SIST EN ISO 8655-8:2022

SLOVENSKI STANDARD
01-julij-2022
Volumetrične naprave, delujoče na bat - 8. del: Postopek fotometričnega
referenčnega merjenja za določanje prostornine (ISO 8655-8:2022)
Piston-operated volumetric apparatus - Part 8: Photometric reference measurement
procedure for the determination of volume (ISO 8655-8:2022)
Volumenmessgeräte mit Hubkolben - Teil 8: Photometrisches Referenzprüfverfahren zur
Bestimmung des Volumens (ISO 8655-8:2022)
Appareils volumétriques à piston - Partie 8: Mode opératoire de mesure photométrique
de référence pour la détermination de volumes (ISO 8655-8:2022)
Ta slovenski standard je istoveten z: EN ISO 8655-8:2022
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
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 8655-8
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2022
EUROPÄISCHE NORM
ICS 17.060; 71.040.20
English Version
Piston-operated volumetric apparatus - Part 8:
Photometric reference measurement procedure for the
determination of volume (ISO 8655-8:2022)
Appareils volumétriques à piston - Partie 8: Mode Volumenmessgeräte mit Hubkolben - Teil 8:
opératoire de mesure photométrique de référence Photometrisches Referenzprüfverfahren zur
pour la détermination de volumes (ISO 8655-8:2022) Bestimmung des Volumens (ISO 8655-8:2022)
This European Standard was approved by CEN on 13 February 2022.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8655-8:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 8655-8:2022) has been prepared by Technical Committee ISO/TC 48
"Laboratory equipment" 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 November 2022, and conflicting national standards
shall be withdrawn at the latest by November 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 8655-8:2022 has been approved by CEN as EN ISO 8655-8:2022 without any
modification.
INTERNATIONAL ISO
STANDARD 8655-8
First edition
2022-04
Piston-operated volumetric
apparatus —
Part 8:
Photometric reference measurement
procedure for the determination of
volume
Appareils volumétriques à piston —
Partie 8: Mode opératoire de mesure photométrique de référence
pour la détermination de volumes
Reference number
ISO 8655-8:2022(E)
ISO 8655-8:2022(E)
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 8655-8:2022(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
5 Test equipment .2
5.1 General . 2
5.2 Spectrophotometer . 2
5.3 Cuvette and mixer . . 2
5.4 Measuring devices . 3
5.5 Equipment used for solution preparation . 3
5.6 Balances . 3
5.7 Density meter . 4
5.8 pH meter . 4
6 Reagents . 4
6.1 General requirements . 4
6.2 Water . 4
6.3 Buffer solution . 4
6.4 Copper(II) chloride solution . 4
6.5 Ponceau S solutions . 4
6.6 Calibrator solutions . 5
6.7 Stability of solutions . 6
6.7.1 General . 6
6.7.2 Preservatives . 6
6.7.3 Light sensitivity . 6
6.7.4 Storage temperature . 6
7 Test conditions .6
7.1 General . 6
7.2 Test room . 6
7.3 Evaporation . 7
8 Procedure .7
8.1 General . 7
8.1.1 Summary . 7
8.1.2 Test conditions . 7
8.1.3 Test volume . 7
8.1.4 Number of measurements per volume to be tested . 8
8.2 System calibration . 8
8.2.1 General . 8
8.2.2 System calibration procedure . 8
8.2.3 Previous calibration . 8
8.3 Photometric procedure . 8
8.3.1 Preparation of cuvettes . 8
8.3.2 Zero of the spectrophotometer . 9
8.3.3 Starting absorbances . 9
8.3.4 Dispensing of test liquids . . . 9
8.3.5 Absorbance of the chromophore mixture. 9
8.3.6 Calculation of the delivered test volume . 9
8.4 Preparation . 9
8.5 Single-channel air displacement pipettes (in accordance with ISO 8655-2) . 10
8.5.1 General . 10
iii
ISO 8655-8:2022(E)
8.5.2 Test cycle . 10
8.6 Multi-channel pipettes (in accordance with ISO 8655-2) . 11
8.7 Positive displacement pipettes (in accordance with ISO 8655-2) . 11
8.8 Burettes (in accordance with ISO 8655-3) . 11
8.9 Dispensers (in accordance with ISO 8655-5) .12
8.10 Syringes (in accordance with ISO 8655-9) .12
8.10.1 General .12
8.10.2 Test cycle . 12
9 Evaluation .13
9.1 Calculation of volume . 13
9.1.1 Calibration constant . 13
9.1.2 Volume of test liquid .13
9.1.3 Temperature correction . 14
9.1.4 Mean volume . 14
9.2 Systematic error of measurement . 14
9.3 Random error of measurement . 15
9.4 Uncertainty of measurement .15
10 Reporting of results .15
Annex A (normative) Calculation of volumes from balance readings .17
Bibliography .18
iv
ISO 8655-8:2022(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 48, Laboratory equipment, in collaboration
with the European Committee for Standardization (CEN) Technical Committee CEN/TC 332, Laboratory
equipment, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
A list of all parts in the ISO 8655 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
ISO 8655-8:2022(E)
Introduction
The ISO 8655 series addresses the needs of:
— manufacturers, as a basis for quality control including, where appropriate, the issuance of
manufacturer’s declarations;
— calibration laboratories, test houses, users of the equipment and other bodies as a basis for
independent calibration, testing, verification, and routine tests.
