Hanna Instruments HI 4004 User Manual

HI 4104

CALCIUM

COMBINATION

HI

4000-50

SENSOR HANDLE

Instruction Manual

HI 4004HI 4004

HI 4004

HI 4004HI 4004
HI 4104HI 4104

HI 4104

HI 4104HI 4104

Calcium Ion

Selective Electrode

Half-cell

Combination

1

HI 4004 Calcium Half-cellHI 4004 Calcium Half-cell

HI 4004 Calcium Half-cell

HI 4004 Calcium Half-cellHI 4004 Calcium Half-cell
HI 4104 Calcium Combination ElectrodeHI 4104 Calcium Combination Electrode

HI 4104 Calcium Combination Electrode

HI 4104 Calcium Combination ElectrodeHI 4104 Calcium Combination Electrode

I. I.

Introduction:Introduction:

I.

Introduction:

I. I.

Introduction:Introduction:
The Hanna HI 4004 and HI 4104 are ion selective elec­trodes designed for the measurement of calcium ions in
aqueous solutions. They utilize a replaceable sensing mod­ule that contains an organic polymer membrane that is
sensitive to calcium ions. The HI 4004 is a half-cell elec­trode that requires a separate reference. The HI 4104 is a
combination ion selective electrode.

IIII

SpecificationsSpecifications

II.

Specifications

IIII

SpecificationsSpecifications

Type: PVC membrane with

organic ion exchanger

Ion measured: Calcium (Ca

2+

)

Measurement range: 1.0 M to 3 X 10

-6

M

40080 to 0.12 ppm
Interference:
Organic solvents and cationic detergents must be absent.
Ratio of interfering ion to Ca

2+

must be less than the

ratio indicated below:

15000 for Na+sodium
7000 for Mg3+magnesium
700 for Ni2+nickle
300 for Fe

2+

ferrous

250 for Al3+aluminum

2+

+

4

-

ammonium

lead

200 for NH
35 for Cu2+cupric

0.001 for Pb
Operating Temperature: 0-40°C
Operating pH: 4 to 10 pH (see Section

XIII)

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 4004 and HI 4104 calcium electrodes are potentio­metric devices used for the rapid determination of free cal­cium ions in water, sea water and beverages. The electrode
functions as a sensor or ionic conductor. The HI 4004
requires a separate reference electrode to complete its elec­trolytic circuit. The HI 4104 is a combination electrode with
a Ag/AgCl reference electrode with gel stabilized Cl- electro­lyte in it’s inner chamber. The external reference chamber
is refillable. The PVC membrane used on the sensor is
impregnated with the organic ion exchanger.
This organic ion exchanger is considered a carrier ionophore
in that it is capable of shielding and carrying the charged
calcium ion in it’s polar cage freely through the apolar
regions of the membrane. A charge imbalance developes
between the test solution and internal cell of the sensor.
This voltage changes in response to the sampleís ion activ­ity. When the ionic strength of the sample is fixed, the
voltage is proportional to the concentration of nitrate ions in
solution. The sensor 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 (2+)
A

= ion activity in sample

ion

T = absolute temperature in K
F = Faraday constant (9.648 x 104 C/equivalent)

3

IV. IV.

Design elements of the HI 4004 and HI 4104Design elements of the HI 4004 and HI 4104

IV.

Design elements of the HI 4004 and HI 4104

IV. IV.

Design elements of the HI 4004 and HI 4104Design elements of the HI 4004 and HI 4104

electrodeselectrodes

electrodes

electrodeselectrodes

Cap

HI

4000-50

HANDLE
R

SENSO

Sensor
Handle

O-Ring
Sensing

module

Upper Cap
Upper

Threads
O-Ring

Ceramic Junction
on Inner Stem

Liquid junction

Spring

Fill Hole

O-Ring and
Plug

Outer Sleeve

Sensing Module

4

V. V.

Equipment required:Equipment required:

V.

Equipment required:

V. V.

Equipment required:Equipment required:

• The HI 4004 requires the Hanna HI 5315 Double

junction reference electrode with HI 7082 as external
electrolyte.

