ASTM E70-24 PDF

Full title and description

St ASTM E70-24 — Standard Test Method for pH of Aqueous Solutions With the Glass Electrode. This ASTM test method specifies the apparatus, electrode systems, calibration and measurement procedures for determining the pH of aqueous solutions using a glass electrode and an appropriate pH meter.

Abstract

ASTM E70-24 provides a standardized electrometric procedure for measuring pH with a glass electrode. It defines required equipment (glass and reference electrodes, meter, temperature compensation), calibration using standard buffer solutions, measurement technique, electrode care, precision considerations and reporting conventions. The document is intended to ensure reproducible pH determinations of aqueous solutions within the method’s applicability limits.

General information

• Status: Active (current edition)
• Publication date: January 1, 2024
• Publisher: ASTM International
• ICS / categories: 71.040.50 (Physicochemical methods of analysis)
• Edition / version: E70-24 (2024 revision)
• Number of pages: 6

Scope

This test method specifies apparatus and procedures for the electrometric measurement of pH values of aqueous solutions with the glass electrode. It addresses electrode systems, calibration with standard buffer solutions, temperature effects and good measurement practice. The standard does not prescribe how solutions are prepared; it is intended for aqueous matrices where the glass-electrode technique is applicable (practical accuracy typically within the limits described in the standard — e.g., roughly pH 2 to 12 and under moderate ionic-strength conditions).

Key topics and requirements

• Apparatus and electrode types: glass measuring electrode, suitable reference electrode and pH meter specifications.
• Calibration procedures: use of traceable standard buffer solutions, one- and two- (or multi-) point calibrations and temperature adjustment.
• Temperature compensation: requirements and correct handling of temperature effects on electrode and buffers.
• Measurement procedure: sample handling, immersion technique, stabilization criteria and reading conventions.
• Electrode maintenance and conditioning: cleaning, storage, and checks for electrode performance and drift.
• Precision, bias and uncertainty: guidance on repeatability, reproducibility and how to report measurement uncertainty.
• Reporting requirements: required information to include with results (method designation, electrode type, calibration details, temperature, and any deviations).

Typical use and users

Used by analytical and quality-control laboratories, environmental testing facilities, water and wastewater treatment plants, pharmaceutical and food industry QC, process control engineers, instrument manufacturers and academic researchers. Typical applications include routine pH monitoring, method validation, instrument commissioning and interlaboratory comparisons where a standardized electrometric technique is required.

Related standards

ASTM E70-19 (previous edition, now superseded), ISO 10523 (pH — determination of pH of aqueous solutions), EPA Method 150.1 (electrometric pH determination), ASTM D1293 (pH of water), and other regional or industry-specific pH measurement methods and guidance documents.

Keywords

pH, glass electrode, pH meter, electrometric measurement, calibration, buffer solution, reference electrode, temperature compensation, measurement uncertainty, electrode maintenance.

FAQ

Q: What is this standard?

A: ASTM E70-24 is the ASTM International Standard Test Method for pH of Aqueous Solutions With the Glass Electrode, defining how to perform electrometric pH measurements using a glass electrode system.

Q: What does it cover?

A: It covers required apparatus, electrode and meter considerations, calibration with standard buffers, temperature compensation, measurement technique, electrode maintenance, precision/uncertainty considerations and reporting of results. It does not prescribe sample preparation.

Q: Who typically uses it?

A: Analytical laboratories, environmental and water-treatment facilities, pharmaceutical and food QC, instrument manufacturers, process engineers and researchers who need a standardized pH measurement procedure.

Q: Is it current or superseded?

A: The current edition is E70-24, approved January 1, 2024. It supersedes the previous edition E70-19. (Status current as of February 21, 2026.)

Q: Is it part of a series?

A: E70 is a standalone test method within the ASTM series of instrumental and chemical test methods; it is maintained under ASTM Committee D16 (Aromatic, Industrial, Specialty and Related Chemicals) and the subcommittee responsible for instrumental analysis. Related ASTM, ISO and EPA methods address pH in specific matrices or contexts.

Q: What are the key keywords?

A: pH, glass electrode, pH meter, buffer calibration, electrometric measurement, temperature compensation, electrode maintenance, measurement uncertainty.