EN ISO 16265:2012

Foreword
Introduction
1 Scope
2 Normative references
3 Interferences
4 Principle
5 Reagents
6 Apparatus
7 Sampling and sample pretreatment
8 Procedure
9 Calculation of the results
10 Expression of results
11 Precision
12 Test report
Annex A (informative) - Example of a flow diagram for the
        determination of MBAS index by continuous flow
        analysis (CFA)
Annex B (informative) - Precision data
Bibliography

ISO 16265:2009 specifies a procedure for the determination of the methylene blue active substances (MBAS) index, in the ranges 0,05 mg/l to 0,5 mg/l and 0,5 mg/l to 5,0 mg/l, in various water samples (e.g. ground water, drinking water, surface water, waste water and leachates). Anionic surfactants are the most important substances showing methylene blue activity. This method is therefore useful for estimating the anionic surfactant content [including anionic surfactants with carboxylate groups (e.g. soaps)] of water. Other types of substance may also show methylene blue activity and contribute to the result. On a case-by-case basis, the range of the analysis may be changed and the method used for other concentration ranges provided they cover exactly one decade of concentration units.