SIST ISO 6058:1996

Water quality -- Determination of calcium content -- EDTA titrimetric method

Describes a procedure for ground waters, surface waters and drinking waters. It can also be used for municipal and industrial raw waters, provided they do not contain interfering amounts of heavy metals. The procedure is not applicable to sea waters and other similar waters having a high concentration of salts. It is applicable to waters with contents ranging from 2 to 100 mg/l. For higher contents a diluted sample is to be used.

Qualité de l'eau -- Dosage du calcium -- Méthode titrimétrique à l'EDTA

Kakovost vode - Ugotavljanje vsebnosti kalcija - Titrimetrijska metoda z EDTA

General Information

• Status: Published
• Publication Date: 30-Sep-1996
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: KAV - Water quality
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Oct-1996
• Due Date: 01-Oct-1996
• Completion Date: 01-Oct-1996
• Ref Project: ISO 6058:1984 - Water quality - Determination of calcium content - EDTA titrimetric method

Overview

SIST ISO 6058:1996 specifies a standardized EDTA titrimetric method for the determination of calcium content in water. This international standard outlines a precise procedure applicable to various water types including groundwater, surface water, and drinking water. It is also suitable for municipal and industrial raw waters, assuming no significant interference from heavy metals. Notably, this method is unsuitable for seawater or similar waters with high salt concentrations. The standard covers calcium concentrations ranging from 2 to 100 mg/L, with provisions for dilution of samples exceeding this range.

Developed by ISO Technical Committee ISO/TC 147 on water quality, ISO 6058 provides clear guidance for laboratory analysis to ensure consistent and reliable measurement of calcium levels critical for assessing water quality.

Key Topics

• Scope and Applicability
  Designed for calcium determination in freshwaters and potable water sources; unsuitable for seawater due to high salt interference. Applicable concentration range is 2 to 100 mg/L of calcium; higher concentrations require sample dilution.

• Principle of Method
  Calcium ions are titrated using a disodium salt of ethylenediaminetetraacetic acid (EDTA) solution at pH 12–13. The indicator-murexide (HSN)-forms a red complex with calcium and changes color to light blue at the titration endpoint. Magnesium and other potential interfering ions are either precipitated out or controlled by the pH adjustment.

• Reagents and Equipment
  Analytical grade reagents including sodium hydroxide solution, titrated EDTA solution (approx. 10 mmol/L), and the HSN indicator are used. Standard laboratory glassware such as 25 mL burettes (ISO/R 385 class A) and volumetric flasks are specified. Calibration with a reference calcium standard is required for accuracy.

• Sample Preparation and Analysis
  Samples are neutralized if acidified during collection, diluted if above concentration limits, and titrated immediately after addition of reagents. The endpoint is carefully observed by color change, with precise volumes recorded for concentration calculation.

• Interferences and Limitations
  Certain metal ions-aluminum, iron, lead, copper, zinc, cobalt, manganese, and others-may interfere by either forming complexes or causing turbidity at the endpoint. The method suggests additions like sodium cyanide or triethanolamine to mitigate some interferences, but for heavily contaminated waters, alternative instrumental methods such as atomic absorption spectroscopy (ISO 7980) are recommended.

Applications

• Water Quality Monitoring
  Essential for routine analysis in water treatment plants to monitor hardness and calcium levels that affect scaling and corrosion.

• Environmental Assessment
  Helps in evaluating calcium content in natural waters for ecological studies and environmental impact assessments.

• Industrial Water Management
  Used in industries to monitor raw water and process water for calcium content to prevent operational issues related to water hardness.

• Drinking Water Compliance
  Supports compliance testing with regulatory standards on calcium in potable water supplies, ensuring safe and palatable water.

Related Standards

• ISO 5667 Series – Guidelines for sampling water, relevant for collecting samples compliant with ISO 6058 procedures.
• ISO 7980 – Atomic absorption spectrometric methods for the determination of calcium, suggested for analysis where interference affects EDTA titration results.
• ISO/R 385 – Specification for the calibration and use of laboratory burettes.
• ISO 30511 – Laboratory glassware specifications, relevant for ensuring accuracy of volumetric equipment used in titrations.

