SIST EN ISO 8655-7:2006
(Main)Piston-operated volumetric apparatus - Part 7: Non-gravimetric methods for the assessment of equipment performance (ISO 8655-7:2005)
Piston-operated volumetric apparatus - Part 7: Non-gravimetric methods for the assessment of equipment performance (ISO 8655-7:2005)
This standard specifies the photometric and titrimetric determination of errors of measurement of piston-operated volumetric apparatus. The tests are applicable to complete systems comprising the basic apparatus and all parts selected for use with the apparatus, disposable or reusable, involved in the measurement by delivery process.These non-gravimetric test methods can be applied. as aids to quality assurance by the supplier, . as routine quality assurance and routine calibrations by the user, and. as routine and post-repair testing.The methods described in this part of ISO 8655 are not applicable as alternatives to the gravimetric reference test methods specified in ISO 8655-6, which gives the only method suitable as a basis for supplier's declarations or independent certification of conformity.NOTE 1 Metrological requirements for piston-operated volumetric apparatus, especially maximum permissible errors, are specified in ISO 8655-2 to ISO 8655- 5.NOTE 2 For conformity tests or type tests for declaration and certification of conformity, see the gravimetric reference test methods in ISO 8655-6.
Volumenmessgeräte mit Hubkolben - Teil 7: Nicht-gravimetrische Prüfverfahren zur Bewertung der Geräteeigenschaften (ISO 8655-7:2005)
Dieser Teil von ISO 8655 legt photometrische und titrimetrische Prüfverfahren zur Bestimmung der Messabweichung von Volumenmessgeräten mit Hubkolben fest. Die Prüfungen gelten für vollständige Gerätesysteme, bestehend aus dem Grundgerät und aller für die Verwendung ausgewählten Zubehörteile, die mehrfach verwendbar oder für den einmaligen Gebrauch bestimmt sein können; die Dosierung erfolgt durch Abgabevorgänge.
Diese nicht-gravimetrischen Prüfverfahren können für folgende Zwecke angewendet werden:
- Unterstützung bei der Qualitätssicherung des Anbieters,
- routinemäßige Qualitätssicherung und Kalibrierung durch den Anwender,
- Wiederholungsprüfung und Prüfung nach Reparatur.
Die Prüfverfahren dieses Teils von ISO 8655 gelten nicht als Alternative zum gravimetrischen Prüfverfahren nach ISO 8655-6, wenn es um die Grundlage für Herstellererklärungen oder unabhängige Konformitätsbe-scheinigung geht; hierfür gilt nur das gravimetrische Referenzprüfverfahren nach ISO 8655-6.
ANMERKUNG 1 Messtechnische Anforderungen an Kolbenhubgeräte, insbesondere Fehlergrenzen, sind in ISO 8655-2 bis ISO 8655-5 festgelegt.
ANMERKUNG 2 Konformitätsprüfungen oder Baumusterprüfungen als Grundlage für Konformitätserklärungen und Konformitätsbescheinigungen sind im gravimetrischen Referenzprüfverfahren nach ISO 8655-6 festgelegt.
Appareils volumétriques a piston - Partie 7: Méthodes non gravimétriques pour l'estimation de la performance d'équipement (ISO 8655-7:2005)
L'ISO 8655-7:2005 spécifie la détermination photométrique et titrimétrique d'erreurs de mesure d'appareils volumétriques à piston. Les essais sont applicables à des systèmes complets comprenant l'appareil de base et toutes les parties sélectionnées pour être utilisées avec l'appareil, jetables ou réutilisables, utilisés dans la mesure du procédé de distribution.
Ces méthodes d'essai non gravimétriques peuvent être appliquées pour une aide à l'assurance qualité par le fournisseur, l'assurance qualité et l'étalonnage de routine par l'utilisateur, et les essais de routine et après réparations.
