HI-1151B Refillable combination pH electrode

The polypropylene cap offers high chemical resistance and the internal seals isolate the connection of the internal electrode indicating wire, providing long-lasting durability against solvents. To further protect the internal portion of the pH electrode, a resin is used to reinforce the seals.

Hanna Instruments offers a wide variety of pH electrodes that are designed for many different applications. The type of glass used for sensing pH, bulb shape, body material, type of junction, type of reference and electrolyte used are just some of the design considerations.

The HI-1151B uses high temperature glass, spherical bulb, glass body, single ceramic junction, double reference and is refillable with a non-aqueous electrolyte as it is supplied empty.

High Temperature Glass Formulation

The measurement of pH at very high temperatures is detrimental to the sensitive glass bulb and will shorten the life of it. A pH electrode with general purpose (GP) glass will have a resistance of 100 megaohms at 25°C while the resistance of high temperature glass is around 400 megaohms at 25°C. As the HI-1151B is used at elevated temperatures the resistance decreases to approach the that of GP glass. The HI-1151B is suitable to use with samples that measure from 0 to 100°C.

Spherical Glass Tip

The spherical bulb is for general purpose use. Other tip shapes include conic for penetration and flat tip for surface measurements.

Glass Body

The glass body is ideal for laboratory use. The glass is resistant to many harsh chemicals and is easily cleaned. The glass body also allows for a fast transfer of heat to the internal reference electrolyte. The mV generated by the reference cell is temperature dependent. The faster the electrode reaches equilibrium, the steadier the reference potential. The internal seals isolate the connection of the internal electrode indicating wire providing long-lasting durability against solvents. To further protect the internal portion of the pH electrode, a resin is used to reinforce the seals.

Single Ceramic Double Junction Reference

The HI-1151B is a double junction design. pH electrodes are available as single junction or double junction. See below for a complete description of the differences. The junction also known as a salt bridge is a necessary component of the electrical circuit. The movement of ions must flow through the junction for a steady reading. The outer reference has a single ceramic frit. The ceramic is a porous material that is easily fused with the glass body and has a similar expansion coefficient. A single ceramic junction has a flow rate of 15-20 μL/hour. Other junction types are available with higher flow rates and made with different materials.

Refillable

The HI-1151B is a refillable probe. It is supplied empty in the first instance. Since it is a double junction pH electrode, the fill solution of your choice, dependent on your application should be non-aqueous. Clogging of the junction will result in drifty and erratic readings. The polypropylene cap offers high chemical resistance.

BNC Connector

The HI-1151B uses a BNC connector. This type of connector is universal in that it can be used on any pH meter that has the female BNC probe input. Other types of connectors include DIN, screw type, T-type, and 3.5mm to name a few. These types of connectors tend to be proprietary for a particular type of meter and are not interchangeable.