SIST EN ISO 3696:1998

SLOVENSKI STANDARD
SIST EN ISO 3696:1998
01-maj-1998
Voda za analitsko laboratorijsko uporabo - Specifikacija in preskusne metode (ISO
3696:1987)
Water for analytical laboratory use - Specification and test methods (ISO 3696:1987)
Wasser für analytische Laborzwecke - Spezifikation und Prüfverfahren (ISO 3696:1987)
Eau pour laboratoire a usage analytique - Spécification et méthodes d'essai (ISO
3696:1987)
Ta slovenski standard je istoveten z: EN ISO 3696:1995
ICS:
71.040.01 Analitska kemija na splošno Analytical chemistry in
general
SIST EN ISO 3696:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 3696:1998

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SIST EN ISO 3696:1998

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SIST EN ISO 3696:1998

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SIST EN ISO 3696:1998
IS0
INTERNATIONAL STANDARD
3696
First edition
1987-04- 15
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INTERNATIONAL ORGANIZATION FOR STANDARDIZATION
ORGANISATION INTERNATIONALE DE NORMALISATION
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Water for analytical laboratory use - Specification and
test methods
Eau pour laboratoire ;i usage analytique - Spkification et mhthodes d ’essai
Reference number
IS0 3696 : 1987 (E)

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SIST EN ISO 3696:1998
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, govern-
mental 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. They are approved in accordance with IS0 procedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 3696 was prepared by Technical Committee ISO/TC 47,
Chemistry.
Users should note that all International Standards undergo revision from time to time
and that any reference made herein to any other International Standard implies its
latest edition, unless otherwise stated.
International Organization for Standardization, 1987
0
Printed in Switzerland

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SIST EN ISO 3696:1998
IS0 3696 : 1987 (E)
INTERNATIONAL STANDARD
Water for analytical laboratory use - Specification and
test methods
1 Scope and field of application 0,2 pm to remove particulate matter or redistillation from a
fused silica apparatus).
This International Standard specifies the requirements and cor-
responding test methods for three grades of water for
laboratory use for the analysis of inorganic chemicals.
Grade 2
It is not applicable to water for organic trace analysis, to water
Very low in inorganic, organic or colloidal contaminants and
for the analysis of surface active agents, or to water for
suitable for sensitive analytical purposes, including atomic
biological or medical analysis.
absorption spectrometry (AAS) and the determination of con-
stituents in trace quantities; should be produced, for example,
NOTE - For some purposes (for example for certain analytical
by multiple distillation, or by deionization or reverse osmosis
methods or for tests in which the water is required to be sterile or
followed by distillation.
pyrogen-free or of specified surface tension), additional specific tests
and further purification or other treatment may be necessary.
Grade 3
2 Description
Suitable for most laboratory wet chemistry work and prepara-
The material shall be a clear, colourless liquid as assessed by
tion of reagents solutions; should be produced, for example, by
visual inspection.
single distillation, by deionization, or by reverse osmosis.
Unless otherwise specified, it should be used for ordinary
analytical work.
3 Classification
NOTE - It is assumed that the initial feed stock water is potable and
reasonably pure. If it is heavily contaminated in any respect, some
This International Standard covers three grades of water as
pretreatment may be necessary.
follows :
Grade 1
Essentially free from dissolved or colloidal ionic and organic
contaminants and suitable for the most stringent analytical 4 Requirements
requirements including those of high-performance liquid
The material shall comply with the appropriate requirements of
chromatography; should be produced by further treatment of
the table. Testing for compliance shall be carried out by means
grade 2 water (for example reverse osmosis or deionization
of the methods specified in clause 7.
followed by filtration through a membrane filter of pore size
1

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SIST EN ISO 3696:1998
IS0 3696 : 1987 (El
Table - Requirements
Test
Grade 1 Grade 2 Grade 3
Parameter
method
pH value at 25 OC Not applicable Not applicable 5,0 to 7,5 Sub-clause 7.1
inclusive range (see note 1) (see note I)
0,Ol
Electrical conductivity OJ %5 Sub-clause 7.2
(see note 2) (see note 2)
mS/m at 25 OC, max.
Oxidizable matter Not applicable 0,08 Sub-clause 7.3
0,4
(see note 3)
Oxygen (0) content
mg/l, max
0,001 0,Ol Not specified Sub-clause 7.4
Absorbance at 254 nm and 1 cm optical path length,
absorbance units, max.
Not applicable 1 2
Residue after evaporation Sub-clause 7.5
on heating at 110 OC (see note 3)
mg/kg, max.
0,Ol 0,02 Not specified Sub-clause 7.6
Silica (SiO2) content
mg/l, max.
NOTES
containers or absorption of atmospheric carbon dioxide and of
any other impurities present in the laboratory atmosphere.
1 Because of the difficulties associated with measurement of the pH
value of high-purity water, and the doubtful significance of the value
For this reason, the storage of grade 1 and grade 2 water is not
obtained, limits for the pH of grade 1 and grade 2 water have not been
recommended, the water being prepared, as required, for
specified.
immediate use.
2 The values of conductivity for grade 1 and grade 2 water apply to
freshly prepared water; during storage, it is possible for contaminants
Nevertheless, grade 2 water may be prepared in reasonable
such as atmospheric carbon dioxide and alkalis from glass containers
quantity and stored in suitable, inert, clean, airtight, full con-
to be dissolved, leading to changes in conductivity.
tainers which have been thoroughly pre-rinsed with water of
3 A limit for oxidizable matter and residue after evaporation for
similar grade.
grade 1 water is not specified because of the difficulty of testing for
compliance at this level of purity. The quality of grade 1 water is,
The storage of grade 3 water presents little problem, but the
however, assured by compliance with the other requirements and by
containers and storage conditions should be the same as those
its method of preparation.
used for the storage of grade 2 water.
It is recommended that any storage container be reserved
5 Sampling
exclusively for the storage of a particular grade of water.
A representative sample of the material of not less than 2 litres
shall be taken from the bulk for the purpose of examination in
accordance with this specification.
7 Methods of test
NOTE - This sample is not used for measurements of conductivity on
grade 1 and grade 2 water (see 7.2.2.1).
It is essential that the determinations specified in this
clause are carried out in a dust-free, pure atmosphere and
The sample shall be placed in a suitable, clean, airtight con-
that suitable precautions are taken to prevent any con-
tainer, reserved solely for water samples, which shall be of such
tamination of the sample and test portions.
a size that it is completely filled by the sample. Care shall be
taken to avoid the risk of contaminating the contents in any
way.
7.1 Measurement of pH
Aged containers (i.e. containers boiled for at least 2 h in a solu-
7.1.1 Apparatus
tion of hydrochloric acid, c(HCI) = 1 mol/l, then twice for 1 h
in distilled water) made of borosilicate glass can be used as well
Ordinary laboratory apparatus and
as suitable inert plastics containers (for example polyethylene
or polypropylene), but it is essential to establish that the sample
pH-meter, fitted with a glass measuring electrode and an
is unaffected by storage therein, particularly in respect of
Ag/AgCI reference electrode.
oxidizable matter and absorbance.
7.1.2 Procedure
6 Storage
Calibrate the pH-meter (7.1.1) in accordance with the manufac-
turer ’s instructions, using buffer solutions having pH values
Contamination of water during storage may arise principally
covering the range 4,0 to 8,0.
from dissolution of soluble constituents from glass or plastics
2

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