Les méthodes décrites dans l'ISO 8655-7:2005 ne sont pas des variantes de la méthode d'essai gravimétrique de référence spécifiée dans l'ISO 8655-6, qui est la seule méthode appropriée comme référence pour les déclarations des fournisseurs ou pour une certification de conformité indépendante.
Les exigences métrologiques relatives aux appareils volumétriques à piston, en particulier les limites d'erreurs tolérées, sont spécifiées de l'ISO 8655-2 à l'ISO 8655-5.
Pour les essais de conformité ou les essais de type destinés à la déclaration et à la certification de conformité, les méthodes d'essai gravimétriques de référence s'appliquent conformément à l'ISO 8655-6.
Volumetrične naprave, ki delujejo na bat - 7. del: Negravimetrične metode za ocenjevanje tehničnih karakteristik (ISO 8655-7:2005)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 8655-7:2006
01-februar-2006
9ROXPHWULþQHQDSUDYHNLGHOXMHMRQDEDWGHO 1HJUDYLPHWULþQHPHWRGH]D
RFHQMHYDQMHWHKQLþQLKNDUDNWHULVWLN ,62
Piston-operated volumetric apparatus - Part 7: Non-gravimetric methods for the
assessment of equipment performance (ISO 8655-7:2005)
Volumenmessgeräte mit Hubkolben - Teil 7: Nicht-gravimetrische Prüfverfahren zur
Bewertung der Geräteeigenschaften (ISO 8655-7:2005)
Appareils volumétriques a piston - Partie 7: Méthodes non gravimétriques pour
l'estimation de la performance d'équipement (ISO 8655-7:2005)
Ta slovenski standard je istoveten z: EN ISO 8655-7:2005
ICS:
17.060 Merjenje prostornine, mase, Measurement of volume,
gostote, viskoznosti mass, density, viscosity
71.040.20 Laboratorijska posoda in Laboratory ware and related
aparati apparatus
SIST EN ISO 8655-7:2006 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 8655-7:2006
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SIST EN ISO 8655-7:2006
EUROPEAN STANDARD
EN ISO 8655-7
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2005
ICS 17.060
English Version
Piston-operated volumetric apparatus - Part 7: Non-gravimetric
methods for the assessment of equipment performance (ISO
8655-7:2005)
Appareils volumétriques à piston - Partie 7: Méthodes non Volumenmessgeräte mit Hubkolben - Teil 7: Nicht-
gravimétriques pour l'estimation de la performance gravimetrische Prüfverfahren zur Bewertung der
d'équipement (ISO 8655-7:2005) Geräteeigenschaften (ISO 8655-7:2005)
This European Standard was approved by CEN on 13 August 2005.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8655-7:2005: E
worldwide for CEN national Members.
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SIST EN ISO 8655-7:2006
EN ISO 8655-7:2005 (E)
Foreword
This document (EN ISO 8655-7:2005) has been prepared by Technical Committee ISO/TC 48
"Laboratory glassware and related apparatus" in collaboration with Technical Committee
CEN/TC 332 "Laboratory equipment", the secretariat of which is held by DIN.
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 March 2006, and conflicting national
standards shall be withdrawn at the latest by March 2006.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 8655-7:2005 has been approved by CEN as EN ISO 8655-7:2005 without any
modifications.
