Hi 4014 p – Hanna Instruments HI 4014 User Manual

Page 2

III.

III. Theory of Operation:

Theory of Operation:

The HI 4014 and HI 4114 potassium electrodes are poten-
tiometric devices used for the rapid determination of free
potassium ions in water, soft drinks, wine, and soils. The
electrode functions as a sensor or ionic conductor. HI 4014
requires a separate reference electrode to complete its elec-
trolytic circuit. HI 4114 is a combination electrode with a
reference electrode incorporated in its design. The PVC mem-
brane used on the sensor is impregnated with the organic
ion exchanger valinomycin. This carrier ionophore

encloses

the ion like a cage. The outside of the ionophore molecule
is uncharged and it can freely diffuse through the lipid
layers of the membrane producing a charge imbalance
between the test solution and internal cell of the sensor.
This produces a voltage that changes in response to the
sample

’s ion activity. When the ionic strength of the sample

is fixed, the voltage is proportional to the concentration of
potassium ions in solution. The sensor follows the Nernst
Equation:

E = E

+ 2.3 RT/nF log A

ion

E = observed potential

= Reference and fixed internal voltages

R = gas constant (8.314 J/K Mol)

n= Charge on ion (equivalents/mol) (1+)

ion

= ion activity in sample

T = absolute temperature in

F = Faraday constant (9.648 x 10

C/equivalent)

HI 4014 P

HI 4014 Potassium half-cell

otassium half-cell

HI 4114 P

HI 4114 Potassium combination electrode

otassium combination electrode

I .

I .I.

I .

Introduction

he Hanna HI 4014 and HI4114 are ion selective elec-

trodes designed for the measurement of potassium ions in
aqueous solutions. They utilize a replaceable sensing mod-
ule that contains an organic polymer membrane that is
sensitive to potassium. HI 4014 is a half-cell electrode that
requires a separate reference.
HI 4114 is a combination ion selective electrode.

IIII

IIII. Specifications

Specifications

Type:

PVC membrane with
organic ion exchanger

Ion measured:

Potassium (K

)

Measurement range:

1M to 1X 10

-6

39100 to 0.039ppm

Operating Temperature:

0-40

°C

Operating pH:

1.5 to 12.0 pH

Dimensions:

12 mm (OD)(0.47

”) X

120 mm (4.72

”)

(insertion)

Connection:

BNC

Interference:
Organic solvents and cationic detergents must be absent.
Ratio of interfering ion to K

must be below

10 for NH

300 for Li

2000 for Na

2000 for Ca

This manual is related to the following products:

HI 4114