Piston-operated volumetric apparatus - Part 8: Photometric reference measurement procedure for the determination of volume (ISO 8655-8:2022)

This part of ISO 8655 specifies a photometric reference measurement procedure for the determination
of volume of piston-operated volumetric apparatus. The tests are applicable to complete systems
comprising the basic apparatus (with a maximum nominal volume of 10 mL) and all parts selected for
use with the apparatus, disposable or reusable, involved in the measurement by uptake (In) or delivery
(Ex).
NOTE General requirements and definitions of terms for piston-operated volumetric apparatus are
given in ISO 8655-1. For the metrological requirements, maximum permissible errors, requirements for
marking and information to be provided for users for piston-operated volumetric apparatus, see ISO
8655-2 for pipettes, see ISO 8655-3 for burettes, see ISO 8655-4 for dilutors, see ISO 8655-5 for
dispensers, and see ISO 8655-9 for manually operated precision laboratory syringes. The gravimetric
reference measurement procedure for the determination of volume of piston-operated volumetric
apparatus is given in ISO 8655-6. Alternative methods for the determination of volume are given in ISO
8655-7.

Volumenmessgeräte mit Hubkolben - Teil 8: Photometrisches Referenzprüfverfahren zur Bestimmung des Volumens (ISO 8655-8:2022)

Dieser Teil von ISO 8655 legt das photometrische Referenzmessverfahren zur Bestimmung des Volumens von Volumenmessgeräten mit HubkolbenN1) fest. Das Verfahren gilt für vollständige Gerätesysteme, bestehend aus dem Grundgerät mit einem Nennvolumen von höchstens 5 ml und allen für die Verwendung ausgewählten Zubehörteilen, die mehrfach verwendbar oder für den einmaligen Gebrauch bestimmt und an der Messung auf Ablauf (Ex) beteiligt sind.
ANMERKUNG Allgemeine Anforderungen und Begriffsdefinitionen für Kolbenhubgeräte sind in ISO 8655-1 festgelegt. Hinsichtlich der messtechnischen Anforderungen, der Fehlergrenzen sowie der Anforderungen an Kennzeichnung und Nutzerinformation siehe ISO 8655-2 für Pipetten, ISO 8655-3 für Büretten, ISO 8655-4 für Dilutoren, ISO 8655-5 für Dispenser und ISO 8655-9 für manuell betätigte Präzisionslaborspritzen. Das gravimetrische Referenzverfahren für die Volumenbestimmung von Kolbenhubgeräten ist in ISO 8655-6 angegeben. Alternative Messverfahren für die Volumenbestimmung werden in ISO 8655-7 aufgeführt.

Appareils volumétriques à piston - Partie 8: Mode opératoire de mesure photométrique de référence pour la détermination de volumes (ISO 8655-8:2022)

Le présent document spécifie un mode opératoire de mesure photométrique de référence pour la détermination du volume des appareils volumétriques à piston (AVAP). Le mode opératoire est applicable à des systèmes complets comprenant l’appareil de base présentant un volume nominal maximal de 5 000 µl et toutes les parties sélectionnées pour être utilisées avec l’appareil, à usage unique ou réutilisables, utilisés dans la mesure de la distribution (Ex).

Volumetrične naprave, delujoče na bat - 8. del: Postopek fotometričnega referenčnega merjenja za določanje prostornine (ISO 8655-8:2022)

Ta del standarda ISO 8655 določa postopek fotometričnega referenčnega merjenja za določanje prostornine volumetrične naprave, delujoče na bat. Preskusi se uporabljajo za celotne sisteme, ki jih sestavljajo osnovna naprava (z največjo nazivno prostornino 10 ml) in vsi deli, izbrani za uporabo skupaj z napravo, namenjeni enkratni ali večkratni uporabi, ki se uporabljajo pri merjenju z zajemanjem (In) ali dovajanjem (Ex).
OPOMBA: Splošne zahteve in definicije izrazov za volumetrične naprave, delujoče na bat, so podane v standardu ISO 8655-1. Za meroslovne zahteve, največje dopustne pogreške, zahteve za označevanje in informacije, predvidene za uporabnike za volumetrične naprave, delujoče na bat, glej standard ISO 8655-2 za pipete, standard ISO 8655-3 za birete, standard ISO 8655-4 za dilutorje, standard ISO 8655-5 za dozirnike in standard ISO 8655-9 za natančne laboratorijske brizge z ročnim upravljanjem. Gravimetrični referenčni postopek merjenja za določanje prostornine volumetrične naprave, delujoče na bat, je podan v standardu ISO 8655-6. Nadomestne metode za določanje prostornine so podane v standardu ISO 8655-7.

