Piston-operated volumetric apparatus - Part 2: Pipettes (ISO 8655-2:2022)

This document specifies
—    metrological requirements,
—    maximum permissible errors,
—    requirements for marking and
—    information to be provided for users,
for air-displacement (type A) and positive displacement (type D) single-channel and multi-channel pipettes, complete with their selected tip(s) and any other essential, consumable parts, designed to deliver the selected volume (Ex).

Volumenmessgeräte mit Hubkolben - Teil 2: Pipetten (ISO 8655-2:2022)

Dieses Dokument trifft Festlegungen hinsichtlich
- metrologischer Anforderungen,
- Fehlergrenzen,
- Anforderungen an die Kennzeichnung, und
- Benutzerinformation
von Pipetten mit Luftpolster (Form A) und von Direktverdrängerpipetten (Form D); er gilt für Einkanal- und Mehrkanalpipetten, die auf das gewählte Volumen (Ex) justiert sind, vollständig mit ihren ausgewählten Pipettenspitzen und anderen wichtigen Verbrauchsteilen.

Appareils volumétriques à piston - Partie 2: Pipettes (ISO 8655-2:2022)

Le présent document spécifie:
—    les exigences métrologiques;
—    les erreurs maximales tolérées;
—    les exigences relatives au marquage; et
—    les informations à fournir aux utilisateurs;
pour les pipettes monocanal et multicanaux à déplacement d’air (type A) et à déplacement positif (type D), équipées de leur(s) cône(s) sélectionné(s) et de toutes les autres parties essentielles à usage unique, conçues pour distribuer le volume sélectionné (Ex).

Volumetrične naprave, delujoče na bat - 2. del: Pipete (ISO/DIS 8655-2:2020)

General Information

Status
Published
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
11-May-2022
Completion Date
11-May-2022

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SLOVENSKI STANDARD
oSIST prEN ISO 8655-2:2020
01-oktober-2020
Volumetrične naprave, delujoče na bat - 2. del: Pipete (ISO/DIS 8655-2:2020)
Piston-operated volumetric apparatus - Part 2: Pipettes (ISO/DIS 8655-2:2020)
Volumenmessgeräte mit Hubkolben - Teil 2: Pipetten (ISO/DIS 8655-2:2020)
Appareils volumétriques à piston - Partie 2: Pipettes (ISO/DIS 8655-2:2020)
Ta slovenski standard je istoveten z: prEN ISO 8655-2
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 8655-2:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 8655-2:2020
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oSIST prEN ISO 8655-2:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 8655-2
ISO/TC 48 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-07-29 2020-10-21
Piston-operated volumetric apparatus —
Part 2:
Pipettes
Appareils volumétriques à piston —
Partie 2: Pipettes
ICS: 17.060
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 8655-2:2020(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 8655-2:2020
ISO/DIS 8655-2:2020(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 8655-2:2020
ISO/DIS 8655-2:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle of operation ..................................................................................................................................................................................... 2

5 Adjustment ................................................................................................................................................................................................................. 2

5.1 Basis of adjustment ............................................................................................................................................................................. 2

5.2 Initial adjustment ................................................................................................................................................................................. 2

5.3 Subsequent adjustment ................................................................................................................................................................... 2

5.4 Adjustment for other liquid properties ............................................................................................................................. 2

6 Design .............................................................................................................................................................................................................................. 3

6.1 Types of pipette ...................................................................................................................................................................................... 3

6.2 Transfer of hand warmth ............................................................................................................................................................... 4

7 Pipette tips .................................................................................................................................................................................................................. 4

7.1 ............................................................................................................................................................................................................................. 4

7.1.1 General...................................................................................................................................................................................... 4

7.1.2 Air-displacement pipette tips ............................................................................................................................... 4

7.1.3 Positive-displacement pipette tips ................................................................................................................... 4

8 Type, designation ................................................................................................................................................................................................. 5

9 Metrological performance requirements ................................................................................................................................... 5

9.1 General ........................................................................................................................................................................................................... 5

9.1.1 Reference test ..................................................................................................................................................................... 5

9.1.2 Routine testing................................................................................................................................................................... 5

9.2 Fixed-volume pipettes of types A and D1 ........................................................................................................................ 5