2
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SIST EN ISO 8655-7:2006
INTERNATIONAL ISO
STANDARD 8655-7
First edition
2005-09-01
Piston-operated volumetric apparatus —
Part 7:
Non-gravimetric methods for the
assessment of equipment performance
Appareils volumétriques à piston —
Partie 7: Méthodes non gravimétriques pour l'estimation de la
performance d'équipement
Reference number
ISO 8655-7:2005(E)
©
ISO 2005
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(E)
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ii © ISO 2005 – All rights reserved
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Principle. 2
4.1 Photometric method. 2
4.2 Titrimetric method . 2
5 Reagents. 3
5.1 Reagents for photometric method. 3
5.2 Reagents for titrimetric method . 3
6 Apparatus . 4
6.1 Photometric method. 4
6.2 Titrimetric method . 4
7 Test conditions . 5
8 Procedure . 5
8.1 General. 5
8.2 Photometric method. 5
8.3 Titrimetric method . 5
9 Calculation. 6
10 Test report . 6
Annex A (informative) Example 1 for photometric test method . 7
Annex B (informative) Example 2 for photometric test method . 13
Annex C (informative) Example for titration test method. 17
Bibliography . 21
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(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 8655-7 was prepared by Technical Committee ISO/TC 48, Laboratory glassware and related apparatus,
Subcommittee SC 6, Laboratory and volumetric ware.
ISO 8655 consists of the following parts, under the general title Piston-operated volumetric apparatus:
Part 1: Terminology, general requirements and user recommendations
Part 2: Piston pipettes
Part 3: Piston burettes
Part 4: Dilutors
Part 5: Dispensers
Part 6: Gravimetric methods for the determination of measurement error
Part 7: Non-gravimetric methods for the assessment of equipment performance
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(E)
Introduction
The ISO 8655 series was developed in order to specify the differing types of piston-operated volumetric
apparatus and to provide a reference method and alternative test methods for verifying their characteristics
covering the volume range typically from:
the smallest hand-held pipetting devices, e.g. 1 µl, up to
the largest laboratory bench-standing volume dispensing instruments, e.g. 100 ml.
ISO 8655-1 provides general requirements and terminology. The detailed volumetric ranges for each type of
apparatus specified in the ISO 8655 series are indicated in the appropriate tables of maximum permissible
error, i.e. for piston pipettes (ISO 8655-2), for piston burettes (ISO 8655-3), for dilutors (ISO 8655-4) and for
dispensers (ISO 8655-5).
ISO 8655-6 is the reference method for type testing and conformity testing. It is gravimetric and contains
precise instructions designed to limit variation in procedure and thereby the potential for sources of error – a
necessity for type and conformity testing.
The photometric and titrimetric methods described in this part of ISO 8655, are deliberately given as outline
methods (see examples in the informative annexes), so that individual laboratories having their own
equipment available, and working to different uncertainty requirements, may adapt either these methods, or
the gravimetric method, accordingly. If the laboratories operate under ISO 9000 series regimes, or have
accreditation to ISO 17025, the individually-adapted methods are usually validated to give results equivalent
to those given by the gravimetric method specified in ISO 8655-6.
This part of ISO 8655 is applicable to the following types of testing:
of piston-operated volumetric apparatus for purposes other than type testing or the conformity testing
which is required prior to declarations or certification of conformity;
in user locations, where there may be no suitable balance or facilities to perform the reference method
given in ISO 8655-6, but which may have at their disposal a suitable photometer or automatic titrator.
As users have expressed the wish to have alternative tests available, the following observations are given to
help them select the most appropriate test methods for their purposes.
a) Gravimetric method: Uncertainty values can increase at volumes significantly below 1 µl, due to
increasing balance uncertainty, especially in low humidity areas (where there is increased risk of
evaporation) and due to the effects of static electricity. These effects are compensated for through the
careful design of the test method specified in ISO 8655-6, which applies to the volume ranges specified in
ISO 8655-2 to ISO 8655-5.
b) Photometric method: This may be the method of choice for laboratories having a UV/VIS photometer of
suitable wavelength and bandwidth. Uncertainty with this method tends to become lower as test volumes
decrease and can be further reduced if the volumes used in dilution steps for the preparation of
comparative standards use larger capacity Class A glassware (e.g. 100 ml of chromophore solution
diluted to 1 000 ml can lead to lower uncertainty than 10 ml diluted to 100 ml).
c) Titrimetric method: This may be the method of choice of a laboratory already having a titrator with the
properties specified in 6.2 and C.4.1. in Annex C. The method is most suited to the testing of piston-
operated volumetric apparatus working in the volume range above 500 µl. Again, uncertainty can be
reduced if larger capacity Class A volumetric apparatus and larger weights of solid reagents are used to
prepare standard solutions.
