DIN EN ISO 17380:2013-10

Cyanides may be present in soil as cyanide ions and as complex cyanides. They can be determined as easily-liberatable cyanide or as total cyanide. Complex cyanide can be calculated by subtracting the easily-liberatable cyanide result from the total cyanide result. This International Standard specifies a method for the photometric determination of the total cyanide and easily-liberatable cyanide content in soil using automated distillation/continuous-flow analysis. The International Standard applies to all types of soil with cyanide contents above 1 mg/kg on the basis of dry matter, expressed as cyanide ion. Methods using flow analysis automate wet chemical procedures and are particularly suitable for the processing of many analytes in water or soil extracts in large sample series at a high analysis frequency. The continuous flow analysis (CFA) method uses an automated dosage of the sample into a flow system (manifold) where the analytes in the sample react with the reagent solution on their way through the manifold. The sample preparation may be integrated in the manifold. The reaction product is measured in a photometric detector (for example, flow cell photometer). In ISO 11262 a manual method for the photometric and volumetric determination of total cyanide in soil samples is described. It should be noted that the total cyanide results in soil samples as described in ISO 11262 may show slight differences from this International Standard. These differences are not considered to be very significant for this analysis. The easily-liberatable cyanide test has been removed from ISO 11262 because the validation data for this method were very poor. For the analysis of cyanide in water ISO 14403 can be applied. The analytical procedure described therein is identical to the one specified in this International Standard. The committee responsible for this standard is NA 119-01-02-02 UA "Chemische und physikalische Verfahren" ("Chemical and physical methods") at the Water Practice Standards Committee (NAS) at DIN.