9.3 Fixed-volume pipettes of type D2 ........................................................................................................................................... 6

9.4 Variable-volume pipettes of types A, D1 and D2 ....................................................................................................... 6

9.5 Multi-channel pipettes ..................................................................................................................................................................... 6

9.6 Calculation of maximum permissible errors for volumes not listed in Tables 1, 2 and 3 ...... 6

9.7 Pipette tips .................................................................................................................................................................................................. 9

10 Marking .......................................................................................................................................................................................................................... 9

10.1 Pipettes .......................................................................................................................................................................................................... 9

10.2 Pipette tips .................................................................................................................................................................................................. 9

Annex A (normative) Information to be provided with pipettes and tips ..................................................................10

Annex B (informative) Possible sources of error for air displacement pipettes .................................................11

Annex C (informative) Electronic motorized air displacement pipettes and method

for testing in multi-dispensing mode ...........................................................................................................................................13

Bibliography .............................................................................................................................................................................................................................15

© ISO 2020 – All rights reserved iii
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oSIST prEN ISO 8655-2:2020
ISO/DIS 8655-2:2020(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 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.

This second edition cancels and replaces the first edition (ISO 8655-2:2002 and ISO 8655-2:2002/Cor

1:2008), which has been technically revised.
The main changes compared to the previous edition are as follows:
— ISO 8655-7, ISO 8655-8 and ISO 8655-9 have been added as normative references;

— Metrological Performance requirements for pipette tips have been further specified;

— Tables 1 and 2 have been revised;
— A new Table 3 has been introduced;
— A new informative Annex C for motorized pipettes has been introduced;
— Annex A has been revised.
A list of all parts in the ISO 8655 series can be found on the ISO website.

Annex A forms a normative part of this part of ISO 8655. Annex B and Annex C are for information only.

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.
iv © ISO 2020 – All rights reserved
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Introduction
ISO 8655 addresses the needs of:

— manufacturers, as a basis for quality control including, where appropriate, the issuance of

manufacturers’ declarations;

— calibration laboratories, test houses, users of the equipment and other bodies as a basis for

independent calibration, verification and routine checking.

The tests specified in the ISO 8655 series are intended to be carried out by trained personnel.

© ISO 2020 – All rights reserved v
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oSIST prEN ISO 8655-2:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 8655-2:2020(E)
Piston-operated volumetric apparatus —
Part 2:
Pipettes
1 Scope
This part of ISO 8655 specifies
— metrological requirements,
— maximum permissible errors,
— requirements for marking and
— information to be provided for users,

for air-displacement (type A) and positive displacement (type D) single-channel and multi-channel

pipettes, complete with their selected tip(s) and any other essential, consumable parts, designed to

deliver the selected volume (Ex).

NOTE General requirements and definitions of terms for piston-operated volumetric apparatus are given

in ISO 8655-1. The gravimetric reference measurement procedure for the determination of volume is given

in ISO 8655-6. The photometric reference measurement procedure for the determination of volume is given

in ISO 8655-8. Alternative methods for the determination of volume are described in ISO 8655-7. For safety

requirements of electrically powered pipettes, see regional or national safety standards.

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 3696:1991, 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 8655-6:2020, Piston-operated volumetric apparatus — Part 6: Gravimetric reference measurement

procedure for the determination of volume

ISO/DIS 8655-7:2020, Piston operated volumetric apparatus — Part 7: Alternative test methods for the

determination of volume

ISO/DIS 8655-8:2020, Piston-operated volumetric apparatus — Part 8: Photometric reference

measurement procedure for the determination of volume
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/DIS 8655-1:2020 apply.

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
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— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle of operation

Pipettes are used to accurately handle preselected volumes. The tip is attached to the pipette. Pipettes

are typically operated using forward pipetting. Using forward pipetting, with the piston positioned at

the lower aspiration limit, the tip is dipped into the liquid to be dispensed. When moved to the upper

aspiration limit, the piston aspirates the liquid. The liquid volume to be dispensed is then expelled by

depressing or sliding the piston between the volume-defining limits. Some air-displacement pipettes

(see 6.1, Type A) have an extra air volume which can be used to expel the last drop of liquid.

See also Figure 1.

