FprEN ISO 8655-8

Piston-operated volumetric apparatus - Part 8: Photometric reference measurement procedure for the determination of volume (ISO/FDIS 8655-8:2021)

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).

Volumenmessgeräte mit Hubkolben - Teil 8: Photometrisches Referenzprüfverfahren zur Bestimmung des Volumens (ISO/FDIS 8655-8:2021)

Dieses Dokument 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 5 000 µl 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.

Appareils volumétriques à piston - Partie 8: Méthode photométrique de mesurage de référence pour la détermination du volume (ISO/FDIS 8655-8:2021)

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/DIS 8655-8:2020)

General Information

• Status: Not Published
• ICS: 17.060 - Measurement of volume, mass, density, viscosity
• ICS: 71.040.20 - Laboratory ware and related apparatus
• Technical Committee: CEN/TC 332 - Laboratory equipment
• Drafting Committee: CEN/TC 332/WG 1 - Glass and plastics devices including volumetric instruments
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Due Date: 13-Feb-2022
• Completion Date: 13-Feb-2022
• Ref Project: kSIST FprEN ISO 8655-8:2020 - Piston-operated volumetric apparatus - Part 8: Photometric reference measurement procedure for the determination of volume (ISO/DIS 8655-8:2020)

Standards Content (sample)

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
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Published in Switzerland
ii © ISO 2020 – All rights reserved
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oSIST prEN ISO 8655-8:2020
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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.
© ISO 2020 – All rights reserved v
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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.

vi © ISO 2020 – All rights reserved
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oSIST prEN ISO 8655-8:2020
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
Photometric repeatability at A = 0,0 AU 0,000 05 AU
Photometric repeatability at A = 0,5 AU 0,000 05 AU
Photometric repeatability at A = 1,0 AU 0,000 10 AU
Photometric repeatability at A = 1,5 AU 0,000 15 AU
Center wavelength reproducibility 0,025 nm
Bandwidth reproducibility 0,050 nm
Reproducibility of cuvette attenuance 0,000 10 AU

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.

Wavelength and bandwidth repeatability applies to instruments where wavelength and bandwidth are adjustable. It

does not apply to fixed-wavelength interference filter instruments.

Cuvette attenuance reproducibility applies to the spectrophotometer and cuvette tested together. An example is given

in ISO/TR 16153.
Applicable when use of ND glass standard is specified by the manufacturer.
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Table 1 (continued)
Parameter Requirement
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

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.

Wavelength and bandwidth repeatability applies to instruments where wavelength and bandwidth are adjustable. It

does not apply to fixed-wavelength interference filter instruments.

Cuvette attenuance reproducibility applies to the spectrophotometer and cuvette tested together. An example is given

in ISO/TR 16153.
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)
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
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
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

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
...