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(E)
If any of these methods is adapted, the expanded uncertainty of measurement needs to be calculated to
enable comparison with the reference method. In any case, users will determine that the uncertainty of the
chosen method is suitable for their intended purpose.
The tests specified in the ISO 8655 series are intended to be carried out by trained personnel.
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SIST EN ISO 8655-7:2006
INTERNATIONAL STANDARD ISO 8655-7:2005(E)
Piston-operated volumetric apparatus —
Part 7:
Non-gravimetric methods for the assessment of equipment
performance
WARNING — The use of this part of ISO 8655 may involve hazardous materials, operations and
equipment. This standard does not purport to address all the safety problems associated with its use.
It is the responsibility of the user of this part of ISO 8655 to establish appropriate safety and health
practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This part of ISO 8655 specifies the photometric and titrimetric determination of errors of measurement of
piston-operated volumetric apparatus. The tests are applicable to complete systems comprising the basic
apparatus and all parts selected for use with the apparatus, disposable or reusable, involved in the
measurement by delivery process.
These non-gravimetric test methods can be applied
as aids to quality assurance by the supplier,
as routine quality assurance and routine calibrations by the user, and
as routine and post-repair testing.
The methods described in this part of ISO 8655 are not applicable as alternatives to the gravimetric reference
test methods specified in ISO 8655-6, which gives the only method suitable as a basis for supplier's
declarations or independent certification of conformity.
NOTE 1 Metrological requirements for piston-operated volumetric apparatus, especially maximum permissible errors,
are specified in ISO 8655-2 to ISO 8655-5.
NOTE 2 For conformity tests or type tests for declaration and certification of conformity, see the gravimetric reference
test methods in ISO 8655-6.
2 Normative references
The following referenced documents are indispensable for the application 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 648, Laboratory glassware — One-mark pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(E)
ISO 8655-1, Piston-operated volumetric apparatus — Part 1: Terminology, general requirements and user
recommendations
ISO 8655-2, Piston-operated volumetric apparatus — Part 2: Piston pipettes
ISO 8655-3:2002, Piston-operated volumetric apparatus — Part 3: Piston burettes
ISO 8655-4, Piston-operated volumetric apparatus — Part 4: Dilutors
ISO 8655-5, Piston-operated volumetric apparatus — Part 5: Dispensers
ISO 8655-6:2002, Piston-operated volumetric apparatus — Part 6: Gravimetric methods for the determination
of measurement error
3 Terms and definitions
For the purposes of this part of ISO 8655, the terms and definitions given in ISO 8655-1 apply.
4 Principle
4.1 Photometric method
The photometric method of testing piston-operated volumetric apparatus relies upon the relationship between
the concentration of a chromophore in solution and its absorbance of light at a specified wavelength, as
described by the Beer-Lambert law. The method can use one of two procedures, depending on the needs of
the calibration. In both methods, the test volume of liquid to be measured is delivered by the piston-operated
volumetric apparatus under test into a known volume of liquid, and the degree of dilution is calculated from
photometric measurements.
The first method is suitable for test volumes > 20 % of the total volume. The total volume depends on the size
of the photometric measuring cell and shall be large enough to adequately fill the cell in the UV/VIS
photometer. In this method a known volume of solution is prepared having an absorbance near the upper end
of the working range of the photometer and its absorbance is measured. The piston-operated volumetric
apparatus being tested is used to add an unknown volume of diluent, e.g. water or buffer. The resulting
solution is mixed well and its absorbance is measured. The unknown volume delivered can be calculated from
the decrease in absorbance.
