Hanna Instruments HI 4003 User Manual

HI 4103

CADMIUM

COMBINATION

HI 4003

CADMIUM

Instruction Manual

HI 4003HI 4003

HI 4003

HI 4003HI 4003
HI 4103HI 4103

HI 4103

HI 4103HI 4103

Cadmium Ion
Selective Electrode

Half-cell
Combination

1

HI 4003 Cadmium Half-cellHI 4003 Cadmium Half-cell

HI 4003 Cadmium Half-cell

HI 4003 Cadmium Half-cellHI 4003 Cadmium Half-cell
HI 4103 Cadmium Combination ElectrodeHI 4103 Cadmium Combination Electrode

HI 4103 Cadmium Combination Electrode

HI 4103 Cadmium Combination ElectrodeHI 4103 Cadmium Combination Electrode

I. I.

Introduction:Introduction:

I.

Introduction:

I. I.

Introduction:Introduction:
The Hanna HI 4003 and HI 4103 are ion selective elec­trodes designed for the measurement of cadmium ions in
aqueous solutions. The HI 4003 is a solid state half-cell
sensor that requires a separate reference. The HI 4103 is a
combination ion selective electrode.

IIII

SpecificationsSpecifications

II.

Specifications

IIII

SpecificationsSpecifications

Type: Solid State electrode with

a Cadmium sulfide/ silver
sulfide membrane.

++

2

+

Ion(s) measured: Cadmium (Cd

++

)

Measurement range: 0.1 M to 1X 10

-7

M

11,200 to 0.01 ppm

Interfering ions: Silver and mercury must
be absent. Any ion that forms a more insoluble sulfide than
cadmium sulfide will interfere with the electrode response.
These include lead (Pb2+)and cupric ions (Cu2+). Oxidation
of the cadmium surface by ferric ion( Fe3+) will severely
poison the electrode. Ions that can form complexes with
cadmium ions will reduce the measured concentration.
Examples include bromide, chloride and EDTA.

Operating Temperature: 0-80°C

Operating pH: 2 to12 pH
concentration dependant

(4.5-7.5 recommended)

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 4103 or HI 4103 cadmium electrodes are potentio­metric devices used for the rapid determination of free cad­mium ions in samples and as a detector for the titration of
cadmium with EDTA.

Cadmium sensors are “electrodes of

the third kind” because they detect cations which also form
low-solubility salts with sulfide anions that also form low­solubility salts with silver.

The electrode functions as a sensor or ionic conductor. The
HI 4003 requires a separate reference electrode to complete
its electrolytic circuit. The HI 4103 incorporates a reference
electrode. The mixed cadmium sulfide/ silver sulfide mem­brane produces a potential change due to changes in the
sample’s cadmium ion activity. When the ionic strength of
the sample is fixed by the addition of ISA, the voltage is
proportional to the concentration of cadmium 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 volt coulomb/K Mole)

n= Charge on cadmium ion (2+)

A i=ion activity in sample

T= absolute temperature in K

F= Faraday constant (9.648 x 104 coulomb/mole)

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IV. IV.

Design elements of the HI 4003 and HI 4103Design elements of the HI 4003 and HI 4103

IV.

Design elements of the HI 4003 and HI 4103

IV. IV.

Design elements of the HI 4003 and HI 4103Design elements of the HI 4003 and HI 4103

electrodeselectrodes

electrodes

electrodeselectrodes

Cap

HI 4003

Sensor
Handle

Sensing
Membrane

Upper Cap

Upper
Threads

O-Ring

CADMIUM

Spring

Fill Hole

Ceramic Junction
on Inner Stem

Liquid junction

O-Ring and
Plug

Outer Sleeve

Sensing
Membrane

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V. V.

Equipment required:Equipment required:

V.

Equipment required:

V. V.

Equipment required:Equipment required:

• Hanna HI 5315 Double Junction Reference Electrode

with HI 7072 Fill Solution for use with HI 4003 half­cell.

• 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 TFE

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 Cadmium Measurements

0.1 M cadmium standard, (500 mL) HI 4003-01
ISA, (500 mL) HI 4000-00

For direct cadmium measurements- Using volumetric pi­pettes and glassware, make dilutions of HI 4003-01 to
bracket the concentration of the samples. Note: 0.1M cad­mium standard is equivalent to 11,200 ppm. Standards
with concentrations < 10

-3

M (112 ppm) should be pre­pared daily. Store in tightly closed plastic bottle. To 100
parts standard or sample add 2 parts of ISA.
Please note: cadmium compounds are toxic by ingestion or
skin contact. Take appropriate precautions.

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