ISO 6703-3:1984 水質 — シアン化物の測定 — Part 3: 塩化シアンの測定 | 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. Every 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.

Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting.

International Standard ISO 6703/3 was prepared by Technical Committee ISO/TC 147, Water quality.

Attention is drawn to the toxicity of cyanide and to the need to take extreme care when handling cyanides and their solutions.

Carry out all operations in a fume cupboard. Avoid contact with the skin and eyes. When pipetting, always use a safety pipette (pipette by bulb). Detoxify samples and solutions containing cyanides or heavy metals in accordance with local official regulations.

Other chemicals specified in this part of ISO 6703 are also hazardous, for example pyridine.

0 Introduction

Cyanides may be present in water as hydrocyanic acid (prussic acid), as cyanide ions and as complex cyanides. They may be determined as total cyanide or as easily liberatable cyanide. If cyanide compounds are chlorinated, cyanogen chloride (CICN) is produced, and this compound has to be determined separately.

This International Standard comprises four parts as follows:

Part 1: Determination of total cyanide

Part 2: Determination of easily liberatable cyanide

Part 3: Determination of cyanogen chloride

The methods described in parts 1, 2 and 3 are suitable for controlling the quality of water and.for the examination of municipal sewage and industrial effluents. They are appropriate to the technology available for the destruction of cyanides in treatment plants, and are based on the separation of liberated hydrogen cyanide (or in the case of this part of ISO 6703, of cyanogen chloride) by stripping with a carrier gas.

The method specified in part 4 is suitable for the determination of smaller amounts of cyanide, depending on the concentrations of copper and nickel.

1 Scope and field of application

This part of ISO 6703 specifies a method for the determination of cyanides, as cyanogen chloride (see clause 2) in water.

The method is applicable for the determination of cyanogen chloride concentrations in the range 0,02 to 15 mg/l.

The ions and compounds listed in the table, if present singly or in combination at concentrations above the specified limiting concentration, interfere with the method (the list is not exhaustive).

The presence of aldehydes, e.g. formaldehyde, may give lower cyanide values because of the formation of cyanohydrin.

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