolutions Required for Calibration
VI.
Solutions Required for Calibration
VI. VI.
Solutions Required for CalibrationSolutions Required for Calibration
Select appropriate Hanna Instruments standard and ISA
from the list below:
0.1 M Silver Standard, 500 mL HI 4015-01
ISA for Silver measurement, 500 mL HI 4000-00
SAOB for Sulfide measurement, 500 mL HI 4015-00
Note: For Sulfide standard, see directions that follow.
Silver Standards
For Molar solutions:
Using volumetric pipettes and glassware make serial dilutions of HI 4015-01 to approximately bracket the concentration of the samples. Standards with concentrations
-3
< 10
M should be prepared daily. Store in dark plastic
bottles.
Two mL of Hanna ISA for Halide electrodes (HI 4000-00)
should be added to 100 mL of sample or standard.
For ppm solutions:
Prepare 1078.7 ppm Silver standard by diluting HI 401501: Pipette 100 mL standard to a 1 liter volumetric flask.
Add deionized water to volume. Using additional pipettes
and glassware make serial dilutions of this 1078.7 ppm
standard to bracket the sample concentra-
4
5
tions. Standards with concentrations < 100 ppm should
be made daily.
Solutions for Sulfide Measurements
SAOB, Hanna HI 4015-00 : Add content of SAOB reagent
B bottle to the bottle with SAOB reagent A. Cap bottle
and mix well until completely dissolved. Reagent that is
brown has been oxidized and should be discarded.
Sulfide Standards:
Sulfide standards are susceptible to air oxidation and
therefore are not commercially available.
Sulfide stock solution: Weigh approximately 100 gram of
reagent grade Sodium Sulfide nonahydrate
(Na2S·9H2O) into a 1 liter volumetric flask that contains
a volume of distilled or deionized /deareated water.
Swirl to dissolve, bring to volume, then transfer to a
tightly sealed 1 L container with minimal head space
and allow solution to equilibrate overnight.
133.5 ppm standard (approximate concentration):
Transfer 5.00 mL stock solution and 250 mL Sulfide
Antioxidant buffer SAOB (Hanna HI 4015-00) to a to
500 mL volumetric flask. Mix well then bring to volume
with distilled or deionized /deareated water. Hanna HI
4015-00 SAOB, should be clear to pale straw in color
after mixing. Note: higher concentrations of standard can
also be prepared and titrated if samples are greater in
concentration. The sensor is useable from 32,100 to
0.003 ppm.
Determine exact concentration of the prepared standard
by doing a titration with Lead Perchlorate standard (user
prepared) on a weekly basis. The exact concentration of
the standard is found by titrating 10 mL of the standard
with 0.01 M Lead Perchlorate standard; (Pb(ClO4)2 ).
Pb2++ S
2-
> PbS
Use the electrode pair as an indicator for S2- to determine
the endpoint. See Section XII.
Calculate as follows:
Weekly standard in Molar concentration
VV
= Volume of the standard sulfide solution used
V
VV
s. s.
s.
s. s.
C (moles/liter)= (0.01) *
(10 mL)
VV
V
= Volume of the Lead Perchlorate titrant used to reach
VV
t t
t
t t
V
/ V
t
s.
endpoint (mL))
Weekly standard in ppm
C (ppm)= (0.01) *32.07
V
/ V
t
s.
Using volumetric pipettes and glassware make dilutions
daily from the titrated standard whose value has been
determined. Choose standards to bracket the concentration of the samples.
50 mL of HI 4000-00 ISA should be added to each 100
mL flask of standard before being brought to volume.
VIIVII
General GuidelinesGeneral Guidelines
VII.
General Guidelines
VIIVII
General GuidelinesGeneral Guidelines
• Calibration standards and sample solutions should
have the same ionic strength. ISA or SAOB 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 identically sized TFE
coated stir bars.
• Rinse electrode pair with distilled or deionized water
between samples and gently dab off using soft
disposable absorbent toweling. Do not rub sensor surface.
• Presoaking silver sensor in a dilute standard
(<10-3M) will help to optimize response.
• A scratched, pitted, or tarnished pellet surface can
cause drift, poor repeatability or a loss of low level
response. Restore optimum response can be by
removing the damaged surface with the microabrasive
strip HI 4000-70.
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