EN ISO 9963-2:1995

Water quality - Determination of alkalinity - Part 2: Determination of carbonate alkalinity (ISO 9963-2:1994)

Specifies a method for the titrimetric determination of carbonate alkalinity in natural and drinking water. The method is intended for samples with a carbonate alkalinity between 0,01 mmol/l and 4 mmol/l. For samples containing higher concentrations of alkalinity, a smaller test portion can be used for analysis.

Wasserbeschaffenheit - Bestimmung der Alkalinität - Teil 2: Bestimmung der Carbonatalkalinität (ISO 9963-2:19954)

Dieser Teil von ISO 9963 legt ein Verfahren zur titrimetrischen Bestimmung der Carbonatalkalinität fest. Durch die Wahl eines höheren pH-Werts für den Endpunkt als bei dem in ISO 9963-1 festgelegten Verfahren, verringert sich der Einfluß anderer Wasserstoffakzeptoren, wie beispielsweise Huminsäuren. Das Verfahren ist für Proben geeignet, deren Carbonatalkalinität zwischen 0,01 mmol/l und 4 mmol/l (gerechnet als H+-Äquivalente) liegt. Bei Proben mit höheren Konzentrationen kann eine kleinere Abnahme zur Analyse verwendet werden.

Qualité de l'eau - Détermination de l'alcalinité - Partie 2: Détermination de l'alcalinité carbonate (ISO 9663-2:1994)

La présente partie de l'ISO 9963 prescrit une méthode pour la détermination titrimétrique de l'alcalinité carbonate des eaux naturelles et des eaux potables. En utilisant une valeur de pH plus élevée pour le point de virage que dans la méthode spécifiée dans l'ISO 9963-1, l'influence d'autres prototypes tels que les anions ou les acides humiques est réduite par cette méthode. La méthode est destinée aux échantillons ayant une alcalinité carbonate comprise entre 0,01 mmol/l et 4 mmol/l (en équivalent H+). Pour des échantillons contenant de plus fortes concentrations, une portion d'essai plus faible peut être utilisée. Dans ce contexte, l'alcalinité carbonate est souvent appelée alcalinité totale et possède habituellement la même valeur numérique que celle attribuée à l'alcalinité du méthylorange (alcalinité MO). La détection du point de virage à l'aide d'un pH-mètre est moins sujette aux interférences que l'usage d'un indicateur.

Kakovost vode - Določanje alkalitete - 2. del: Določanje karbonatne alkalitete (ISO 9963-2:1994)

General Information

• Status: Published
• Publication Date: 12-Dec-1995
• Withdrawal Date: 29-Jun-1996
• ICS: 13.060.30 - Sewage water
• Technical Committee: CEN/TC 230 - Water analysis
• Drafting Committee: CEN/TC 230 - Water analysis
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 21-May-2008
• Completion Date: 21-May-2008
• Ref Project: SIST EN ISO 9963-2:1998 - Water quality - Determination of alkalinity - Part 2: Determination of carbonate alkalinity (ISO 9963-2:1994)

Relations

• Parent: EN ISO 9963-1:1995 - Water quality - Determination of alkalinity - Part 1: Determination of total and composite alkalinity (ISO 9963-1:1994)
• Effective Date: 22-Dec-2008

Overview

EN ISO 9963-2:1995 is an internationally recognized standard that specifies a titrimetric method for determining carbonate alkalinity in natural and drinking water. Developed under the guidance of the International Organization for Standardization (ISO) and adopted by CEN, this standard is vital for water quality analysis, especially for samples with carbonate alkalinity concentrations between 0.01 mmol/l and 4 mmol/l. For higher concentrations, the method allows for smaller test portions to ensure accurate measurement.

The method uses hydrochloric acid titration with a pH endpoint of 5.4, enabling precise quantification of carbonate alkalinity while minimizing interference from other hydrogen acceptors such as humic acids. The procedure can be performed using either pH-meter endpoint detection or colorimetric indicators, making it flexible for different laboratory setups.