---

Keywords: ISO 6058, water quality standard, calcium determination, EDTA titrimetric method, water analysis, calcium content, water hardness, water testing, water sampling, interference mitigation, analytical water testing.

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-1996
Kakovost vode - Ugotavljanje vsebnosti kalcija - Titrimetrijska metoda z EDTA
Water quality -- Determination of calcium content -- EDTA titrimetric method
Qualité de l'eau -- Dosage du calcium -- Méthode titrimétrique à l'EDTA
Ta slovenski standard je istoveten z: ISO 6058:1984
ICS:
13.060.50 3UHLVNDYDYRGHQDNHPLþQH Examination of water for
VQRYL chemical substances
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON.MEIK,QYHAPOflHAR OPrAHM3ALWlfl IlO CTAH~APTM3AL&Wl.ORGANlSATlON INTERNATIONALE DE NORMALISATION
Water quality - Determination of calcium content -
EDTA titrimetric method
Qua/it& de l’eau - Dosage du calcium - Mthode titrimtS trique ;i I ’ED TA
First edition - 1984-06-01
UDC 543.3 : 543.24 : 546.41 Ref. No. IS0 6058-1984 (E)
determination of content, calcium, volumetric analysis.
Descriptors : water, quality, chemical analysis,
Price based on 3 pages
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of developing International
Standards is carried out through IS0 technical committees. Every member body
interested in a subject for which a technical committee has been authorized 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 IS0 Council.
International Standard IS0 6058 was developed by Technical Committee ISO/TC 147,
Water-quality, and was circulated to the member bodies in January 1983.
It has been approved by the member bodies of the following countries:
Australia
Hungary Poland
Austria
India Romania
Belgium
Iran South Africa, Rep. of
Brazil
Iraq Spain
Canada Italy Sweden
China
Japan Switzerland
Czechoslovakia Korea, Dem. P. Rep. of Thailand
Denmark
Korea, Rep. of United Kingdom
Finland Netherlands USSR
France New Zealand
Germany, F. R. Norway
No member body expressed disapproval of the document.
0 International Organization for Standardization, 1984
Printed in Switzerland
IS0 6058-1984 (E)
INTERNATIONAL STANDARD
Determination of calcium content -
Water quality -
EDTA titrimetric method
1 Scope and field of application 4 Reagents
This International Standard specifies a titrimetric method using During the analysis, use only reagents of recognized analytical
ethylenediaminetetraacetic acid (EDTA) for the determination grade and only distilled water or water of equivalent purity.
of the calcium content of ground waters, surface waters and
drinking waters. It can also be used for municipal and industrial
raw waters, provided they do not contain interfering amounts 4.1 Sodium hydroxide, 2 mol/l, solution.
of heavy metals.
Dissolve 8 g of sodium hydroxide in 100 ml of freshly distilled
The method is not applicable to sea waters and other similar water. Store in a polyethylene bottle.
waters with a high concentration of salts. It is applicable to
waters with calcium contents ranging from 2 to 100 mg/I (0,05 NOTE - Take precautions to avoid contamination by atmospheric
carbon dioxide.
to 2,5 mmol/l).
For waters containing more calcium than 100 mg/l, a diluted
sample shall be used. 4;2 EDTA, standard volumetric solution,
c(Na2EDTA) = 10 mmol/l.
4.2.1 Preparation
2 References
Dry a portion of the disodium salt of EDTA dihydrate
IS0 385/l, Laboratory glassware - Burettes - Part 7:
K10H,,N,08Na2~2H20) at 80 OC for 2 h, dissolve 3,725 g of the
General requirements. 1)
dry salt in water and dilute to 1 000 ml in a volumetric flask.
IS0 5667, Water quality - Sampling -
Store the EDTA solution in a polyethylene bottle and check the
Part 7: Guidance on the design of sampling programmes.
concentration at regular intervals.
Part 2: Guidance on sampling techniques.
Part 3: Guidance on the preservation and handling of
4.2.2 Standardization
samples. 2)
Standardize the solution (4.2.1) against the calcium standard
reference solution (4.3) by the procedure described in clause 7.
3 Principle
Use 20,O ml of the calcium standard reference solution (4.3)
and dilute to 50 ml.
Complexometric titration of calcium ions with an aqueous solu-
tion of the disodium salt of EDTA at a pH value of between 12
4.2.3 Calculation of the concentration
and 13. HSN, which forms a red complex with calcium, is used
as the indicator. Magnesium is precipitated as the hydroxide
The concentration *of the EDTA solution, cl, expressed in
and does not interfere with the determination.
millimoles per litre, is given by the equation
In the titration, the EDTA first reacts with the free calcium ions
and then with the calcium ions combined with the indicator. e2 Vl
Cl = -
The indicator then changes its colour from red to bright blue.
b
1) At present at the stage of draft. (Partial revision of ISO/R 385-1964.)
2) At present at the stage of draft.
IS0 60584984 (El
7 Procedure
is the concentration, expressed in millimoles per litre, of
C2
the calcium standard reference solution (4.3) ;
7.1 Preparation of the test portion
r/l is the volume, in mil lilitres, of the calcium standard
...

