SIST EN ISO 17380:2013
(Main)Soil quality - Determination of total cyanide and easily liberatable cyanide - Continuous-flow analysis method (ISO 17380:2013)
Soil quality - Determination of total cyanide and easily liberatable cyanide - Continuous-flow analysis method (ISO 17380:2013)
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.
Bodenbeschaffenheit - Bestimmung des Gehalts an gesamtem Cyanid und leicht freisetzbarem Cyanid - Verfahren mittels kontinuierlicher Durchflußanalyse (ISO 17380:2013)
Diese Internationale Norm legt ein Verfahren fest für die photometrische Bestimmung des Massenanteils an Gesamtcyanid und leicht freisetzbarem Cyanid im Boden unter Anwendung der automatisierten kontinuierlichen Destillations-Durchflussanalyse.
Diese Internationale Norm ist auf alle Bodenarten anwendbar, die einen Cyanidmassenanteil über 1 mg/kg, bezogen auf die Trockenmasse, ausgedrückt als Cyanidion, aufweisen.
ANMERKUNG Sulfidkonzentrationen in der Probe größer als 40 mg/kg Trockenmasse verursachen Störungen. Dieser Effekt zeigt sich in gespaltenen Peaks und einem langsamen Abnehmen des Detektorsignals und kann nur durch Verdünnen des Probenextrakts verhindert werden.
Qualité du sol - Détermination des cyanures totaux et des cyanures aisément libérables - Méthode d'analyse en flux continu (ISO 17380:2013)
L'ISO 17380:2013 définit une méthode de dosage photométrique de la concentration en cyanures totaux et en cyanures aisément libérables dans le sol par analyse en flux continu et distillation automatisée.
L'ISO 17380:2013 s'applique à tous les types de sols dont la concentration en cyanures, exprimée en ions cyanure, est supérieure à 1 mg/kg de matière sèche.
Kakovost tal - Določevanje celotnega cianida in lahko sprostljivega cianida - Metoda kontinuirane pretočne analize (ISO 17380:2013)
Ta mednarodni standard določa metodo za fotometrično določevanje vsebnosti celotnega cianida in lahko sprostljivega cianida v tleh s samodejno destilacijsko/kontinuirano pretočno analizo. Mednarodni standard se uporablja za vse vrste tal z vsebnostjo cianida, večjo od 1 mg/kg na podlagi suhe snovi, ki je izražena s cianidnim ionom.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 17380:2013
01-oktober-2013
.DNRYRVWWDO'RORþHYDQMHFHORWQHJDFLDQLGDLQODKNRVSURVWOMLYHJDFLDQLGD
0HWRGDNRQWLQXLUDQHSUHWRþQHDQDOL]H ,62
Soil quality - Determination of total cyanide and easily liberatable cyanide - Continuous-
flow analysis method (ISO 17380:2013)
Bodenbeschaffenheit - Bestimmung des Gehalts an gesamtem Cyanid und leicht
freisetzbarem Cyanid - Verfahren mittels kontinuierlicher Durchflußanalyse (ISO
17380:2013)
Qualité du sol - Détermination des cyanures totaux et des cyanures aisément libérables -
Méthode d'analyse en flux continu (ISO 17380:2013)
Ta slovenski standard je istoveten z: EN ISO 17380:2013
ICS:
13.080.10 .HPLMVNH]QDþLOQRVWLWDO Chemical characteristics of
soils
SIST EN ISO 17380:2013 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 17380:2013
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SIST EN ISO 17380:2013
EUROPEAN STANDARD
EN ISO 17380
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2013
ICS 13.080.10
English Version
Soil quality - Determination of total cyanide and easily liberatable
cyanide - Continuous-flow analysis method (ISO 17380:2013)
Qualité du sol - Détermination des cyanures totaux et des Bodenbeschaffenheit - Bestimmung des Gehalts an
cyanures aisément libérables - Méthode d'analyse en flux gesamtem Cyanid und leicht freisetzbarem Cyanid -
continu (ISO 17380:2013) Verfahren mittels kontinuierlicher Durchflußanalyse (ISO
17380:2013)
This European Standard was approved by CEN on 8 June 2013.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17380:2013: E
worldwide for CEN national Members.
