DIN EN ISO 9562 Water Quality – Determination of Adsorbable Organically Bound Halogens (AOX)

The international DIN EN ISO 9562 standard describes a method for determining the mass concentration of organically bound halogens adsorbed on activated carbon (AOX). It applies to samples with concentrations of up to 10 µg/L. The level of these adsorbable organically bound halogens, also known as adsorbable organic halides, measures the sum of halogenated hydrocarbons that contain chlorine, bromine and iodine and which can, under exactly specified conditions, be adsorbed by activated carbon. The AOX sum parameter does not contain any information on fluorine, as the coulometric detection used here cannot measure it. Other methods such as DIN 38409-59 have become established for the determination of organically bound fluorine compounds.

The DIN EN ISO 9562 standard specifically describes a method for water. It is suitable for samples with less than 1 g/L of inorganically bound chloride. For all samples with higher concentrations, dilution is required prior to enrichment. Alternatively, separation of the inorganic chlorine compounds by solid phase extraction (SPE) is possible as a modification of the method (SPE-AOX). 

In terms of its content, the standard explains the fundamentals of the process, in which the column method, shaking method, and the stirring method are acceptable methods for adsorbing the organic halogen compounds contained in the sample. The standard then addresses the reagents used in detail – including water, activated carbon, nitric acid and sulfuric acid – each with their respective characteristics. Additionally, it describes the setup of the method along with technical specifications for the devices used for AOX enrichment and analysis, plus the methods for sample adsorption, experimental procedure, and calculation steps to determine the mass concentrations. 

Organic halogen compounds are usually synthetic chemicals, released primarily by industrial processes and domestic households. They are found, for example, in cleaning agents, coolants, disinfectants and solvents. If these compounds enter soil and groundwater, they are taken up by plants, animals and people, where they realize their toxic and cell-damaging effects. To prevent this and estimate the existing hazard level, stringent monitoring is required. AOX is an important convention parameter in water quality monitoring. It allows a statement to be made about water quality and is also used to monitor the contamination of sewage sludge and soil samples.

The analytic method described in DIN EN ISO 9562 is used, for example, in the analysis of industrial wastewater and surface water for environmental monitoring purposes, in water treatment, as well as in testing of industrial wastewater (e.g., for direct dischargers). 

With the multi X 2500, Analytik Jena offers a powerful system for sum parameter analysis that meets the requirements of the DIN EN ISO 9562 standard. The analyzer is a compelling option thanks to its high sample throughput and precise measurement while keeping operating costs low. 

Sources

• Norm DIN EN ISO 9562 – Wasserbeschaffenheit – Bestimmung adsorbierbarer organisch gebundener Halogene (AOX)
• Organisch gebundene Halogenverbindungen schnell bestimmen (vogel.de)
• Fundamentals – Instrumentation and Techniques of Halogen Analysis (Analytik Jena)