Key Topics

• Scope and Application: Quantitative titrimetric determination of carbonate alkalinity in natural and drinking water samples.
• Sample Concentration Range: Effective for carbonate alkalinity from 0.01 mmol/l to 4 mmol/l.
• Measurement Principle: Titration with hydrochloric acid under carbon dioxide-free conditions, stabilizing endpoint at pH 5.4.
• Endpoint Detection Methods:
  • pH-meter measurement with an accuracy of ±0.05 pH units.
  • Visual indicator method using a mixed indicator solution (methyl red and bromocresol green).
• Reagents and Solutions:
  • Standardized hydrochloric acid (~0.020 mol/l).
  • Sodium carbonate solution for standardization.
  • Carbon dioxide-free gas for removing CO2 during titration.
• Sample Handling: Advises immediate analysis or refrigeration at 4–8 °C to prevent sample degradation.
• Calculation: Formula-based calculation converting titrated volumes into carbonate alkalinity concentration, expressed in millimoles per litre.
• Precision and Accuracy: Established interlaboratory tests demonstrate a typical coefficient of variation around 2-4%, supporting reliability.
• Interference Minimization: Elevated pH endpoint reduces interference from non-carbonate substances such as ammonia and organic acids.

Applications

• Drinking Water Quality Monitoring: Ensures compliance with health and safety standards by accurately quantifying carbonate alkalinity.
• Environmental Water Testing: Analyzing lakes, rivers, and groundwater for alkalinity to assess chemical composition and corrosivity.
• Water Treatment Process Control: Monitoring raw and treated water alkalinity to optimize chemical dosing and treatment effectiveness.
• Research and Development: Provides consistent data for studies involving aquatic chemistry and water buffering capacity.
• Regulatory Compliance: Assists laboratories and water utilities in adhering to water quality regulations that specify alkaline content limits.

Related Standards

• EN ISO 9963-1:1994: Determination of total and composite alkalinity in water - a complementary method covering total alkalinity analysis.
• ISO 3696:1987: Standard for water quality used in analytical laboratory testing.
• ISO 5667-2:1991: Guidelines on sampling techniques for water analysis.
• ISO 6107-2:1989: Vocabulary specific to water quality terminology.
• ISO 385-1:1984: Laboratory glassware specifications, including burettes used for titration.
• IEC 746-2:1982: Performance criteria for electrochemical analyzers, relevant for pH measurement equipment.

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Keywords: carbonate alkalinity, water quality standard, titrimetric determination, drinking water analysis, alkalinity testing method, pH endpoint titration, EN ISO 9963-2, natural water testing, water treatment monitoring, standardized water analysis, carbonate buffering, pH-meter alkalinity test.

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-1998
.DNRYRVWYRGH'RORþDQMHDONDOLWHWHGHO'RORþDQMHNDUERQDWQHDONDOLWHWH,62