• 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

magnetic stirring bars (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

Standards for Calcium Measurements

0.1 M calcium standard,500 mL HI 4004-01
Ionic Strength Adjuster
ISA, 500 mL HI 4004-00
Conditioning and Storage Solution
Calcium storage solution, 500 mL HI 4004-45
Using volumetric pipettes and glassware make dilutions to
bracket the concentration of the samples. Store samples in
plastic bottles. Standards with concentrations < 10

-3

should be prepared daily.
Two mL of Hanna ISA HI 4004-00 should be added to
100 mL sample or standard.

M

VIIVII

General GuidelinesGeneral Guidelines

VII.

General Guidelines

VIIVII

General GuidelinesGeneral Guidelines

• Ensure the o-ring is installed on modules before

screwing into the sensor handle or inner stem.

O-Ring

5

• Due to shipping or storage the internal solution inside
the PVC modules may have developed an air pocket
near the membrane. Gently shaking the sensor down
(like the old style mercury thermometer) will place the
internal solution next to the membrane.

• Presoaking the Calcium sensor in HI 4004-45
solution for at least half-hour before calibration will
help to optimize the sensor response.

• Do not leave your sensors in standard or samples

with ISA for long periods of time.

Note: The electrode membrane will develop a opaque
appearance when it becomes wetted. This is normal.

• Calibration standards and sample solutions should
have the same ionic strength. ISA should be added to
both samples and standards.

• Calibration standards and sample solutions should
be at same temperature.

• Thermally insulate solution vessel from magnetic stir­rer.

• Calibration standards and sample solutions should
be stirred at the same rate using identical sized TFE
coated stir bars.

• Rinse electrodes with distilled or deionized water be­tween samples and gently dab dry with lab wipe or
other soft disposable absorbent toweling. Do not rub
the sensing surface.

• Check for gas bubbles that may form near sensing
surface (due to solution temperature changes). Tap
off gently.

• Avoid large changes in temperature (thermal shock)
as it may damage the sensor.

6

Additional HI 4104 guidelines

• Remove the protective plastic wrap that covers the
ceramic junction before assembling sensor for the first
time.

• Add reference HI 7082 fill solution to bottom of fill
hole or empty and refill fill solution daily before us­ing.

• 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 filling solution daily to maintain a good head
pressure. For optimum response, this level should be
maintained and not be allowed to drop more than 2­3 cm (1-inch) below fill hole.

• Do not use an electrode if crystallized salts are visible
inside the electrode. Drain electrode, disassemble and
rinse internal body with deionized water. Reassemble
and refill with fresh fill solution.

• If an erratic measurement occurs, check to see if for­eign matter is seen trapped near the internal cone.
Drain by depressing the electrode cap then refill with
fresh fill solution.

VIII.VIII.

Electrode PreparationElectrode Preparation

VIII.

Electrode Preparation

VIII.VIII.

Electrode PreparationElectrode Preparation
HI 4004
The Hanna HI 4004 is a 2 piece design comprised of a
sensor handle (HI4000-50) and a sensing module (HI
4004-51).

1. Remove sensing module from shipping vial. Do not

touch the sensing membrane with the “H” hole pat­tern on it.

2. Screw the module into the sensor handle finger tight.

Do not overtighten.

7

HI

4000-50

E
L
D
N
A
H

R
O
S
N
E
S

3. Holding the assembled electrode at the cable end,
shake the sensor to ensure internal fill solution that
may have separated during shipping is in contact
with inner membrane surface.

4. Prepare HI 5315 reference electrode by filling electro­lyte reservoir with HI 7082 fill solution.

5. Place sensor and reference electrodes into electrode
holder and connect cable connectors to meter.

6. Soak the Calcium electrodes membrane in HI 4004-45
conditioning solution or a calcium standard (0.01M)
without ISA before calibration.

HI 4104
The Hanna HI 4104 is shipped disassembled. The
sensing module is found in the glass storage vial.

