IKA LR 1000.64 pH electrode for the LR 1000 system, BNC, 0004663300

Potentiometric in-situ analysis in complex matrices

In chemical process control and pharmaceutical synthesis, the pH value is a critical thermodynamic and kinetic control parameter. The traditional method of taking samples for external pH determination distorts the metrological result due to temperature drop and oxidation, and compromises the reactor’s hermetic seal. The IKA LR 1000.64 pH electrode enables continuous, potentiometric in-situ measurement directly within the active process space. At its electrochemical core is an ion-selective glass membrane. As soon as this is immersed in the aqueous or partially aqueous medium, a galvanic interface potential is generated through the exchange of hydrogen ions (protons). The potential difference between this measuring half-cell and an internal reference system (Ag/AgCl) is recorded as a voltage signal and converted into the exact pH value by the connected transmitter using the Nernst equation.

Diaphragm mechanics in highly viscous fluids

Measurement in highly structurally viscous, pasty or particle-laden media – such as those typically processed in the LR 1000 reactor – poses a major physical challenge for conventional pH probes. Polymers or resins clog the diaphragm, blocking the essential electrical ion exchange between the reference electrolyte and the reaction medium and leading to significant measurement errors (drift). The LR 1000.64 electrode is geometrically and mechanically engineered specifically for these harsh rheological environments. The specific design of the fluid interface minimises the tendency to clog and guarantees a stable, noise-free signal flow even with extremely viscous polymers or emulsions.

System integration and thermal compensation

To maintain the reaction chamber under vacuum or inert gas during measurement, the electrode is inserted gas-tight into the lid of the LR 1000 reactor vessel via a standard ground joint. The electrical signal is transmitted via a standardised, heavily shielded BNC connector. As the galvanic potential in the Nernst equation is subject to a strict thermodynamic temperature dependence, the pH value must be continuously corrected by calculation. In the IKA LR 1000 control system, the raw signal from the LR 1000.64 electrode is coupled in real time with the in-situ data from the PT 100 temperature sensor to generate an absolutely temperature-compensated (ATC) and metrologically accurate pH output.

Seamless GLP data acquisition

The combination of the LR 1000.64 electrode and the IKA LR 1000 control system transforms the reactor into a self-contained analytical station. Acid-base titrations or pH-induced phase transitions can be recorded seamlessly. Using the IKA labworldsoft laboratory software, pH curves can be logged in synchronisation with torque and temperature trends in a tamper-proof manner. For certified laboratories subject to strict GLP or GMP guidelines, this is a fundamental prerequisite for successful QM audits.

Technical details

• Product type: Potentiometric pH electrode
• Measuring principle: Ion-selective glass membrane with reference system
• Rheological suitability: Optimised for highly viscous, pasty and particulate-laden media
• Electrical connection: Shielded BNC connector
• Compatibility: IKA LR 1000 control base station (or external pH metres)
• Thermodynamic correction: Requires external temperature compensation (ATC) within the system
• Mechanical integration: Insertion via standard threaded ports in the reactor lid
• Chemical resistance: High resistance of the glass shaft to solvents

Contents

• 1 x IKA LR 1000.64 pH electrode (incl. BNC cable)

(Important note: Standard ground adaptor, reactor vessel and transmitter are not included in the scope of delivery!)

Individual requirements & accessories

The pH electrode is a sensor only. To convert the millivolt signal into a readable pH value, you must use the IKA LR 1000 control base station (the ‘basic’ version does not include a transmitter) or a separate, high-impedance pH meter. To anchor the electrode in the reactor lid in a vacuum-tight manner, you will also need to obtain suitable standard-threaded sealing adaptors. Please contact our procurement service at any time for metrologically accurate calibration (buffer solutions) and mechanical configuration.