Laboratory electrodes and probes: which parameters can they measure?

Essential for any physico-chemical measurement, electrodes and probes convert ionic or optical signals into data your instrument can use. Our range covers routine and research applications: pH electrodes with or without ATC, Redox (ORP) electrodes, ISE for specific ions, optical or electrochemical dissolved O? probes, 2- or 4-pole conductivity probes, and temperature Pt100/Pt1000 sensors (thermocouple or NTC). Glass or polymer body, single/double junction, BNC/DIN connectivity, and leads: whatever your sample matrix, you get a reliable, durable and traceable solution.

What types of electrodes and probes are available, and how do you choose the right one?

The pH electrodes are available with or without a temperature sensor (ATC). ATC versions simplify temperature compensation and speed up stabilisation. Choose double-junction for complex matrices (wastewater, proteins), refillable for longevity, and a tip bulb/spear/micro to suit the sample. Store in KCl 3 M (never in deionised water).

Redox electrodes (platinum or gold) measure ORP (oxidation–reduction potential) for redox monitoring. Polymer bodies with an open junction are less prone to clogging/fouling.

ISE (ion-selective) target NH??, F-, NO?-, Cl-, Ca2+… They require ISA (ionic strength adjuster), multiple standards and a slope check.

The chloridometer electrode is dedicated to the coulometric titration of chloride (sweat tests, saline matrices). It must be instrument compatible and maintained according to the manufacturer’s protocol.

Probes for dissolved O? are available in optical (low maintenance, no electrolyte) or electrochemical (Clark/galvanic, with membrane and electrolyte) versions. Conductivity probes come as 2-pole (low-conductivity waters) or 4-pole (wide range) with cell constant K=0.1/1/10. Pt100/Pt1000 probes, thermocouples or NTCs provide a stable temperature reference.

The cable makes the difference: coaxial low noise, controlled length, connectors BNC, DIN, S7 head or multipin, RCA, 4 mm or 2 mm banana, IP67 sealing as required.

Selection criteria: nature of the sample (proteinaceous, viscous, low conductivity), required accuracy, temperature, acceptable maintenance, meter/connection compatibility.

The table below compares the main families:

Type	Principle	Applications
pH	Glass potential vs reference (ATC optional)	Water quality, biology, formulation, fermentation, etc.
Redox (ORP)	Noble metal electrode (Pt/Au) vs reference	Disinfection, oxidation, process control
ISE	Ion-selective membrane + ISA	Analytical chemistry, environment, agri-food
O? dissous	Optode or Clark cell	Cell culture, aquaculture, waters
Conductivité	2/4-pole cell, K 0.1–10	USP/Ph. Eur., salinity, CIP monitoring
Température	RTD Pt100/Pt1000 or NTC	ATC reference, temperature traceability

In which fields are electrodes and probes used?

• Life sciences/bioprocessing : control of pH, dissolved O? and conductivity in media; fermentation and cell culture monitoring.
• Pharmaceutical : USP/Ph. Eur. conductivity, raw-material pH, release testing, checks in controlled environments.
• Food & beverage : pH of cheese/meat (spear-tip probe), brines (Cl- via ISE or chloridometer), maturation/ripening, HACCP.
• Environment : water quality (pH/ORP/ O?/EC), field and laboratory.
• Cosmetics & chemicals : formulation, stability, oxidation, neutralisation.
• Clinical : chloride determination by chloridometer (sweat test).
• Education & R&D : versatility, demonstrations and prototyping.

Available electrode and probe types

FAQs about laboratory electrodes and probes

How to choose a pH electrode for challenging/dirty matrices?
Prefer double junction, open junction, a refillable electrode and a polymer body to limit clogging and ease maintenance.

ATC or no ATC: what is the difference?
ATC measures temperature and allows the meter to compensate the reading. Result: faster stabilisation and better accuracy under changing conditions.

ISE: calibration best practices?
Use at least 2–3 standards, add ISA, stir continuously, allow sufficient equilibration time, and check the slope (mV/decade) to validate the method.

Dissolved O?: optical or electrochemical?
Optical = low maintenance, no electrolyte, flow-independent. Electrochemical is robust and cost-effective but requires a membrane and electrolyte.

Which conductivity cell should I choose?
K=0.1 for ultrapure water, K=1 for drinking/process water, K=10 for high conductivities; 4-pole for a wide range and reduced polarisation.

How should I store a pH electrode?
Immerse the bulb and junction in 3 M KCl. Never store in deionised water. Clean according to the matrix and recondition if necessary.

Do cables affect the measurement?
Yes. A short, low-noise cable reduces interference. Check BNC/DIN compatibility and IP67 sealing for field use.

Is a chloridometer electrode universal?
No. These electrodes are specific to chloridometers (coulometric titration). Follow the manufacturer’s part numbers and compatible kits.