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Cyanide Half-Cell Ion-Selective Electrode (ISE) - HI4009

The HI4009 is a solid state, half-cell ion selective electrode (ISE) for the determination of cyanide (CN) in solution. The silver halide sensing pellet produces a potential change due to the cyanide ion exchange between the inorganic pellet membrane and the sample. The internal sensing elements are housed within a durable epoxy body.

The HI4009 is ideal for a variety of applications in plating, wastewater, and agriculture.

Solid state sensor

Detection from 0.026 to 260 mg/L CN

For use with HI5315 reference half-cell


The HI4009 cyanide selective electrode is a potentiometric half-cell sensor housed within an epoxy body. The internal elements are isolated from the sample by a compressed silver halide sensing membrane. This solid state sensor requires a separate reference electrode to complete the measurement system.

Hanna’s solid state half-cell ISEs are designed for use with the HI5315 reference half-cell. The reference half-cell features a cone style junction. The skirted cone geometry of the reference forms the liquid junction with the test solution at the tip of the junction cone, producing a highly stable reference potential and consistent flow rates of electrolyte into the solution. A simple press of the top portion of the ISE makes it easy to empty the electrolyte fill solution and replace when necessary.

For the HI4009 to measure cyanide accurately, it is important that the ionic strength of the standards and sample be adjusted to a high and constant value with the cyanide ionic strength adjuster (ISA) solution. The alkaline ISA ensures that the activity coefficient is constant so the concentration of free cyanide ions can be measured. Measuring all solutions with a constant ionic strength reduces the margin of error between measurements. The HI4009 cyanide solid state ISE can measure from 1µM (0.026 mg/L) to 0.01M (260 mg/L).

Conversion Table for CN


moles/L (M) to ppm (mg/L)

2.602 x 104

ppm (mg/L) to M (moles/L)

3.843 x 10-5

Features at-a-glance

Fixed Sensing Modules – Solid state half-cell ISEs are electrodes that detect free ions in a solution. The highly insoluble, compressed sensing pellet is attached to the HI4009 cyanide half-cell by a fixed sensing module for ease of use.

Durable Epoxy Body – The probe body of the cyanide half-cell ISE is composed of durable epoxy resin.

BNC Connection – The HI4009 has a universal BNC connector for easy connection to any benchtop meter with a female BNC probe input.

Theory of Operation

A solid state sensor electrode develops a voltage due to the ion exchange that occurs between the solution and the inorganic membrane. An equilibrium occurs due to the highly limited solubility of the membrane material in the sample. When the ionic strength of the solution is fixed by the addition of ISA, the voltage is proportional to the concentration of free ions in solution.

Additional information

Weight 0.25 kg


Temperature Range

0 to 80 °C


SKU HI4009
Name Cyanide Half-Cell Ion-Selective Electrode (ISE) – HI4009
Description solid state; half-cell
Measurement Range Cyanide (CN) 0.01M to 1 10-6M, 260 to 0.026 mg/L (ppm)
Temperature Range 0 to 80 °C
Body Material epoxy
Optimum pH Range > pH 11
Body Length/Overall Length 120 mm
Outer Diameter 12 mm
Cable coaxial; 1 m (3.3’)
Connector Type BNC
Notes Approximate Slope -56 mV


Cyanide Half-Cell Ion-Selective Electrode (ISE) – HI4009