International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON.MEIK,QYHAPOflHAR OPrAHM3ALWlfl IlO CTAH~APTM3AL&Wl.ORGANlSATlON INTERNATIONALE DE NORMALISATION
Water quality - Determination of calcium content -
EDTA titrimetric method
Qua/it& de l’eau - Dosage du calcium - Mthode titrimtS trique ;i I ’ED TA
First edition - 1984-06-01
UDC 543.3 : 543.24 : 546.41 Ref. No. IS0 6058-1984 (E)
determination of content, calcium, volumetric analysis.
Descriptors : water, quality, chemical analysis,
Price based on 3 pages
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of developing International
Standards is carried out through IS0 technical committees. Every member body
interested in a subject for which a technical committee has been authorized 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 IS0 Council.
International Standard IS0 6058 was developed by Technical Committee ISO/TC 147,
Water-quality, and was circulated to the member bodies in January 1983.
It has been approved by the member bodies of the following countries:
Australia
Hungary Poland
Austria
India Romania
Belgium
Iran South Africa, Rep. of
Brazil
Iraq Spain
Canada Italy Sweden
China
Japan Switzerland
Czechoslovakia Korea, Dem. P. Rep. of Thailand
Denmark
Korea, Rep. of United Kingdom
Finland Netherlands USSR
France New Zealand
Germany, F. R. Norway
No member body expressed disapproval of the document.
0 International Organization for Standardization, 1984
Printed in Switzerland
IS0 6058-1984 (E)
INTERNATIONAL STANDARD
Determination of calcium content -
Water quality -
EDTA titrimetric method
1 Scope and field of application 4 Reagents
This International Standard specifies a titrimetric method using During the analysis, use only reagents of recognized analytical
ethylenediaminetetraacetic acid (EDTA) for the determination grade and only distilled water or water of equivalent purity.
of the calcium content of ground waters, surface waters and
drinking waters. It can also be used for municipal and industrial
raw waters, provided they do not contain interfering amounts 4.1 Sodium hydroxide, 2 mol/l, solution.
of heavy metals.
Dissolve 8 g of sodium hydroxide in 100 ml of freshly distilled
The method is not applicable to sea waters and other similar water. Store in a polyethylene bottle.
waters with a high concentration of salts. It is applicable to
waters with calcium contents ranging from 2 to 100 mg/I (0,05 NOTE - Take precautions to avoid contamination by atmospheric
carbon dioxide.
to 2,5 mmol/l).
For waters containing more calcium than 100 mg/l, a diluted
sample shall be used. 4;2 EDTA, standard volumetric solution,
c(Na2EDTA) = 10 mmol/l.
4.2.1 Preparation
2 References
Dry a portion of the disodium salt of EDTA dihydrate
IS0 385/l, Laboratory glassware - Burettes - Part 7:
K10H,,N,08Na2~2H20) at 80 OC for 2 h, dissolve 3,725 g of the
General requirements. 1)
dry salt in water and dilute to 1 000 ml in a volumetric flask.
IS0 5667, Water quality - Sampling -
Store the EDTA solution in a polyethylene bottle and check the
Part 7: Guidance on the design of sampling programmes.
concentration at regular intervals.
Part 2: Guidance on sampling techniques.
Part 3: Guidance on the preservation and handling of
4.2.2 Standardization
samples. 2)
Standardize the solution (4.2.1) against the calcium standard
reference solution (4.3) by the procedure described in clause 7.
3 Principle
Use 20,O ml of the calcium standard reference solution (4.3)
and dilute to 50 ml.
Complexometric titration of calcium ions with an aqueous solu-
tion of the disodium salt of EDTA at a pH value of between 12
4.2.3 Calculation of the concentration
and 13. HSN, which forms a red complex with calcium, is used
as the indicator. Magnesium is precipitated as the hydroxide
The concentration *of the EDTA solution, cl, expressed in
and does not interfere with the determination.
millimoles per litre, is given by the equation
In the titration, the EDTA first reacts with the free calcium ions
and then with the calcium ions combined with the indicator. e2 Vl
Cl = -
The indicator then changes its colour from red to bright blue.
b
1) At present at the stage of draft. (Partial revision of ISO/R 385-1964.)
2) At present at the stage of draft.
IS0 60584984 (El
7 Procedure
is the concentration, expressed in millimoles per litre, of
C2
the calcium standard reference solution (4.3) ;
7.1 Preparation of the test portion
r/l is the volume, in mil lilitres, of the calcium standard
The test portion should contain between 2 and 100 mg/l (0,05
reference solution;
and 2,5 mmol/l) of calcium. If a concentration in excess of
100 mg/l (2,5 mmol/l) is expected, dilute a known volume of
V2 is the volume, in millilitres, of the EDTA solution used
test solution so as to bring the concentration within the re-
for the standardization.
quired range and record the dilution factor F.
If the test portions have been acidified for preservation,
neutralize them with the calculated amounts of the so
...