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SIST EN ISO 17380:2013
EN ISO 17380:2013 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 17380:2013
EN ISO 17380:2013 (E)
Foreword
This document (EN ISO 17380:2013) has been prepared by Technical Committee ISO/TC 190 “Soil quality” in
collaboration with Technical Committee CEN/TC 345 “Characterization of soils” the secretariat of which is held
by NEN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by December 2013, and conflicting national standards shall be withdrawn
at the latest by December 2013.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 17380:2013 has been approved by CEN as EN ISO 17380:2013 without any modification.
3
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SIST EN ISO 17380:2013
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SIST EN ISO 17380:2013
INTERNATIONAL ISO
STANDARD 17380
Second edition
2013-06-15
Soil quality — Determination of
total cyanide and easily liberatable
cyanide — Continuous-flow analysis
method
Qualité du sol — Détermination des cyanures totaux et des cyanures
aisément libérables — Méthode d’analyse en flux continu
Reference number
ISO 17380:2013(E)
©
ISO 2013
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SIST EN ISO 17380:2013
ISO 17380:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
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Published in Switzerland
ii © ISO 2013 – All rights reserved
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SIST EN ISO 17380:2013
ISO 17380:2013(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
4.1 Pretreatment of soil samples . 2
4.2 Determination of total cyanide content . 2
4.3 Determination of easily-liberatable cyanide content . 2
5 Reagents . 2
5.1 General reagents . 2
5.2 Reagents for determination of cyanide . 3
5.3 Standard solutions for cyanide determination . 4
6 Apparatus . 6
6.1 Standard laboratory glassware and laboratory equipment . 6
6.2 Continuous flow analysis system . 6
6.3 Shaking machine. 7
7 Sampling, sample preparation and extraction . 8
8 Working range. 8
9 Procedure. 8
9.1 General . 8
9.2 Checking analysis system for correct function . 8
9.3 Calibration graph . 9
9.4 Measurement of samples . 9
9.5 Cleaning of the analysis system .10
10 Calculation of the cyanide content in the sample .10
11 Precision .10
12 Test report .11
Annex A (informative) Recovery and repeatability .12
Annex B (informative) Information on continuous flow automatic distillation apparatus .14
Annex C (informative) Alternative distillation buffer (pH = 3,8) .15
Bibliography .16
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SIST EN ISO 17380:2013
ISO 17380:2013(E)
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 17380 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3, Chemical
methods and soil characteristics.
This second edition cancels and replaces the first edition (ISO 17380:2004), which has been
technically revised.
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SIST EN ISO 17380:2013
ISO 17380:2013(E)
Introduction
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 the
determination of easily-liberatable cyanide, complex cyanides and total cyanide.
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
[1] [2]
in a photometric detector (e.g. 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.
[6] [7]
For the analysis of cyanide in water ISO 14403-1 and ISO 14403-2 can be applied. The analytical
[7]
procedure described in ISO 14403-2 is identical to the one specified in this International Standard.
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SIST EN ISO 17380:2013
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SIST EN ISO 17380:2013
INTERNATIONAL STANDARD ISO 17380:2013(E)
Soil quality — Determination of total cyanide and easily
liberatable cyanide — Continuous-flow analysis method
WARNING — Cyanide solutions are highly toxic. Appropriate measures shall be taken to avoid
ingestion. Care should be taken in the disposal of these solutions.
1 Scope
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.
NOTE Sulfide concentrations in the sample higher than 40 mg/kg dry matter cause interference. This effect
can be recognized by the split peaks and as a slow decrease of the detector signal and can only be prevented by
diluting the sample extract.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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 9297,Water quality — Determination of chloride — Silver nitrate titration with chromate indicator
(Mohr’s method)
ISO 11262, Soil quality — Determination of total cyanide
ISO 11465, Soil quality — Determination of dry matter and water content on a mass basis — Gravimetric method
ISO 14507:2003, Soil quality — Pretreatment of samples for determination of organic contaminants
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
total cyanide content
content of inorganic cyanide compounds consisting of the sum of the contents of easily-liberatable
cyanide species and cyanide bound to metal cyanides, with the exception of thiocyanate ions and only
partial breakdown of the cyanide bound in cobalt, gold, palladium and platinum cyanide complexes
3.2
easily-liberatable cyanide
content of inorganic cyanide compounds consisting of the sum of the contents of the easily-liberatable
cyanide ions and the cyanide bound in simple metal cyanides (all expressed as CN) which are determined
under the conditions of the method described in this International Standard
Note 1 to entry: The weakly complexed cyanide contained in tetracyanonickelate(II) and dicyanomercurate(II)
is determined with the method for easily-liberatable cyanide. Up to 5 % of the strongly complexed cyanide in
iron(III) hexacyanoferrate(II), hexacyanoferrate(III) and hexocyanoferrate(II) is determined with the method
for easily-liberatable cyanide. Organic cyanide compounds (such as acetonitrile) are not determined.