The tests specified in the ISO 8655 series are intended to be carried out by trained personnel.
vi
INTERNATIONAL STANDARD ISO 8655-8:2022(E)
Piston-operated volumetric apparatus —
Part 8:
Photometric reference measurement procedure for the
determination of volume
1 Scope
This document specifies the photometric reference measurement procedure for the determination
of volume of piston-operated volumetric apparatus (POVA). The procedure is applicable to complete
systems comprising the basic apparatus with a maximum nominal volume of 5 000 µl and all parts
selected for use with the apparatus, disposable or reusable, involved in the measurement by delivery
(Ex).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 8655-1:2022, Piston-operated volumetric apparatus — Part 1: Terminology, general requirements and
user recommendations
ISO 8655-2, Piston-operated volumetric apparatus — Part 2: Pipettes
ISO 8655-3, Piston-operated volumetric apparatus — Part 3: Burettes
ISO 8655-5, Piston-operated volumetric apparatus — Part 5: Dispensers
ISO 8655-9, Piston-operated volumetric apparatus — Part 9: Manually operated precision laboratory
syringes
ISO/IEC Guide 2, Standardization and related activities — General vocabulary
ISO/IEC Guide 99:2007, International vocabulary of metrology — Basic and general concepts and
associated terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in in ISO 8655-1, ISO/IEC Guide 2,
and ISO/IEC Guide 99 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
ISO 8655-8:2022(E)
4 General requirements
When performing calibrations according to the reference measurement procedure described in
this document, all provisions and requirements of this document shall be followed or exceeded (e.g.,
performing 30 instead of 10 replicates per volume). If one or more of those requirements is not followed,
conformity to this document shall not be claimed.
5 Test equipment
5.1 General
Measurement equipment for spectrophotometry, weighing, temperature, density, pH, humidity, and
barometric pressure shall be traceable to the international system of units (SI) and shall meet the
uncertainty requirements of this document.
NOTE An example of the calculation of the expanded uncertainty of the photometric reference procedure is
[1]
given in ISO/TR 16153 .
5.2 Spectrophotometer
The visible range spectrophotometer shall meet the performance requirements specified in Table 1 at
520 nm and 730 nm.
Table 1 — Performance requirements of the spectrophotometric system
Parameter Requirement
a
Photometric repeatability at A = 0,0 AU 0,000 05 AU
a
Photometric repeatability at A = 0,5 AU 0,000 05 AU
a
Photometric repeatability at A = 1,0 AU 0,000 10 AU
a
Photometric repeatability at A = 1,5 AU 0,000 15 AU
b
Centre wavelength reproducibility 0,025 nm
b
Bandwidth reproducibility 0,050 nm
c
Reproducibility of cuvette attenuance 0,000 10 AU
d
ND glass calibration standards
Uncertainty at A = 0,5 AU 0,001 5 AU
Uncertainty at A = 1,0 AU 0,002 5 AU
Uncertainty at A = 1,5 AU 0,003 0 AU
a
Repeatability to be measured as standard deviation using the same reading procedures, settings and conditions as
are used during the photometric volume determination. Adjusting integration time (sample averaging time), bandpass (slit
width), and the number of replicate readings are acceptable means of improving the spectrophotometer’s repeatability.
b
Wavelength and bandwidth reproducibility applies to instruments where wavelength and bandwidth are adjustable. It
does not apply to fixed-wavelength interference filter instruments.
c
Cuvette attenuance reproducibility applies to the spectrophotometer and cuvette tested together. An example is given
[1]
in ISO/TR 16153 .
d
Applicable when use of ND glass standard is specified by the manufacturer.
5.3 Cuvette and mixer
The cuvette shall be made of a material with at least 99 % internal optical transmittance at 520 nm and
730 nm. The cuvette shall have an optical path length of 20 mm ± 2 mm. If multiple cuvettes are used,
each cuvette shall have a path length within ± 0,2 mm of the chosen nominal.
