The absolutely sealed 3H-type cell combines a separate reference compartment with vacuum and a controlled gas atmosphere. The reference electrode sits in a separate third compartment connected to the working compartment through a Luggin capillary with a tip opening below 0.2 mm (manufacturer data). Bringing the tip close to the working electrode reduces the ohmic (iR) error in the measured potential; do not place the tip closer than about twice the capillary diameter. Agar can be added to the capillary to slow electrolyte exchange.

The reference compartment is closed with an internally threaded cap. Keep it closed during measurement; otherwise liquid flows between compartments by the communicating-vessels effect. The flanges of the two compartments are joined with a chain clamp; opening the clamp lets you change the membrane in minutes.

In the absolutely sealed cell the electrodes plug into socket (jack) connections inside the lid, isolating the system completely from the outside. With valves fitted, the cell can be evacuated (below −100 kPa) or operated under slight pressure (max. 0.5 MPa, manufacturer data). The electrodes are made to fit this cell and must be ordered together with it.

The body is made of borosilicate glass 3.3, which has low thermal expansion (3.3 × 10⁻⁶ K⁻¹) and the highest resistance classes against water (HGB 1) and acids (S 1). Avoid sudden temperature differences above 120 °C to reduce the risk of breakage.

In the jacketed (double-layer) version an outer water jacket surrounds the inner cell. Water from a circulating thermostatic bath flows through the jacket via hose connections and keeps the electrolyte at a constant temperature during the measurement. Because the inner glass of the jacketed body is thinner, do not pressurize this version; vacuum and gas purging can be used.

Key Features

Jacketed (double-layer) body: constant electrolyte temperature with a circulating bath
Three-compartment, absolutely sealed glass cell
Separate reference compartment with Luggin capillary
Socket-connected electrodes; vacuum and purging through valves
Replaceable membrane with chain clamp
Seven volumes from 5-10 mL to 250 mL

Technical Specifications

Cell type	Three-compartment (3H), absolutely sealed
Temperature control	Water jacket for a circulating thermostatic bath
Body	Borosilicate glass 3.3
Luggin capillary	Tip opening ≤ 0.2 mm (manufacturer data)
Electrode connection	Socket (jack) in the lid
Vacuum / pressure	Below −100 kPa; slight pressure max. 0.5 MPa (manufacturer data)
Volume options	5-10 mL, 30 mL, 50 mL, 100 mL, 150 mL, 200 mL, 250 mL
Not included	Electrodes and membrane (sold separately)

A sampling port can optionally be added to the cell body; please mention it in your quotation request.

Valves are not included in the price. The valve kit for gas purging and vacuum is offered as a separate product (LM-EC-CELL-VALVE) and is ordered together with the cell.

Electrodes and membranes shown in the photos are for illustration only and are not included in the price. Compatible reference, counter and working electrodes and membranes are available in the Electrodes category of our site.

For volumes, dimensions or port layouts other than those listed, you can request a custom-made quotation through the Quotation Form.