General Information

Status
Published
Public Enquiry End Date
20-Oct-2020
Publication Date
22-May-2022
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
19-May-2022
Due Date
24-Jul-2022
Completion Date
23-May-2022

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SLOVENSKI STANDARD
SIST EN ISO 8655-8:2022
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
SIST EN ISO 8655-8:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 8655-8:2022

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SIST EN ISO 8655-8:2022


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.

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SIST EN ISO 8655-8:2022
EN ISO 8655-8:2022 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 8655-8:2022
EN ISO 8655-8:2022 (E)
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.


3

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SIST EN ISO 8655-8:2022

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SIST EN ISO 8655-8:2022
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 2022

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SIST EN ISO 8655-8:2022
ISO 8655-8:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© 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 2022 – All rights reserved

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SIST EN ISO 8655-8:2022
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 2022 – All rights reserved

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SIST EN ISO 8655-8:2022
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
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SIST EN ISO 8655-8:2022
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
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SIST EN ISO 8655-8:2022
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
  © ISO 2022 – All rights reserved

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SIST EN ISO 8655-8:2022
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/
1
© ISO 2022 – All rights reserved

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SIST EN ISO 8655-8:2022
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
2
  © ISO 2022 – All rights reserved

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SIST EN ISO 8655-8:2022
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.
...

SLOVENSKI STANDARD
oSIST prEN ISO 8655-8:2020
01-oktober-2020
Volumetrične naprave, delujoče na bat - 8. del: Postopek fotometričnega
referenčnega merjenja za določanje prostornine (ISO/DIS 8655-8:2020)
Piston-operated volumetric apparatus - Part 8: Photometric reference measurement
procedure for the determination of volume (ISO/DIS 8655-8:2020)
Volumenmessgeräte mit Hubkolben - Teil 8: Photometrisches Referenzprüfverfahren zur
Bestimmung des Volumens (ISO/DIS 8655-8:2020)
Appareils volumétriques à piston - Partie 8: Titre manque
Ta slovenski standard je istoveten z: prEN ISO 8655-8
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
oSIST prEN ISO 8655-8:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 8655-8:2020

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oSIST prEN ISO 8655-8:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 8655-8
ISO/TC 48 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-07-29 2020-10-21
Piston-operated volumetric apparatus —
Part 8:
Photometric reference measurement procedure for the
determination of volume
ICS: 17.060; 71.040.20
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 8655-8:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020

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oSIST prEN ISO 8655-8:2020
ISO/DIS 8655-8:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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 2020 – All rights reserved

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oSIST prEN ISO 8655-8:2020
ISO/DIS 8655-8:2020(E)