Manufacturers' instruction manuals should contain detailed and specific information about the proper

operation of pipettes.
5 Adjustment
5.1 Basis of adjustment

A pipette shall be adjusted for the delivery (Ex) of its nominal volume (or selected volume, in the case of

a variable-volume model).

For countries that have adopted the standard reference temperature of 20 °C, the adjustment shall be

for the temperature 20 °C, a relative air humidity of 50 % and a barometric pressure of 101,3 kPa, when

handling grade 3 water as specified in ISO 3696.

For those countries that have adopted a standard reference temperature of 27 °C, the adjustment shall

be for the temperature 27 °C, a relative air humidity of 50 % and a barometric pressure of 101,3 kPa,

when handling grade 3 water as specified in ISO 3696.
5.2 Initial adjustment
A pipette shall be provided with an initial adjustment.
5.3 Subsequent adjustment

Some pipettes have provision for adjustment when, for example, it is found in a routine check that

the volume delivered is not within specification. Such adjustment shall be made according to the

manufacturer's instructions and by reference to a measurement procedure according to ISO 8655-6,

ISO 8655-7 or ISO 8655-8.

Any pipette so adjusted shall have clear, visible evidence that the initial adjustment has been modified.

This information shall also be recorded.
5.4 Adjustment for other liquid properties

Some pipettes are designed to have their factory pre-set adjustment altered by the user so that they will

dispense their specified volume when used with liquids with physical properties differing from those of

water (see Annex B for details). In such cases, the design shall prevent unintentional readjustment. Such

adjustment shall be made according to the manufacturer's instructions or by reference to the selected

test procedure from ISO 8655-7 and the modifications made.

If the pipette is readjusted, it shall be clearly and unequivocally indicated on the outside of the pipette

that readjustment has been affected. The outside of the pipette shall be marked with the name of the

liquid and the adjusted volume range. This information shall be documented appropriately.

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6 Design
6.1 Types of pipette
A pipette may be designed as follows:

— fixed volume, designed by the manufacturer to dispense only its nominal volume, e.g. 100 μl;

— variable volume, designed by the manufacturer to dispense volumes selectable by the user within

its specified useable volume range, e.g. between 10 μl and 100 μl.
The piston may

— either have a body of air contained between the piston and the surface of the liquid (air displacement

– Type A); or

— be in direct contact with the surface of the liquid (positive or direct displacement – Type D).

In the case of the type D pipette, either the plunger or the capillary, or both may be reusable (Type D1)

or disposable (Type D2). See Figure 1 for details.
Type D Type A
Positive (direct) displacement Air displacement
a) Single-channel pipettes b) Multi-channel pipette
Figure 1 — Pipettes
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6.2 Transfer of hand warmth

The construction of pipettes and the materials used for their manufacture shall be chosen in such a way

that any heat transmitted from the user's hand to the apparatus during periods of use is minimized.

NOTE Transfer of hand warmth will appear as a systematic drift of results (the delivered volume decreases

over time) during a series of deliveries.
7 Pipette tips
7.1
7.1.1 General

7.1.1.1 The dispensing orifice of the tip shall be shaped in such a way that consistent dispensing of

the liquid to be measured is achieved. When the tip is touched against the wall of a vessel in successive

operations, any amount of liquid remaining in or around the dispensing orifice of the tip shall be

consistent.

7.1.1.2 In the case of sterilisable pipette tips the sterilisation procedures indicated as appropriate

by the manufacturer in user information or on packaging (see Annex A) shall not negatively affect the

metrological characteristics of the tips such as shape, seal and wettability.

NOTE This requirement can be assessed by comparing errors of measurement using tips which have and

have not been sterilised.
7.1.2 Air-displacement pipette tips

7.1.2.1 Air-displacement pipette tips shall be disposable parts, usually made of plastic, which fit on the

tip cone of the pipette and prevent the instrument from contact with the aspirated liquid.

7.1.2.2 Tips for air-displacement shall be fitted in accordance with the pipette supplier's instructions

to form a good seal between the tip and the tip cone of the pipette.

NOTE Variability of amount of externally retained liquid or an incomplete seal will contribute to poor

precision.

Pipette tips made of plastic for pipettes with air interface are designed for single use. They shall not be

cleaned for reuse as their met
...

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