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-