Norme internationale
INTERNATIONAL ORGANIZATION FOR STANDARDIZATIONeME)I(C1YHAPOAHAR OPTAHM3AWlR fl0 CTAHAAPTM3AL\Mkl~ORGANISATlON INTERNATIONALE DE NORMALISATION
Qualité de l’eau - Dosage du calcium - Méthode
titrimétrique à I’EDTA
M/ater quality - Determina tion of calcium content - ED TA titrime trie me thod
Première édition - 1984-06-01
CDU 543.3 : 543.24 : 546.41 Réf. no : ISO 6058-1984 (FI
eau, qualité, analyse chimique, dosage, calcium, méthode volumétrique.
Descripteurs :
Prix basé sur 3 pages
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale
d’organismes nationaux de normalisation (comités membres de I’ISO). L’élaboration
des Normes internationales est confiée aux comités techniques de I’ISO. Chaque
comite membre intéressé par une étude a le droit de faire partie du comite technique
correspondant. Les organisations internationales, gouvernementales et non gouverne-
mentales, en liaison avec I’ISO, participent également aux travaux.
Les projets de Normes internationales adoptés par les comités techniques sont soumis
aux comités membres pour approbation, avant leur acceptation comme Normes inter-
nationales par le Conseil de I’ISO.
La Norme internationale ISO 6058 a été élaborée par le comité technique ISO/TC 147,
Qua/i&? de /‘eau, et a été soumise aux comités membres en janvier 1983.
Les comites membres des pays suivants l’ont approuvée:
Afrique du Sud, Rép. d’
Espagne Pays- Bas
Allemagne, R. F.
Finlande Pologne
Australie
France Roumanie
Autriche
Hongrie Royaume-Uni
Belgique
Inde Suéde
Bresil Iran
Suisse
Canada
Iraq Tchécoslovaquie
Chine
Italie Thailande
Corée, Rép. de Japon URSS
Corée, Rép. dem. p. de
Norvége
Danemark Nouvelle-Zélande
Aucun comité membre ne l’a désapprouvée.
@ Organisation internationale de normalisation, 1984 0
Imprimé en Suisse
ISO 6058-1984 (FI
NORME INTERNATIONALE
calcium - Méthode
Qualité de l’eau - Dosage du
titrimétrique à I’EDTA
1 Objet et domaine d’application 4 Réactifs
La présente Norme internationale spécifie une methode titrimé- Au cours de l’analyse, utiliser uniquement des réactifs de qua-
trique à I’EDTA pour le dosage du calcium dans les eaux souter- lit6 analytique reconnue, et de l’eau distillée ou de l’eau de
raines, les eaux de surface et les eaux de boisson. Elle peut
pureté au moins équivalente. z
aussi être utilisée pour les eaux résiduaires urbaines et les eaux
brutes industrielles, à condition qu’elles ne contiennent pas de
métaux lourds en quantités interferentes. 4.1 Hydroxyde de sodium, solution 2 mol/l.
La méthode n’est pas applicable aux eaux de mer et eaux du
Dissoudre 8 g d’hydroxyde de sodium dans 100 ml d’eau fraî-
même type à forte teneur en sels. Elle est applicable aux eaux chement distillée. Conserver dans une bouteille en polyéthy-
dont la teneur en calcium varie de 2 à 100 mg/I (0,05 à Iène.
2,5 mmol/l).
