BS ISO 11262:2011

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents
6 Apparatus
7 Sample preservation and preparation
8 Direct liberation using orthophosphoric acid
9 Determination of cyanide - Photometric method
10 Determination of cyanide - Titrimetric method using
   an indicator
11 Expression of results
12 Precision
13 Test report
Annex A (informative) - Precision data
Annex B (informative) - Extraction with sodium hydroxide
        solution and subsequent liberation using
        orthophosphoric acid
Annex C (informative) - Comparison of the direct liberation
        of total cyanide and sodium hydroxide extraction
        with subsequent liberation
Bibliography

Pertains to as-received (field-moist) samples and specifies different procedures for the liberation of cyanide from the soil.

This International Standard is applicable to as-received (field-moist) samples and specifies two different procedures for the liberation of cyanide from the soil:

• direct liberation of hydrogen cyanide using orthophosphoric acid (normative);

• extraction with sodium hydroxide solution and subsequent liberation using orthophosphoric acid (informative, see AnnexB).

The liberated cyanide is determined either by a photometric method or a titrimetric method using an indicator.

The method is applicable to all types of soil.

Under the conditions specified in this International Standard, the lower limit of application is 0,5mg/kg of total cyanide (expressed on the as-received basis) for photometric determination and 10mg/kg for titrimetric determination.

NOTE Using the alkaline extraction followed by liberation using phosphoric acid, the lower limit of application is 1mg/kg of total cyanide (expressed on the as-received basis) for photometric determination and 30mg/kg for titrimetric determination.