ASTM D5904-02(2024) PDF

Overview

ASTM D5904-02(2024) is a standard test method developed by ASTM International for determining total carbon (TC), inorganic carbon (IC), and total organic carbon (TOC) in water samples. It is applicable to water from diverse sources, including natural, domestic, and industrial environments. This method employs ultraviolet-persulfate oxidation and a CO₂-selective membrane, with measurement conducted through membrane conductivity detection. The technique is particularly valued for its high sensitivity, stability, and suitability for both laboratory analysis and online water monitoring.

Key Topics

• Measurement Range: Suitable for detecting carbon concentrations in water from 0.5 mg/L to 30 mg/L, with higher levels measurable after appropriate dilution.
• Test Principle: Organic carbon is oxidized using UV light and persulfate. The resulting CO₂ passes through a gas-permeable membrane and is measured indirectly by detecting changes in the conductivity of high-purity water.
• Separate Channels: The system uses two channels-one for total carbon measurement (TC) and one for inorganic carbon (IC). TOC is calculated as the difference between TC and IC.
• Sample Preparation: Samples must be acidified to enhance CO₂ release. For accurate measurements, especially in complex matrices, the test method recommends degassing or sparging to reduce IC levels.
• Interferences & Limitations: High chloride concentrations (>250 mg/L) and suspended or refractory materials may interfere. The particle size of samples must also be compatible with the injection system.
• Quality Assurance: Calibration verification, use of reagent blanks, and duplicate analysis are necessary to ensure precision and bias are within accepted limits.

Applications

• Water Quality Monitoring: TOC measurements are crucial for assessing the presence of organic pollutants in high-purity, drinking, and wastewater. This makes the method valuable for water utilities, regulatory compliance, and industrial process monitoring.
• Waste Treatment Evaluation: The standard is commonly used to monitor the effectiveness of wastewater treatment by quantifying reductions in organic carbon.
• Industrial Water Management: Industries such as semiconductor manufacturing, pharmaceuticals, and power generation utilize TOC/IC/TC analyses to maintain water purity and ensure product quality.
• Environmental Assessments: The method provides data for understanding carbon cycling and pollution levels in natural waters, supporting environmental protection and remediation efforts.
• Online Monitoring: Its capability for continuous, online measurement allows for real-time process control and immediate detection of contamination events.

Related Standards

• ASTM D1129 – Terminology Related to Water
• ASTM D1193 – Specification for Reagent Water
• ASTM D2777 – Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
• ASTM D3370 – Practices for Sampling Water from Flowing Process Streams
• ASTM D5810 – Guide for Spiking into Aqueous Samples
• ASTM D5847 – Practice for Writing Quality Control Specifications for Water Analysis

Practical Value

This ASTM D5904-02(2024) standard provides a reliable, sensitive, and adaptable method for carbon analysis in water. Its high sensitivity and robust interference control support accurate monitoring of trace-level carbon, essential for regulatory compliance, public health protection, and process optimization. Laboratories and facilities seeking high confidence in their water quality data will benefit from implementing this standardized methodology for TOC, TC, and IC detection in diverse water matrices.