Overview
IEC 60746-2:2003 - "Expression of performance of electrochemical analyzers - Part 2: pH value" is an international standard that defines terminology, performance criteria and verification tests for pH analyzers, sensor units and electronic units used to determine the pH of aqueous solutions. This second edition (2003) is designed to be read together with IEC 60746-1:2003 and supports quality-assurance applications under ISO 9001/9002/9003 by specifying how manufacturers should state and verify pH performance.
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Key Topics
- Terminology and definitions for pH measurement components: pH sensor (e.g., glass electrode), reference electrode, temperature compensator, sensor unit and electronic unit.
- Measurement principle: pH derived from electrode e.m.f. differences and the Nernstian (theoretical) slope; practical slope and Percentage Theoretical Slope (PTS) are defined for real sensors.
- Performance statements manufacturers must declare, including uncertainties expressed in pH units.
- Verification and test procedures for:
- Zero point pH, isopotential pH and percentage theoretical slope (PTS)
- Temperature compensation and sample temperature effects
- Analyzer performance metrics: intrinsic uncertainty, linearity, repeatability, drift, warm-up time, response times and output fluctuation
- Tests for sensor units, electronic units and complete analyzers
- Reference materials and tools: use of standardized reference buffer solutions (Annex B, updated with IUPAC recommendations) and pH simulators for instrument testing.
- Influence quantities: recommended standard values and ranges for environmental and sample influence parameters that affect performance.
Applications
Who uses IEC 60746-2:2003 and why:
- Manufacturers of pH analyzers and sensor units - to specify product performance, produce datasheets and meet quality assurance requirements.
- Calibration and test laboratories - to perform repeatable verification of pH instruments against standardized procedures and buffer solutions.
- Process control engineers and QA managers in water treatment, chemical, pharmaceutical, food & beverage and environmental monitoring - to select instruments and interpret manufacturer performance claims.
- Procurement and certification bodies - to evaluate compliance with declared pH measurement performance.
Practical benefits include consistent instrument specifications, comparable test results across labs, and support for ISO-based quality systems.
Related Standards
For implementation, read IEC 60746-2 alongside IEC 60746-1 and follow the Annexes (buffer solution data, simulator specs and response-time alternatives) for accurate, traceable pH performance evaluation.