ISO 22066:2020

INTERNATIONAL ISO
STANDARD 22066
First edition
2020-09
Water quality — Determination
of total cyanide — Method using
segmented flow injection, in-line
ultraviolet digestion analysis by gas
diffusion and amperometric detection
Qualité de l'eau — Dosage du cyanure total — Méthode utilisant
l'injection en flux segmenté, l'analyse par digestion UV continue par
diffusion de gaz et la détection ampérométrique
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Principle . 2
5 Interferences . 2
5.1 Interferences by oxidizing agents . 2
5.2 Interferences by sulfide . 2
6 Reagents . 3
7 Apparatus . 6
8 Sampling and sample preparation . 7
8.1 Oxidizing agent . 7
8.2 Sulfide removal . 7
8.3 Preservation . 8
9 Procedure. 8
9.1 Flow system set up . 8
9.2 Reagent blank measurement . 8
9.3 Checking the suitability of the segmented flow analysis system . 9
9.3.1 Cyanide electrode stabilization . 9
9.3.2 Performance verification of the system . 9
9.4 Calibration . 9
9.5 Sample measurement .10
9.5.1 Cyanide measurement.10
10 Calculations.10
11 Expression of results .10
12 Test report .10
Annex A (informative) Example of a segmented flow analysis system .12
Annex B (normative) Determination of the real cyanide concentration in the potassium
cyanide solution (6.5.1) or potassium tetracyanozincate solution (6.6.1) .13
Annex C (informative) Performance data .14
Bibliography .15
Foreword
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This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2,
Physical, chemical and biochemical methods.
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iv © ISO 2020 – All rights reserved

Introduction
Methods using flow analysis automated wet chemical procedures are particularly suitable for the
determination of many analytes in water in large sample series at a high analysis frequency.
Analyses can be performed by segmented flow injection analysis (SFIA) using the feature of an automatic
dosage of the sample into a flow system (manifold) where the analyte in the sample is digested with
ultraviolet radiation at 312 nm and the reagent solutions on its way through the manifold. The reaction
product is measured by a flow detector (for example amperometer).
Speciation of cyanide species can be inferred by comparing free cyanide in accordance with
ISO 17690:2015, available weak and dissociable cyanide in accordance with ISO 20950-1, and total
cyanide using this method.
INTERNATIONAL STANDARD ISO 22066:2020(E)
Water quality — Determination of total cyanide —
Method using segmented flow injection, in-line ultraviolet
digestion analysis by gas diffusion and amperometric
detection
IMPORTANT NOTE — − The performance of this method has been established for a range of
sample matrices, which are reported in ANNEX C. These matrices represent environmental,
mining influenced and metallurgical process samples. This method is therefore recommended
for mining impacted samples. Caution is recommended for the application of alternative ISO
methods to mining influenced and metallurgical process samples if those matrices are not
explicitly mentioned in the scope; as potential biases and interferences typical for them have
not been sufficiently investigated and may not be properly mitigated.
WARNING — Persons using this document should be familiar with normal laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure neutralization and proper disposal of waste solutions.
IMPORTANT — It is absolutely essential that tests conducted in accordance with this document
be carried out by suitably qualified staff.
1 Scope
This document specifies operationally defined methods for the determination of total cyanide in
various types of water such as drinking water, ground water, surface water, wastewaters, metallurgical
processing tailings reclaim solution, heap leach barren solution, mill slurry tailings filtrate and leaching
solutions, with cyanide concentrations from 5 µg/l to 2 000 mg/l expressed as cyanide ions in the
undiluted sample. The range of application can be extended by reducing the sensitivity (Figure A.1.).
NOTE ISO 2080:2008, 3.105, defines free cyanide. The concentration of total cyanide as defined in
ISO 2080:2008, 3.191 includes free cyanide, cyanide complexed with metals in solution as cyanide anion, but not
necessarily all of the metal cyanide complexes present as determined by a specified analytical method.
In this method, six suitable mass concentration ranges from 5 µg/l to 50 µg/l, from 50 µg/l to 500 µg/l,
from 0,5 mg/l to 5 mg/l, from 5 mg/l to 50 mg/l, from 50 mg/l to 500 mg/l and from 500 mg/l to
2 000 mg/l are described.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 8466-1, Water quality — Calibration and evaluation of analytical methods and estimation of
performance characteristics — Part 1: Statistical evaluation of the linear calibration function
ISO 8466-2, Water quality — Calibration and evaluation of analytical methods and estimation of
performance characteristics — Part 2: Calibration strategy for non-linear second-order calibration
functions
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
total cyanide
sum of HCN, cyanide ions and cyanide bound in the metal-cyano complexes that are dissociated, using
digestion in the presence of ultraviolet (UV) radiation at 312 nm and sulfuric acid into HCN/CN⎺ in
accordance with this document
4 Principle
In the analytical procedure employed for
...