The second method is suitable for test volumes < 20 % of the total volume. In this method a known volume of
diluent is prepared. The piston-operated volumetric apparatus being tested is used to add an unknown volume
of a sample solution of chromophore having known absorbance. The resulting solution is mixed well and its
absorbance is measured. The unknown volume delivered is then calculated from the increase in absorbance.
Annex A and Annex B give examples for test procedure and calculation.
Other photometric methods can be used, the suitability of which has been validated for the intended purpose.
4.2 Titrimetric method
The titrimetric test method is suitable for testing volumes of piston-operated volumetric apparatus W 500 µl. In
general, any titration can be used, the suitability of which has been validated for the intended purpose.
For example, a potassium chloride (KCl) solution can be used as test liquid to be dispensed by the device
under test into an acidified receiver liquid. The resulting test solution is titrated with silver nitrate (AgNO )
3
solution. The equivalence point is determined by potentiometric detection, e.g. with a silver electrode.
If the device under test is a piston burette, known concentrations of potassium chloride in a receiver vessel
can be titrated potentiometrically with silver nitrate using the piston burette under test.
Annex C gives an example for the test procedure.
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(E)
5 Reagents
All components of reagent solutions shall be of recognized analytical composition and purity.
5.1 Reagents for photometric method
If stock solutions are to be stored for any length of time, they shall be tested for chemical stability, and
preservatives added, if needed, to prevent microbiological growth. If the reagents degrade when exposed to
light, they shall be stored suitably protected to prevent degradation.
NOTE Instability of reagents when exposed to light can be a major source of uncertainty and a determination of
degradation can be necessary.
5.1.1 Water, complying with grade 1 in accordance with ISO 3696.
5.1.2 Chromophore solution
The dispensing characteristics of the chromophore solution, which are influenced by material parameters such
as surface tension, density and viscosity, shall be as close as possible compared to those of water in order to
facilitate correlation between the photometric and the gravimetric test methods. The potential for adsorption of
the chromophore on the wall shall be considered. If a discrepancy between the dispensing properties of the
chromophore solution and water is noted during the correlation study of the method, that discrepancy shall be
included in the uncertainty analysis.
The chromophore chosen shall be completely soluble at the highest concentration required.
NOTE Suitable chromophores are 2,2-azino-di-[3-ethylbenzthiazoline sulfonate(6)] (ABTS, relative molecular mass
M = 547,7), potassium dichromate K Cr O , Ponceau S and Orange G. An example of a reagent system based on
r 2 2 7
Ponceau S is given in Annex A.
5.1.3 Reagent system
The reagent system, consisting of chromophore, diluent, preservative (if needed) and buffer (if needed) shall
be chosen with the following criteria in mind. In all cases the uncertainty of measurement due to the various
contributions, e.g. uncertainty of pH, shall be estimated and included in the uncertainty budget.
[1]
NOTE An example is given in ISO/TR 16153 .
The concentration against absorbance relationship for the reagent system shall be well documented in
literature or shall be determined by the user. The wavelength chosen for absorbance measurement shall be at
or near an absorbance maximum of the reagent system to minimize the effect of wavelength errors on results.
The reagent system shall either be independent of pH or be buffered to limit pH change to an acceptable
range established in the uncertainty budget.
The reagent system shall either be independent of temperature or the results shall be characterized and
compensated for temperature.
5.1.4 Reagent solutions, to be prepared in concentrations depending on the volumes to be tested.
5.2 Reagents for titrimetric method
If the titration of potassium chloride with silver nitrate is used as the titrimetric method, solutions in accordance
with 5.2.1 to 5.2.4 shall be used.
5.2.1 Water, complying with grade 1 in accordance with ISO 3696.
5.2.2 Nitric acid, c(HNO ) = 1 mol/l or sulfuric acid c(H SO ) = 0,5 mol/l.
3 2 4
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(E)
5.2.3 Potassium chloride standard solutions, c(KCl) = 1 mol/l, c(KCl) = 0,1 mol/l and c(KCl) = 0,01 mol/l.
5.2.4 Silver nitrate standard solution, c(AgNO ) = 0,1 mol/l.
3
The solution shall be stored protected from light.