NOTE - Prendre des précautions afin d’éviter la contamination par le
Pour les eaux contenant plus de 100 mg/I de calcium, une dilu- dioxyde de carbone atmosphérique.
tion de l’échantillon doit être effectuée.
4.2 EDTA, solution titrée, c(Na2EDTA) f= 10 mmol/l.
2 Références
4.2.1 Préparation
ISO 30511, Verrerie de laboratoire - Burettes - Partie 7: Spé-
Sécher une portion d’EDTA, sel disodique dihydraté
cifïca tions générslles 1).
K10HI~N208Na2~2H20) à 80 OC pendant 2 h, dissoudre 3,725 g
ISO 5667, Qualit de l’eau - Échantillonnage - du sel sec dans de l’eau et diluer a 1 000 ml dans une fiole jau-
gée.
Partie 1: Guide général pour l’établissement des programmes
d’échantillonnage.
Conserver la solution d’EDTA dans une bouteille en polyéthy-
Partie 2: Guide général sur les techniques d’échantillonnage.
Iéne et en vérifier la concentration de temps à autre.
Partie 3: Guide général sur la conservation et la manipulation
des khan tillons. 2)
4.2.2 Étalonnage
Étalonner la solution (4.2.1) avec une solution étalon de réfé-
rence de calcium (4.3) comme spécifié dans le chapitre 7.
3 Principe
Pour l’étalonnage, utiliser 20,O ml de la solution étalon de réfé-
Titrage des ions calcium avec une solution aqueuse de sel diso-
rence de calcium (4.3) et diluer à 50 ml avec de l’eau.
dique d’acide éthyléne-diamine tétraacétique (EDTA) à un pH
compris entre 12 et 13. Le HSN, qui forme un complexe rouge
avec le calcium, est utilisé comme indicateur. Le magnésium
4.2.3 Calcul de la concentration
est précipité sous forme d’hydroxyde et n’interfère pas lors du
dosage.
La concentration de la solution d’EDTA, cl, exprimée en milli-
moles par litre, est donnée par l’équation
Lors du titrage, I’EDTA réagit tout d’abord avec les ions cal-
cium libres, puis avec les ions calcium combinés avec I’indica- C2 5
Cl = -
teur qui vire alors de la couleur rouge à la couleur bleu clair.
Y2
1) Actuellement au stade de projet. (Révision partielle de I’ISO/ R 3854964.)
2) Actuellement au stade de projet.
ISO 6058-4984 (FI
où 7 Mode opératoire
c2 est la concentration, exprimée en millimoles par litre, de
la solution étalon de référence de calcium (4.3);
7.1 Préparation de l’échantillon
1/1 est le volume, en millilitres, de la solution étalon de
référence de calcium (4.3); L’échantillon pour analyse doit contenir entre 2 et 100 mg/l
(0,05 et 2,5 mmol/l) de calcium.
V2 est le volume, en millilitres, de la solution d’EDTA, uti-
lisé pour l’étalonnage.
Si une concentration supérieure à 100 mg/1 (2,5 mmol/l) est
attendue, diluer un volume connu de l’échantillon afin de rame-
ner la concentration dans la zone désirée, et noter le facteur de
4.3 Calcium, solution étalon de référence,
dilution F.
cKaCOJ) = 10 mmol/l.
Si les prises d’essai ont été acidifiées pour conservation, les
Sécher un échantillon de carbonate de calcium pur pendant 2
...