Silver/Sulfide Half-Cell Ion Selective Electrode (ISE)

The HI4015 silver/sulfide 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/silver sulfide 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.

Measuring all solutions with a constant ionic strength reduces the margin of error between measurements. The HI4015 silver/sulfide solid-state ISE can measure silver from 1µM (0.11 mg/L) to 1M (107,900 mg/L) and sulfide from 0.1µM (0.003 mg/L) to 1M (32,100 mg/L).

Silver (Ag⁺)

For the HI4015 to measure silver accurately, it is important that the ionic strength of the standards and sample be adjusted to a high and constant value with the halide ionic strength adjuster (ISA) solution. The ISA ensures that the activity coefficient is constant so the concentration of free silver ions can be measured.

Conversion Table for Ag⁺

Sulfide (S^2-)

For accurate sulfide measurement, it is important that sulfur is released from hydrogen and that sulfide oxidation is prevented with the sulfide antioxidant buffer solution (SAOB). The SAOB ensures that the solution pH is above pH 12, reducing the effect of interfering ions and releasing sulfur from hydrogen ions. SAOB also acts to stabilize the activity coefficient so the concentration of free sulfide ions can be measured.

Conversion Table for S^2-