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SIST EN ISO 17380:2013
ISO 17380:2013(E)
Note 2 to entry: In connection with waste from the production of gold, “easily liberatable cyanide” is named “weak
[8]
acid dissociable cyanide” .
3.3
complex cyanide content
total cyanide content less than the easily-liberatable cyanide content
4 Principle
4.1 Pretreatment of soil samples
The soil sample is extracted with 2,5 mol/l sodium hydroxide solution for 16 h. The extract is diluted
100 times, after which analysis of total and/or easily-liberatable cyanide is performed.
4.2 Determination of total cyanide content
Complex bound cyanide, present in the diluted extract (0,025 mol/l NaOH), is decomposed in a
continuously flowing stream after addition of a buffer solution, with an initial pH of 3,8, by the effect of
UV light. An UV-B lamp and decomposition coil of borosilicate glass are used. UV light with a wavelength
of less than 290 nm is absorbed by the glass, preventing the photolytic conversion of thiocyanate into
cyanide. The hydrogen cyanide present at these conditions is separated by in-line distillation at a heating
bath temperature of 125 °C ± 2 °C and then determined photometrically. The photometric determination
is based on the reaction of cyanide with chloramine-T resulting in the formation of cyanogen chloride.
This reacts with pyridine-4-carboxylic acid and 1,3-dimethylbarbituric acid to give a purple colour. The
absorbance at 606 nm is then measured to determine the cyanide content. When an interference filter is
used, a peak wavelength of 600 nm ± 10 nm can be used.
NOTE Addition of the buffer solution, with an initial pH of 3,8 (5.2.1), to the sample flow containing 0,025 mol/l
NaOH (ratio 1,0 sample : 0,42 buffer) leads to a final pH of 4,0. Varying the pH of the distillation between 3,8 and
5,7 leads to very small fluctuations in the recovery of hydrogen cyanide (only a few percent).
4.3 Determination of easily-liberatable cyanide content
Before distillation, and without UV decomposition, a zinc sulfate solution is added to the sample flow,
such that any complex iron cyanide(s) present are precipitated as zinc-cyanoferrate complexes. The
hydrogen cyanide present during these conditions is separated by distillation at a temperature of 125 °C
and photometrically determined as described under 4.2.
NOTE The added zinc sulfate replaces a water reagent (see Table 1) used in the determination of total
cyanide content.
5 Reagents
Only use reagents of recognized analytical grade and demineralized water or distilled water according
to ISO 3696, Grade 1 or 2.
5.1 General reagents
5.1.1 Hydrochloric acid w(HCl) = 37 %.
5.1.2 Hydrochloric acid c(HCl) = 1 mol/l.
Dilute 83 ml of hydrochloric acid (5.1.1) with water to 1 000 ml.
5.1.3 Hydrochloric acid c(HCl) = 0,1 mol/l.
Dilute 100 ml of 1 mol/l hydrochloric acid (5.1.2) with water to 1 000 ml.
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SIST EN ISO 17380:2013
ISO 17380:2013(E)
5.1.4 Sodium hydroxide solution c(NaOH) = 2,5 mol/l.
Dissolve 100 g of NaOH in water and dilute with water to 1 000 ml. Store in a polyethylene bottle.
5.1.5 Sodium hydroxide solution c(NaOH) = 1 mol/l.
Dissolve 40 g of NaOH in water and dilute with water to 1 000 ml. Store in a polyethylene bottle.
5.1.6 Sodium hydroxide solution c(NaOH) = 0,025 mol/l.
Dilute 25 ml of 1 mol/l sodium hydroxide (5.1.5) with water to 1 000 ml.
