Hanna Instruments

The HI-4003 cadmium ion selective electrode is a potentiometric half-cell sensor housed within an epoxy body. The internal elements are isolated from the sample by a compressed cadmium sulphide/silver sulphide 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 HI-5315 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 HI-4003 to measure cadmium accurately, it is important that the ionic strength of the standards and sample be adjusted to a high and constant value with the HI-4000-00 ionic strength adjuster (ISA) solution. The ISA ensures that the activity coefficient is constant so the concentration of free cadmium ions can be measured. Measuring all solutions with a constant ionic strength reduces the margin of error between measurements. The HI-4003 cadmium solid state ISE can measure from 0.1µM (0.01 mg/L) to 0.1M (11,200 mg/L).