Water quality - Determination of alkalinity - Part 2: Determination of carbonate alkalinity
(ISO 9963-2:1994)
Wasserbeschaffenheit - Bestimmung der Alkalinität - Teil 2: Bestimmung der
Carbonatalkalinität (ISO 9963-2:19954)
Qualité de l'eau - Détermination de l'alcalinité - Partie 2: Détermination de l'alcalinité
carbonate (ISO 9663-2:1994)
Ta slovenski standard je istoveten z: EN ISO 9963-2:1995
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
IS0
STANDARD
First edition
1994-l I-1 5
Water quality - Determination of
alkalinity -
Part 2:
Determination of carbonate alkalinity
Qua/it6 de I’eau - 06 termination de I’alcalinit6 -
Partie 2: D6 termha tion de I ‘alcalinit6 carbonate
Reference number
IS0 99632:1994(E)
IS0 9963-2: 1994(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
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. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
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.
International Standard IS0 9963-2 was prepared by Technical Committee
lSO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical,
biochemical methods.
IS0 9963 consists of the following parts, under the general title Water
quality - Determination of alkalinity:
- Part 1: Determination of total and composite alkalinity
- Part 2: Determination of carbonate alkalinity
Annexes A and B of this part of IS0 9963 are for information only.
0 IS0 1994
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
INTERNATIONAL STANDARD 0 IS0 IS0 9963-2: 1994(E)
Water quality - Determination of alkalinity -
Part 2:
Determination of carbonate alkalinity
IS0 385-l :1984, Laboratory glassware - Burettes -
1 Scope
Part 1: General requirements.
This part of IS0 9963 specifies a method for the
IS0 3696: 1987, Water for analytical laboratory use -
titrimetric determination of carbonate alkalinity in
Specification and test methods.
natural and drinking water. Using a higher pH value for
than the method specified in
the endpoint
IS0 5667-2:1991, Water quality - Sampling -
IS0 9963-1, the influence of other hydrogen ac-
Part 2: Guidance on sampling techniques.
ceptors, such as anions of humic acids, is reduced by
the procedure.
IS0 6107-2:1989, Water quality - Vocabulary -
Part 2.
The method is intended for samples with a carbonate
alkalinity between 0,Ol mmol/l and 4 mmol/l (as H+
IS0 9963-l :l994, Water quality - Determination of
equivalents). For samples containing higher concen-
alkalinity - Part 1: Determination of total and com-
trations of alkalinity, a smaller test portion can be used
posite alkalinity.
for analysis.
IEC 746-2:1982, Expression of performance of
In this context, carbonate alkalinity is often called total
electrochemical analyzers - Part 2: pH value.
alkalinity and usually has nearly the same numerical
value as methyl orange alkalinity (MO-alkalinity).
The endpoint detection, using a pH-meter is less
3 Definition
prone to interferences than the use of the indicator.
For the purposes of this part of IS0 9963, the follow-
ing definition applies.
3.1 alkalinity (A): The quantitative capacity of
2 Normative references
aqueous media to react with hydrogen ions.
[ISO 6107-21
The following standards contain provisions which,
through reference in this text, constitute provisions
In this method, the endpoint is chosen in such a way
of this part of IS0 9963. At the time of publication, the
as to permit the full neutralization of the carbonate
editions indicated were valid. All standards are subject
system.
to revision, and parties to agreements based on this
part of IS0 9963 are encouraged to investigate the
A = c(HC0,) + 2c(CO;-) + c(OH-) + c(X) - c(H+)
possibility of applying the most recent editions of the
standards indicated below. Members of IEC and IS0 Usually proton acceptors (X) other than the carbonate
maintain registers of currently valid International system are present in low concentrations and can of-
Standards. ten be disregarded. Examples of such buffering sub-
0 IS0
IS0 9963-2: 1994(E)
stances are ammonia, phosphate, and anions of
5 Reagents
humic and other organic acids.
Use only reagents of recognized analytical grade.
Commercially available, ready-made solutions may be
used.
4 Principle
5.1 Water, grade 2 in accordance with IS0 3696,
Alkalinity is determined by titration with hydrochloric
free of interfering concentrations of acid or alkali and
acid, with simultaneous removal of carbon dioxide. In
with a conductivity of less than 0,l mS/m.
this way, a precise endpoint independent of the initial
concentration of alkalinity can be used. The endpoint
preferably needs to be as close to neutrality as poss- 5.2 Gas, free from carbon dioxide, nitrogen or al-
ternatively a gas free from carbon dioxide obtained by
ible but still low enough to allow the removal of car-
passing air through a standing tube filled with soda
bon dioxide produced. In this part of IS0 9963, the
lime or another compound that absorbs carbon diox-
endpoint is set at pH 5,4, since the pH value can
easily be determined with the indicator chosen. The ide. Then pass the gas through a wash bottle con-
induced systematic error is corrected by titrating a taining water and subsequently the gas distribution
blank. tube (see figure 1).
Volume about 75 ml
Glass wool
Poros
Soda lime
or equivalent
Air
Filter funnel
c
Figure 1 - Principle for absorption of carbon dioxide from air

0 IS0 IS0 9963-2: 1994(E)
where
5.3 Mixed indicator pH 5,4.
c(HCI) is the concentration, expressed in
Dissolve 0,040 g + 0,005 g of methyl red and
moles per litre, of the hydrochloric
0,060 g + 0,005 g if bromocresol green in 100 ml of
acid solution (5.5);
ethanol r> 90 % (WV)]. Neutralize the solution with
about 2 ml of 0,l mol/l sodium hydroxide until a
m is the mass, in grams, of sodium
brown colour appears. Check the neutrality of the in-
carbonate taken for the preparation
dicator solution by titration to endpoint of one sample.
of solution 5.4;
If the brown colour does not remain after the addition
of 10 more drops of the indicator, adjust the pH of the
is the volume, in millilitres, of sodium
indicator solution. Stored in an amber glas
...