ISO 10523-2008 PDF

Full title and description

ISO 10523:2008 — Water quality — Determination of pH. This International Standard specifies an electrochemical method (using a pH‑meter and suitable electrodes) for determining the pH value of a wide range of waters and liquid sludges, including rain, drinking and mineral waters, bathing waters, surface and ground waters, and municipal and industrial waste waters.

Abstract

ISO 10523:2008 defines procedures and requirements for pH measurement in aqueous matrices over the range pH 2 to pH 12, for samples with ionic strength below I = 0.3 mol/kg (approx. conductivity < 2000 mS/m at 25 °C), and for measurement temperatures between 0 °C and 50 °C. It covers instrument resolution, electrode performance, calibration, sample handling and common interferences.

General information

• Status: Published (International Standard, confirmed in periodic reviews).
• Publication date: 2008 (Edition 2, published December 2008).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 13.060.50 (Examination of water for chemical substances).
• Edition / version: Edition 2 (2008).
• Number of pages: 13 pages (official ISO publication pagination).

Scope

Provides a standardized electrochemical procedure for reporting pH of aqueous samples. The standard is applicable to rain, potable and mineral waters, bathing waters, surface and groundwater, municipal and industrial wastewaters and liquid sludges when the sample ionic strength and temperature fall within the specified limits; it also addresses calibration, electrode selection and maintenance, resolution and measurement practice to reduce interferences and improve reproducibility.

Key topics and requirements

• Principle: measurement of the potential difference of an electrochemical cell with a pH‑meter and temperature compensation.
• Applicable sample types: rain, drinking/mineral, bathing, surface and ground waters, municipal and industrial waste waters, and liquid sludge.
• Measurement ranges and limits: pH 2 to pH 12; ionic strength I < 0.3 mol/kg (conductivity approx. < 2000 mS/m at 25 °C); temperature 0 °C to 50 °C.
• Instrument and electrode requirements: meter resolution 0.01 pH or better; electrode practical slope ≥95% of theoretical; reference electrode flow‑rate and maintenance guidance.
• Calibration and reporting: use appropriate buffer solutions, indicate measurement temperature with pH results, and report any deviations or interferences.
• Sample handling and interferences: guidance on minimizing CO2 exchange, degassing, electrode fouling, and measuring after settling for turbid/suspended samples.

Typical use and users

Used by environmental and water testing laboratories, water and wastewater utilities, regulatory agencies, research institutions and instrument manufacturers/field technicians for routine monitoring, compliance testing, process control and inter‑laboratory comparability of pH results. The standard supports laboratory quality systems and harmonised reporting of water pH.

Related standards

Commonly referenced companion standards include parts of the ISO 5667 series on water sampling (sampling, preservation and handling), ISO 3696 (water for analytical laboratory use), ISO 4796‑2 (laboratory bottles) and other ISO/EN methods for complementary water quality parameters (e.g., conductivity, alkalinity). ISO 10523:1994 is the withdrawn predecessor; ISO 10523:2008 supersedes that edition.

Keywords

pH; water quality; pH meter; pH electrode; calibration; buffer solutions; ionic strength; sample handling; temperature compensation; ISO 10523.

FAQ

Q: What is this standard?

A: ISO 10523:2008 is an International Standard that specifies an electrochemical method for determining the pH of various types of water and liquid sludge.

Q: What does it cover?

A: It covers measurement principle, instrument and electrode requirements, calibration and reporting, recommended resolution, acceptable pH and temperature ranges, ionic strength limits, handling of interferences and practical guidance for obtaining reproducible pH values.

Q: Who typically uses it?

A: Environmental and analytical laboratories, water and wastewater utilities, regulators, researchers and instrument manufacturers use this standard for routine monitoring, compliance testing and to ensure comparability of pH data.

Q: Is it current or superseded?

A: ISO 10523:2008 is the current edition published in 2008 and has been confirmed in ISO periodic reviews; it supersedes ISO 10523:1994 (withdrawn). Users should check the ISO catalogue for any subsequent amendments or a newer revision.

Q: Is it part of a series?

A: While ISO 10523 itself is a standalone method for pH, it is commonly used alongside related ISO series such as ISO 5667 (water sampling), ISO 3696 (laboratory water) and other water‑quality test standards to form a complete sampling and analysis workflow.

Q: What are the key keywords?

A: pH, pH measurement, pH electrode, buffer, calibration, water quality, ionic strength, sampling, temperature compensation, ISO 10523.