ISO 7875-1:1996 水質 — 界面活性剤の測定 — Part 1: メチレンブルー指数（MBAS）の測定による陰イオン性界面活性剤の測定 | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

International Standard ISO 7875-1 was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical, biochemical methods.

This second edition cancels and replaces the first edition (ISO 7875-1:1984, of which it constitutes a technical revision.

ISO 7875 consists of the following parts, under the general title Water quality — Determination of surfactants:

• Part 1: Determination of anionic surfactants by measurement of the methylene blue index (MBAS)
• Part 2: Determination of non-ionic surfactants using Dragendorff reagent

Introduction

Natural and synthetic anionic surface-active substances may be determined as methylene-blue active substances (MBAS); they are referred to as MBAS index, a summary parameter.

1 Scope

This part of ISO 7875 specifies a spectrometric method for the determination of anionic surfactants by measurement of the methylene blue index (MBAS) in aqueous media.

The method is applicable to drinking water, surface water as well as waste water, for example for the determination of the primary degradation of surfactants under investigation in test systems containing natural or synthetic waste water. It applies for both laboratory scale and technical waste-water treatment plants.

In the case of effluents originating from municipal waste-water treatment plants, the MBAS index comprises not only synthetic but also, to a considerable extent, natural anionic surface active substances

This method is applicable to a range of concentrations from 0,1 mg/l to 5,0 mg/l and the limit of detection is about 0,05 mg/l for solutions of standard surfactants in distilled water.

Under the experimental conditions, sulfonates and sulfates are the compounds chiefly measured, but some positive and negative interferences may occur (see clause 9).

2 Normative references

The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 7875. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 7875 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.