6 Apparatus
All apparatus shall be chosen such that the required uncertainty of measurement can be obtained. An
[1]
example of the calculation of the expanded uncertainty of a photometric method is given in ISO/TR 16153 .
All equipment shall be traceable to international or national standards and be of suitable readability, accuracy,
reproducibility and stability, consistent with the required expanded uncertainty of measurement.
6.1 Photometric method
6.1.1 UV/VIS photometer, with adequate resolution, linearity, repeatability, bandpass, absorbance
accuracy and wavelength accuracy over the range of absorbances utilized in the method.
An example is given in A.4.1 and Table A.3.
6.1.2 Measuring cell, with suitable optical quality.
If its pathlength is not known with sufficient accuracy to meet the requirements of the expanded uncertainty,
then a second reagent with known concentrations and absorptivity can be used to enable calculation to
compensate for the pathlength's influence on results.
An example is given in A.4.2.
A ratiometric analysis can be applied to determine the unknown volume without reference to measuring cell
pathlength.
6.1.3 Thermometer
If results are temperature-dependent, the temperature of the solutions shall be measured using a thermometer
with uncertainty consistent with the expanded uncertainty of the measurement.
6.1.4 Volumetric glassware, Class A
Known volumes of diluent or reagent solutions may be prepared either by using Class A volumetric glassware,
or by weighing, in which case the densities of the solutions shall be known.
If piston-operated volumetric apparatus is used for preparation of solutions, it shall conform to the applicable
part of ISO 8655 (see Clause 2) and shall be calibrated in accordance with ISO 8655-6.
6.2 Titrimetric method
6.2.1 Complete titration equipment, comprising burette, e.g. in accordance with ISO 8655-3, and a
sensor system for detection of the equivalence point of the chosen titration.
6.2.2 Electrode
If the titration of potassium chloride with silver nitrate is used as the titrimetric method, a combined silver
electrode should be used for potentiometric indication of the equivalence point. The silver surface of the
electrode should, preferably, be coated with AgCl or Ag S (see C.4.2).
2
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SIST EN ISO 8655-7:2006
ISO 8655-7:2005(E)
6.2.3 Class A volumetric glassware, such as one-mark pipettes in accordance with ISO 648 and one-
mark volumetric flasks in accordance with ISO 1042.
If piston-operated volumetric apparatus is used for the preparation of solutions, it shall conform to the
applicable part of ISO 8655 (see Clause 2) and shall be calibrated in accordance with ISO 8655-6.
6.2.4 Analytical balance
If the standard solutions according to 5.2.3 and 5.2.4 are prepared by the user, an analytical balance with
appropriate performance, such as appropriate minimum mass, shall be used.
7 Test conditions
7.1 Test room and general conditions should be in accordance with 6.1 and 6.2 of ISO 8655-6:2002.
7.2 Testing volume and number of measurements per volume to be tested depend upon user requirements.
Guidance can be found in 7.1.1 and 7.1.2 of ISO 8655-6:2002.
8 Procedure
8.1 General
Perform the preparation of solutions and measurements at a stable temperature, preferably 20 °C.
Perform the testing in accordance with the general principles specified in 4.1 and 4.2, and in accordance with
the manufacturer's instructions for the equipment specified in 6.1 and 6.2.
8.2 Photometric method
Two detailed examples for the application of the photometric method, including calculation of the dispensed
testing volumes, are given in Annexes A and B. In the first example, a removable measuring cell (also known
as cuvette or vial) containing a known volume of diluent is placed into the UV/VIS photometer and the test
volume is dispensed into it while it is in the UV/VIS photometer. The absorbance of the mixture is read after
mixing.
In the second example (see Annex B), the test vo
...
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