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General requirements . 2
5 Test equipment. 2
5.1 General . 2
5.2 Spectrophotometer . 2
5.3 Cuvette and mixer . 3
5.4 Thermometers, hygrometer, and barometer . 3
5.5 Volumetric glassware . 3
5.6 Balances . 4
5.7 Density meter . 4
5.8 pH meter . 4
6 Test liquids . 4
6.1 Water . 4
6.2 Potassium hydrogen phthalate/EDTA buffer . 4
6.3 Copper(II) chloride solution . 5
6.4 Ponceau S stock solutions. 5
6.5 Calibrator solutions . 5
6.6 Stability of solutions . 6
6.6.1 Preservatives . 6
6.6.2 Light sensitivity . . 6
6.6.3 Storage temperature . 6
7 Test Conditions . 7
7.1 General . 7
7.2 Test room . 7
7.3 Evaporation . 7
8 Procedure. 7
8.1 General . 7
8.1.1 Test volume. 7
8.1.2 Number of measurements per volume to be tested . 8
8.2 System calibration . 8
8.2.1 System calibration procedure . 8
8.2.2 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 samples . . 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
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
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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 .19
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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 on 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 the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 48, Laboratory Equipment, Working
Group WG 4, Piston- operated instruments.
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.
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Introduction
ISO 8655 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, certification, and routine checking.
The tests specified in the ISO 8655 series are intended to be carried out by trained personnel.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 8655-8:2020(E)
Piston-operated volumetric apparatus —
Part 8:
Photometric reference measurement procedure for the
determination of volume
1 Scope
This part of ISO 8655 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 ml and all parts selected
for use with the apparatus, disposable or reusable, involved in the measurement by delivery (Ex).
NOTE General requirements and definitions of terms for piston-operated volumetric apparatus are given
in ISO 8655-1. For the metrological requirements, maximum permissible errors, requirements for marking
and information to be provided for users of piston-operated volumetric apparatus, see ISO 8655-2 for pipettes,
see ISO 8655-3 for burettes, see ISO 8655-4 for dilutors, see ISO 8655-5 for dispensers, and see ISO 8655-9 for
manually operated precision laboratory syringes. The gravimetric reference procedure for the determination of
volume of piston-operated volumetric apparatus is given in ISO 8655-6. Alternative measurement procedures for
the determination of volume are given in ISO 8655-7.
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 3696, Water for analytical laboratory use — Specification and test methods
ISO/DIS 8655-1:2020, Piston-operated volumetric apparatus — Part 1: Terminology, general requirements
and user recommendations
ISO/DIS 8655-2:2020, Piston-operated volumetric apparatus — Part 2: Pipettes
ISO/DIS 8655-3:2020, Piston-operated volumetric apparatus — Part 3: Burettes
ISO/DIS 8655-5:2020, Piston-operated volumetric apparatus — Part 5: Dispensers
ISO/DIS 8655-9:2020, Piston-operated volumetric apparatus — Part 9: Manually operated precision
laboratory syringes
ISO/TR 16153, Piston-operated volumetric instruments — Determination of uncertainty for volume
measurements made using the photometric method
ISO/IEC Guide 2, Standardization and related activities — General vocabulary
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
me a s ur ement (GUM: 1995)
ISO/IEC Guide 98-4, Uncertainty of measurement — Part 4: Role of measurement uncertainty in conformity
assessment
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
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3 Terms and definitions
For the purposes of this document, the terms and definitions given in in ISO/DIS 8655-1:2020,
ISO/IEC Guide 2, and ISO/IEC Guide 99 apply.
Note 1 to entry Further definitions and explanations of chemical terms can be found in the IUPAC Compendium
of Chemical Terminology.[1]
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 General requirements
When performing calibrations according to the reference measurement procedure described in this
standard, all provisions and requirements of this standard shall be followed. If one or more of those
requirements is not followed, conformity to ISO 8655-8 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 standard.
NOTE An example of the calculation of the expanded uncertainty of the photometric reference procedure is
given in ISO/TR 16153.
5.2 Spectrophotometer
The visible range spectrophotometer shall meet the performance requirements according to 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
Center wavelength reproducibility 0,025 nm
b
Bandwidth reproducibility 0,050 nm
c
Reproducibility of cuvette attenuance 0,000 10 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 repeatability 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
in ISO/TR 16153.
d
Applicable when use of ND glass standard is specified by the manufacturer.
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Table 1 (continued)
Parameter Requirement
d
ND glass calibration standards 0,001 5
   Uncertainty at A = 0,5 AU 0,002 5
   Uncertainty at A = 1,0 AU 0,003 0
   Uncertainty at A = 1,5 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 repeatability 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
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
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
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 Thermometers, hygrometer, and barometer
The minimum requirements for each relevant measuring device are listed in Table 2.
Table 2 — Minimum requirements for measuring devices
Device Readability Expanded uncertainty of meas-
urement (k = 2)
a
Thermometer for liquids 0,02 °C 0,2 °C
Thermometer for room air 0,1 °C 0,2 °C
Hygrometer 1 % rel. humidity 5 % rel. humidity
Barometer 0,1 kPa 1 kPa
Timing device 1 s n/a
a
Thermometer for liquids shall have a repeatability of 0,05 °C or better.
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 Volumetric glassware
Solutions shall be prepared by volumetric or gravimetric means. For volumetric preparations, class A
flasks shall be used to bring solutions to the final volume.
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Alternatively, the liquid components of solutions may be weighed, in which case volumetric glassware
is not required.
5.6 Balances
Balances used for accurate weighing of dry reagents, preparation of calibrator solutions, and filling of
cuvettes shall meet the requirements according to Table 3.
Table 3 — Minimum requirements for balances
Minimum amount to be Readability (d) Repeatability (s) Expanded uncertainty in
a
weighed use (k = 2)
g mg mg mg
1,0 0,01 0,02 0,04
10 0,1 0,2 0,4
100 1 2 4
1000 10 20 40
a
Uncertainty in use is determined according to EURAMET cg-18 at the minimum weight listed in the Table [2].
Weighing results for liquids shall be corrected for density, temperature and air buoyancy when
determining volume (see Annex A).
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 6.2, 6.3, and 6.4. 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 Test liquids
All components used in the preparation of reagent solutions shall be of 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 6.2, 6.3, and 6.4 shall be compared to the pH 6 certified
reference material of Clause 5.8.
6.1 Water
Water (CAS No. 7732-18-5) used for preparing chromophore solutions shall comply with Grade 1 in
accordance with ISO 3696.
6.2 Potassium hydrogen phthalate/EDTA buffer
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.
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6.3 Copper(II) chloride solution
Dissolve 1,12 g/l of c
...

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