1. Unwrap Parafilm® seal found over ceramic junction
on inner stem and discard. This is only used for ship­ping or long term storage.

2. Remove sensing cone from shipping vial. Do not touch
the sensing membrane with the “H” hole pattern on
it.

3. Screw the cone into the inner stem finger tight. Do not
over tighten.

8

Remove

Water

Deionized

Parafilm

Install
sensing
module

4. Rinse inner stem with deionized water making certain
to wet o-ring found on the inner stem.

5. Reassemble electrode by gently pushing the inner
assembly into the outer body, sliding spring down
cable, and screwing cap into place.

6. Remove fill hole cover and o-ring on fill hole spout.

Using the dropper pipette provided, add a few drops

HI 7082 fill solution to the electrode. Invert the elec­trode to wet the o-ring and rinse the fill solution cham­ber.

9

7. 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

CALCIUM

HI 4104

8. Tighten the electrode cap onto the body and fill elec­trode body until fill solution volume is just below fill
hole.

9. Position electrode in a Hanna HI 76404 electrode
holder (or equivalent) and connect BNC connector to
meter.

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 electrode(s) to pH/mV/ISE meter

• Place meter in mV mode.

• Place 100 mL of deionized water into a beaker with

stir bar.

• Place reference and measuring half-cell or combina­tion electrode into prepared sample.

• Add 1 mL of a 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

10

value should be more positive than the previous
value noted.

• Determine the difference between the two mV values.
An acceptable value for this slope is

26 ± 4 mV (20-25°C).
X. X.

Corrective actionCorrective action

X.

Corrective action

X. X.

Corrective actionCorrective action

• Verify module has been screwed into sensor handle or
inner stem.

• Verify Parafilm® seal has been removed from ce-
ramic junction (HI 4104 or HI 5315 reference).

• Verify fill solution has been added to reference cham­ber.

• Verify electrodes are connected properly to meter and
meter is powered.

• Verify dilute standards are freshly made and stored.
Remake solutions if appropriate. Store in plastic
bottles.

• If the reading is jumpy or unstable, shake sensor
down (see section VII).

• If the sensor slope just misses the suggested slope
window, soaking the sensor in a standard solution
without ISA 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 module should be replaced.

For HI 4004

1. Dry off module and sensor handle.

2. Unscrew sensing module and replace with a new one.
(HI 4004-51).

3. Soak new module in calcium solution to condition it
before calibration.

For HI 4104

1. Drain the fill solution by depressing cap. Rinse elec­trode with distilled or deionized water. Drain.

11

2. Unscrew upper cap and slide down cable toward con­nector.

3. Move spring and outer body down cable also.

4. Dry off inner stem and module with a soft tissue.

5. Hold inner stem and unscrew module and replace
with a new one. (HI 4104-51).

6. Reassemble electrode (see section VII), and refill with
electrolyte. Soak new membrane in calcium solution
without ISA to condition before calibration.

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. Add
HI 4004-00 to adjust ionic strength at a dose of 2 mL of per
100 mL sample or standard. The meter is calibrated using
freshly made standards that are in the measurement range
of the unknowns. Unknowns are read directly. In the region
where the electrode calibration becomes less linear, more
calibration points are needed, and calibration will need to
be repeated more frequently.

A pH/mV meter in mV mode and 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.

12

Procedure:
Follow sections VIII and IX to prepare electrodes for mea­surement.

1) Follow section VI to prepare standards/ solution. Stan­dards should bracket and fall within the range of
interest. Standards and solutions should be at the
same temperature.

2) 2 mL of HI 4004-00 is added to 100 mL of both
samples and standards.
Add stir bar and mix before taking measurements.

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 reading before
reading/ recording values. Permit longer equilibra­tion times at these levels (3 or 4 minutes).

To prevent carry over and contamination of samples, rinse
sensors with deionized water and remove moisture with
absorbant tissue between samples.

Typical HI 4004 and HI 4104 Linearity

100

80
60
40
20

mV

0

-20

-40

-60

-80
0123456

-Log of Molar Co ncentratio n

13

XII. XII.

Other Measurement TOther Measurement T

XII.