5.1.7 Detergent solution, polyoxyethylenelaurylether C H (OCH CH ) OH, n ≈ 23.
12 25 2 2 n
Dissolve 30 g of polyoxyethylenelaurylether by adding small quantities to 100 ml water and mix thoroughly.
NOTE This solution is commercially available as Brij-35. This information is given for the convenience of
users of this document and does not constitute an endorsement by ISO of this product. To dissolve the Brij-35, the
temperature can be raised to 40 °C.
5.1.8 Indicator solution
Dissolve 0,02 g of p-dimethylaminobenzylindenerhodanine in 100 ml acetone. This solution can be
stored for at least one week if kept in the dark and refrigerated (5 ± 3) °C.
5.1.9 Silver nitrate solution, c(AgNO ) = 0,01 mol/l
3
Dissolve 1,689 7 g of silver nitrate in approximately 400 ml water and dilute to 1 litre in a volumetric
flask with water. Check the actual concentration of the 0,01 mol/l silver nitrate by titration with sodium
chloride according to ISO 9297 on a two weekly basis. Store this solution in the dark in a brown glass
bottle. Prepare a fresh solution monthly.
5.1.10 Silver nitrate solution, c(AgNO ) = 0,001 mol/l
3
Prepare daily from 0,01 mol/l silver nitrate (5.1.9). Add 25,00 ml of 0,01 mol/l silver nitrate to a 250 ml
volumetric flask and dilute to 250 ml with water. Store this solution in the dark in a brown glass bottle.
5.1.11 20 % V/V Denatured ethanol
Mix 100 ml denatured ethanol with 400 ml water. This solution is stable for at least one year.
5.2 Reagents for determination of cyanide
5.2.1 Distillation buffer (pH = 3,8)
Dissolve 50 g of citric acid, C H O ∙ H O in 200 ml water. Add 120 ml sodium hydroxide solution 1 mol/l
6 8 7 2
(5.1.5) and if necessary adjust the pH to 3,8 with sodium hydroxide solution 1 mol/l (5.1.5), and dilute to
500 ml with water. This solution is stable for three months if it is kept in the dark and refrigerated (5 ± 3) °C.
NOTE See Annex C for details of an alternative modified buffer to overcome flow stability problems observed
with some continuous flow systems caused by the high concentration of citric acid in this reagent.
5.2.2 Zinc sulfate solution
Dissolve 10 g of zinc sulfate heptahydrate, ZnSO ∙ 7 H O, in 750 ml water, mix and dilute to 1 000 ml
4 2
with water. This solution is stable at least 1 year.
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SIST EN ISO 17380:2013
ISO 17380:2013(E)
5.2.3 Buffer solution for photometric determination (pH = 5,2)
Dissolve 2,3 g of sodium hydroxide in 500 ml water. Add 20,5 g of potassium hydrogen phthalate
(KHC H O ) and dilute to 975 ml with water. Adjust the pH of the solution to 5,2 with hydrochloric
8 4 4
acid 1 mol/l (5.1.2) or sodium hydroxide solution 1 mol/l (5.1.5), add 1 ml detergent solution (5.1.7)
and dilute to 1 000 ml with water. This solution is stable for three months if it is kept in the dark and
refrigerated (5 ± 3) °C.
5.2.4 Chloramine-T solution
Dissolve 2,0 g of chloramine-T, C H ClNNaO S ∙ 3 H O in 1 000 ml water. This solution is stable for one
7 7 2 2
month if it is kept in the dark and refrigerated (5 ± 3) °C.
5.2.5 Colour reagent (pH = 5,2)
Dissolve 7,0 g of solid sodium hydroxide NaOH in 500 ml water. Add 16,8 g of 1,3-dimethylbarbituric
acid, C H N O , and 13,6 g of pyridine-4-carboxylic acid, C H NO , and dilute to 975 ml with water. If
6 8 2 3 6 5 2
necessary, adjust the pH of the solution to 5,2 with hydrochloric acid 1 mol/l (5.1.2) or sodium hydroxide
solution 1 mol/l (5.1.5) and then dilute to 1 000 ml with water.
Stir vigorously for 1 h at 30 °C and then filter over a pleated filter. This solution is stable for three months
provided it is stored in the dark and refrigerated (5 ± 3) °C, and filtered over a pleated filter before use.
