LabSen® 551 Professional Combination pH Electrode for Direct Soil pH Testing, BNC Connector


Backed by proprietary Swiss sensor technology and materials, the LabSen 551 Combination pH Spear Sensor Electrode is designed for testing soil directly.

  • Proprietary pH sensor technology and materials from Switzerland
  • Special LabSen Spear pH sensor tip, ideal for direct soil pH testing. No more slurry making.
  • PVC housing, ideal for use in harsh environments
  • Polymer Electrolyte - No more clogged junction
  • Long-Life Reference System, improving the stability of reference electrode and prolong the service life of the electrode

Long-Life Reference System - The LabSen 551 pH electrode adopts a long-life reference system, which is composed of a glass tube, AgCl, and a reference silver wire. The top end of the slim glass tube is stuffed with cotton, which prevents the reaction between AgCl and electrolyte when the temperature changes. It improves the stability of reference electrode and extends the service life of the electrode.

Polymer Electrolyte - The solid polymer electrolyte makes the electrode hard to be contaminated and maintenance-free.

Special Glass Membrane - The LabSen 551 pH electrode adopts a spear sensor tip, which is ideal for directly testing semi-solid samples like soil.

The electrode uses a BNC connector, compatible with any pH meters that use BNC connectors, such as Apera Instruments PH700, PH850, PH8500, PH910, PH950, MP511, PH800, PC850, PC8500, PC910, PC950, PC800 and PC820. The temperature sensor is not built-in. Users need to have a separate temperature (ex: Apera Instruments MP500) probe to enable ATC or manually input temperature to realize temperature compensation.

The electrode is backed up with a 6-month warranty by Apera Instruments.

Technical Specifications
Range: pH 0 to 14
Temperature Range: 0 - 80 °C (32 - 176 °F)
Temperature Sensor: No
Material: PVC
Junction: Ceramic/Single Pore
Referenzsystem: Long Life
Electrolyte: Polymer
Membrane Shape: Spear
Connector: BNC
Cable length: 1 m
Length: 90 mm
Diameter: 15 mm (Measuring tip: 6 mm)