A mixing mechanism shall be fitted to the cuvette holder of the spectrophotometer, such that the
cuvette’s contents can be mixed while the cuvette remains seated in the spectrophotometer. Mixing
ISO 8655-8:2022(E)
shall ensure that the liquid contents are mixed to within 0,010 % of complete mixing. Mixing speed
shall be sufficient to wash down dye solution deposited on the cuvette side wall.
Mixing mechanisms, such as orbital mixing, a glass-covered magnetic stir bar or a PTFE-covered
(polytetrafluoroethylene, PTFE) magnetic stir bar may be used and shall be verified to meet this
requirement.
NOTE Complete mixing is achieved when re-mixing and re-measuring the absorbance produces a systematic
change no larger than the required value.
5.4 Measuring devices
The minimum requirements for each relevant measuring device are specified in Table 2.
Table 2 — Minimum requirements for measuring devices
Device Resolution Expanded uncertainty of meas-
urement (k = 2)
Thermometer for liquids 0,01 °C 0,2 °C
Thermometer for room air 0,1 °C 0,3 °C
Hygrometer 1 % relative humidity 5 % relative humidity
Barometer 0,1 kPa 1 kPa
Timing device 1 s not applicable
NOTE Acceptable means of measuring the temperature of a solution in a cuvette include a thermistor bead
probe immersed in the solution within the cuvette; a suitable contact thermometer on the outside of the cuvette;
or a suitable infrared thermometer.
5.5 Equipment used for solution preparation
Solutions shall be prepared by gravimetric or volumetric means.
The liquid components of solutions may be weighed using balances, which shall meet the requirements
of Table 3.
For volumetric preparations, class A glassware meeting the maximum permissible errors for narrow
neck flasks of ISO 1042 shall be used.
5.6 Balances
Balances used for accurate weighing of dry reagents, preparation of calibrator solutions, and filling of
cuvettes shall meet the requirements specified in Table 3.
Table 3 — Minimum requirements for balances
Minimum mass to be Resolution Repeatability Expanded uncertainty in
a
weighed use (k = 2)
(d) (s)
g mg mg mg
1,0 0,01 0,02 0,04
10 0,1 0,2 0,4
100 1 2 4
1 000 10 20 40
a
Uncertainty in use is determined according to Reference [2] at the minimum mass listed in the table.
Weighing results for liquids shall be corrected for density, temperature and air buoyancy when
determining volume, see Annex A.
ISO 8655-8:2022(E)
5.7 Density meter
Densities of the chromophore solutions shall be measured for each lot of solutions using a temperature-
controlled density meter with an uncertainty of 0,000 05 g/ml (k = 2) or better.
5.8 pH meter
The pH meter is used for the preparation of the solutions in 6.3, 6.4, 6.5, and 6.6. It shall be calibrated
with reference buffer solutions over a range from pH 4 to pH 7 including pH 6,00 according to
manufacturer’s instructions. A reference material having a certified value in the range of pH 6,00 ± 0,05
and an uncertainty (k = 2) of 0,02 pH units, or better is required for comparison.
6 Reagents
6.1 General requirements
All components used in the preparation of reagent solutions shall be of at least 99 % analytical purity
unless otherwise stated.
NaOH (CAS No. 1310-73-2) and HCl (CAS No. 7647-01-0) solutions may be used for adjustment of pH.
The measured pH value of the reagent solutions in 6.3, 6.4, 6.5 and 6.6 shall be compared to the pH 6
certified reference material in 5.8.
6.2 Water
Water (CAS No. 7732-18-5) used for preparing chromophore solutions shall comply with Grade 1 in
accordance with ISO 3696:1987.
6.3 Buffer solution
Dissolve 4,08 g of potassium hydrogen phthalate (CAS No. 877-24-7) and 3,81 g of tetrasodium
ethylenediaminetetraacetic acid dihydrate (EDTA, CAS No. 10378-23-1) per litre of water, adjust to pH
6,0 ± 0,1, and filter through a 0,2 µm filter.
6.4 Copper(II) chloride solution
Dissolve 1,12 g/l of copper(II) chloride dihydrate (CuCl ·2H O) (CAS No. 10125-13-0) in the phthalate/
2 2
EDTA buffer and adjust to pH 6,0 ± 0,1. Filter the resulting solution through a 0,2 µm filter.
6.5 Ponceau S solutions
Dissolve Ponceau S (CAS No. 6226-79-5) in water, adjust to pH 6,0 ± 0,1, and then filter the dye solution
through a 0,2 µm filter. Table 4 indicates the amount of Ponceau S dye (which can contain up to 15 %
water) per litre of solution. These Pon
...