5.2.6 Rinse solution for the sampler (0,025 mol/l sodium hydroxide)
Add 25 ml sodium hydroxide solution 1 mol/l (5.1.5) and dilute to 1 000 ml with water. This solution is
stable for three months.
5.3 Standard solutions for cyanide determination
5.3.1 Stability
The concentrated standard solutions (5.3.2.1, 5.3.3.1 and 5.3.3.3) are stable for at least three months
and the diluted standard solutions for at least one week provided they are stored in the dark and
refrigerated (5 ± 3) °C.
5.3.2 Potassium cyanide standard solutions
5.3.2.1 Cyanide standard solution corresponding to 100 mg/l of cyanide ion
Dissolve 0,250 g of potassium cyanide KCN in sodium hydroxide solution 0,025 mol/l (5.1.6) and in a
volumetric flask of 1 000 ml make up with sodium hydroxide solution 0,025 mol/l (5.1.6).
Transfer, by means of a pipette, into a beaker, 10 ml high standard cyanide solution with a content of
100 mg/l CN (5.3.2.1). Add 0,25 ml indicator solution (5.1.8). Perform a titration with the silver nitrate
solution (5.1.10) until the colour changes from yellow to yellow-red (titration volume V ).
1
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SIST EN ISO 17380:2013
ISO 17380:2013(E)
Calculate the cyanide content in the standard cyanide solution with Formula (1):
ρ =⋅Vc ⋅MV/ (1)
CN 1 (AgNO) (2CN)
3
where
ρ is the cyanide content in the standard cyanide solution in milligrams per litre;
CN
V is the quantity of silver nitrate solution (5.1.9) used in millilitres;
1
c
(AgNO)
3 is the concentration of silver nitrate in millimoles per litre;
M is the molar mass of 2 CN ( = 52 g/mol);
(2CN)
V is the volume of the standard cyanide solution in millilitres (in this case = 10 ml).
NOTE Commercially available standard solutions may also be used (e.g. potassium tetracyanozincate,
K Zn(CN) , c(CN = 1 000 ± 2 mg/l)).
2 4
5.3.2.2 Cyanide standard solution corresponding to 1 mg/l of cyanide ion
Transfer, by means of a pipette, 2,5 ml of the 100 mg/l cyanide solution (5.3.2.1) in a volumetric flask of
250 ml and fill to the mark with sodium hydroxide solution 0,025 mol/l (5.1.6).
5.3.3 Control solutions
5.3.3.1 Potassium thiocyanate solution corresponding to 100 mg/l of cyanide ion
Dissolve 0,373 g of potassium thiocyanate, KSCN (dried at 105 °C, stored in a desiccator), in sodium
hydroxide solution 0,025 mol/l (5.1.6) and in a 1000 ml volumetric flask make up with sodium hydroxide
solution 0,025 mol/l (5.1.6).
5.3.3.2 Potassium thiocyanate solution corresponding to 1 mg/l of cyanide ion
Transfer, by means of a pipette, 2,5 ml of the 100 mg/l standard thiocyanate solution (5.3.3.1) (equivalent
to 100 mg/l CN¯) into a 250 ml volumetric flask of and fill to the mark with sodium hydroxide solution
0,025 mol/l (5.1.6).
5.3.3.3 Potassium hexacyanoferrate solution corresponding to 100 mg/l of cyanide ion
Dissolve 0,211 g of potassium hexacyanoferrate, K [Fe[III](CN) ] (dried at 105 °C, stored in a desiccator),
3 6
in sodium hydroxide solution 0,025 mol/l (5.1.6) and in a volumetric flask of 1 000 ml make up with
sodium hydroxide solution 0,025 mol/l (5.1.6).
5.3.3.4 Potassium hexacyanoferrate solution corresponding to 1 mg/l of cyanide ion
Transfer, by means of a pipette, 2,5 ml potassium hexacyanoferrate solution (5.3.3.3) (equivalent to
100 mg/l CN¯) into a 250 ml volumetric flask and fill to the mark with sodium hydroxide solution
0,025 mol/l (5.1.6).
5.3.3.5 Potassium hexacyanoferrate solution corresponding to 0,1 mg/l of cyanide ion
Transfer, by means of a pipette, 10 ml of 1 mg/l potassium hexacyanoferrate[III] solution (5.3.3.4) into
a 100 ml volumetric flask and make up to t
...
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