Other Measurement T

XII. XII.

Other Measurement TOther Measurement T

Known additionKnown addition

Known addition

Known additionKnown addition

echniquesechniques

echniques

echniquesechniques

An unknown concentration can be determined by adding a
known volume and concentration of Ca2+ standard to the
sample. mV values are noted before and after the addition
of standard (∆E). An ideal sensor slope can be used in the
equation but actual determined slopes at the temperature
of measurement should be used if known (S). This method
is preprogrammed in the Hanna HI 4222 pH/ISE/mV meter,
which simplifies the method greatly.
Example:
Calcium ion determination with known addition.

1. A 50 mL sample of unknown (V

) is placed in a

SAMPLE

clean plastic beaker with an electrode (s). One mL of
ISA is added to the sample and permitted to mix. mV
1 is recorded.

2. 10 mL (V

STANDARD

) of 10

-1

M (C

) standard is added

STANDARD

to the beaker and the mV value increases. (Note: for
other concentration samples, add a known volume
and concentration of standard to produce approxi­mately 30 mV change).
The unknown calcium concentration in the original
sample (C

) can then be determined by using the

SAMPLE

equation that follows.

3. The procedure can be repeated with second standard
addition to verify slope and operation of the method.

C

=

sample

(V

sample+Vstandard+VISA

(V

XIII.XIII.

pH and InterferentspH and Interferents

XIII.

pH and Interferents

XIII.XIII.

pH and InterferentspH and Interferents

C

standardVstandard

)10

T

∆E/S

(V

sample+VISA

- (VS’)

)= V

S’

)= V

V
V

T

S’

sample

HI 4004/ HI 4104 calcium electrodes can operate over a

14

pH range of 4-10 . The electrode responds to free calcium
ions only. Precipitates with oxalate, carbonate, phosphate
and complexes with hydroxide, sulfate, and bicarbonate
reduce measureable calcium from solution. Using Known
Addition (section XII) with complexing reagents and pH
adjustments may permits total calcium to be measured.
Limiting the length of time of exposure to samples containing
interferences will prolong useful life of your electrode. If
sensor has been exposed to ions above recommended levels,
soaking in pure calcium solutions without ISA or HI 4004­45 will aid recovery of function.

XIV.XIV.

Storage and Care of the HI 4004 andStorage and Care of the HI 4004 and

XIV.

Storage and Care of the HI 4004 and

XIV.XIV.

Storage and Care of the HI 4004 andStorage and Care of the HI 4004 and

HI 4104 electrodesHI 4104 electrodes

HI 4104 electrodes

HI 4104 electrodesHI 4104 electrodes
The HI 4004 sensor can be stored in HI 4004-45 for short
time periods. For long term storage, unscrew sensing mod­ule from sensor handle and store dry in the shipping vial.
The model HI 4104 combination electrode can be left in
HI 4004-45 for short time periods. If the electrode will be
used frequently and needs to be ready for use, take mea­sures to prevent evaporation of fill solution. Top off fill
solution, replace o-ring, fill hole cover on the fill hole open­ing, and place sensor in HI 4004-45 storage and condi­tioning solution. Store electrode upright. Prior to use, drain
electolyte chamber and refill with fresh HI 7082 fill solu­tion.
For long term storage, the electrode should be drained,
disassembled and washed of salts with deionized water.
Wrap the ceramic junction in Parafilm® or other sealing
wrap. Unscrew the module and store dry in the shipping
vial. Refrigeration of module will extend its life. Store dis­assembled electrode in storage box provided with electrode.

XV. XV.

Conversion tablesConversion tables

XV.

Conversion tables

XV. XV.

Conversion tablesConversion tables

Multiply by Multiply by

Multiply by

Multiply by Multiply by

2+

(mg/L) 40080

Moles/L (M) Ca

2+

to ppm Ca

ppm (mg/L) to M (moles/L) 2.49 X 10

15

-5

MAN4104 07/06R1

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.

16