ASTM D2791-19 PDF

Full title and description

ASTM D2791-19 — Standard Test Method for On-Line Determination of Sodium in Water. This standard specifies procedures for continuous (on-line) measurement of trace sodium in water using a sodium ion-selective electrode, intended for monitoring purity and detecting contamination in process and high-purity water systems.

Abstract

Provides a procedure for on-line determination of sodium at trace concentrations (parts per billion/µg·L−1) using an ion‑selective electrode. The method is applicable across a wide concentration range and is intended for monitoring make‑up water, condensate, feedwater, boiler water, and other streams where low-level sodium is critical to system performance and materials integrity. The standard notes the absence of extensive collaborative precision/bias data and emphasizes reagent purity and appropriate system calibration.

General information

• Status: Current (designation D2791-19; replaces earlier editions).
• Publication date: Approved December 15, 2019; published January 2020 (D2791‑19).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 13.060.50 — Examination of water for chemical substances / Water analysis.
• Edition / version: D2791‑19 (current edition, 2019).
• Number of pages: 7 pages.

Scope

This test method covers on-line determination of trace sodium in water using a sodium ion‑selective electrode. It is generally applicable over a wide range (reported applicability roughly from about 0.01–0.05 up to 10 000 µg/L depending on technique and electrode), and is intended for monitoring contamination, breakthrough of deionization equipment, and performance of condensate polishers, boiler feedwater systems, and other high‑purity water streams. The standard also highlights requirements for reagent purity and notes that collaborative precision/bias data are not provided within the document.

Key topics and requirements

• On‑line use of a sodium ion‑selective electrode as the measurement technique.
• Applicable measurement range spanning trace (µg·L−1 / ppb) to higher concentrations (up to ~10 000 µg·L−1) depending on electrode and setup.
• Emphasis on reagent and materials of suitable purity to avoid sodium contamination of ultra‑low sodium samples.
• Calibration, temperature and flow control, and sample conditioning practices for stable on‑line measurements.
• Notes on precision and bias: the standard states adequate collaborative data for precision/bias are not provided and users should consider interlaboratory verification where needed.
• Safety and laboratory practice reminders appropriate to chemical and on‑line monitoring systems.

Typical use and users

Used by water‑analysis laboratories, power generation and industrial water treatment engineers, plant analytical technicians, instrument manufacturers and calibration/service providers, and quality/acceptance testing groups that require continuous monitoring of sodium in feedwater, condensate, boiler water, ultrapure water systems, and related process streams. The method is also of interest to consultants and researchers involved in water chemistry control and corrosion prevention.

Related standards

Referenced and related ASTM standards commonly cited in D2791 include terminology and sampling practices such as D1129 (terminology relating to water), D1193 (reagent water), D2777 (precision and bias practice), D3864 (guide for on‑line monitoring systems for water analysis), D3370 (sampling flowing process streams), and D5540 (practices for flow/temperature control). D2791 is maintained under ASTM Committee D19 on Water and replaces earlier D2791 editions (for example D2791‑13).

Keywords

sodium; ion‑selective electrode; on‑line monitoring; trace analysis; water analysis; boiler feedwater; condensate; deionization breakthrough; ppm; ppb; water quality.

FAQ

Q: What is this standard?

A: ASTM D2791‑19 is a standard test method that describes an on‑line procedure using a sodium ion‑selective electrode for determining trace amounts of sodium in water streams.

Q: What does it cover?

A: It covers the on‑line measurement technique, recommended practices for calibration and sample handling, typical applicable concentration ranges (trace µg·L−1 up to ~10 000 µg·L−1), and the contexts in which the method is applied (e.g., monitoring make‑up water, condensate, boiler feedwater). The standard notes that users should be aware that comprehensive collaborative precision/bias data are not provided.

Q: Who typically uses it?

A: Analytical laboratories, power and process plant water chemists, maintenance and instrumentation teams, equipment manufacturers, and consultants who need continuous sodium monitoring in clean and process waters.

Q: Is it current or superseded?

A: The D2791‑19 edition (approved Dec 15, 2019; published early 2020) is the current edition that superseded earlier versions such as D2791‑13. Users should check ASTM for any later revisions.

Q: Is it part of a series?

A: It is part of ASTM Committee D19’s water analysis collection and connects to practices and guides for sampling, on‑line monitoring systems, and precision/bias practices (see referenced ASTM documents listed in the Related standards section).

Q: What are the key keywords?

A: Sodium, ion‑selective electrode, on‑line determination, trace analysis, water quality, boiler water, condensate, deionization monitoring.