Cyanide Combination Ion Selective Electrode (ISE) - HI4109
The HI4109 is a solid state, cyanide combination 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 polyetherimide (PEI) body. The HI4109 is ideal for a variety of applications in plating, wastewater, and agriculture.
- Solid state sensor
- Skirted cone geometry
- Detection from 0.026 to 260 mg/L CN-
The HI4109 cyanide selective electrode is a complete potentiometric cell that contains a silver/silver chloride (Ag/AgCl) reference housed within a PEI plastic body with a potassium nitrate electrolyte. The internal elements are isolated from the sample by a compressed silver halide sensing membrane.
Hanna’s solid-state combination ISEs are designed with a cone style junction. The skirted cone geometry of the sensor 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 HI4109 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 HI4109 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
Fixed Sensing Modules
- Combination solid-state ISEs are electrodes that detect free ions in a solution. The highly insoluble, compressed sensing pellet is attached to the electrode by a fixed sensing module for ease of use.
Durable PEI Body
- The probe body is composed of durable polyetherimide (PEI) plastic.
- The HI4109 has a universal BNC connector for easy connection to any benchtop meter with a female BNC probe input.
Theory of OperationA 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.
|Type||solid state; combination|
|Optimum pH Range||>11|
|Temperature Range||0 to 80°C|
|Cable||1 m coaxial|
|Common Applications||determination of free cyanide ions in plating baths, waste water and in plant and soil samples|