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BRITISH STANDARD

Laboratory glassware — Single-volume pipettes (ISO 648:2008)

ICS 17.060

NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW

BS EN ISO 648:2008

BS EN ISO 648:2008

National foreword This British Standard is the UK implementation of EN ISO 648:2008. It supersedes BS1583:1986 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee LBI/36/1, General and volumetric, glass and plastics apparatus. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2008 © BSI 2008

ISBN 978 0 580 58559 3

Amendments/corrigenda issued since publication Date

Comments

EUROPEAN STANDARD

EN ISO 648

NORME EUROPÉENNE EUROPÄISCHE NORM

October 2008

ICS 17.060

English Version

Laboratory glassware - Single-volume pipettes (ISO 648:2008) Verrerie de laboratoire - Pipettes à un volume (ISO 648:2008)

Laborgeräte aus Glas - Vollpipetten (ISO 648:2008)

This European Standard was approved by CEN on 4 October 2008. 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 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 Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: rue de Stassart, 36

© 2008 CEN

All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

B-1050 Brussels

Ref. No. EN ISO 648:2008: E

BS EN ISO 648:2008

EN ISO 648:2008 (E)

Foreword This document (EN ISO 648:2008) has been prepared by Technical Committee ISO/TC 48 "Laboratory glassware and related apparatus" in collaboration with Technical Committee CEN/TC 332 “Laboratory equipment”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2009, and conflicting national standards shall be withdrawn at the latest by April 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. 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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 648:2008 has been approved by CEN as a EN ISO 648:2008 without any modification.

3

BS EN ISO 648:2008 ISO 648:2008(E)

Contents

Page

Foreword............................................................................................................................................................ iv 1

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

2

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

3

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

4 4.1 4.2 4.3

Basis of adjustment.............................................................................................................................. 2 Unit of volume ....................................................................................................................................... 2 Delivery volume .................................................................................................................................... 2 Reference temperature......................................................................................................................... 2

5 5.1 5.2

Types and classes of accuracy ........................................................................................................... 2 Classes of accuracy ............................................................................................................................. 2 Types of single-volume pipette ........................................................................................................... 2

6

Maximum permissible errors............................................................................................................... 3

7 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8

Construction.......................................................................................................................................... 3 Material .................................................................................................................................................. 3 Shape ..................................................................................................................................................... 3 Bulb ........................................................................................................................................................ 3 Dimensions............................................................................................................................................ 4 Top of pipette ........................................................................................................................................ 5 Delivery jet ............................................................................................................................................. 5 Delivery time.......................................................................................................................................... 5 Waiting time........................................................................................................................................... 6

8

Graduation line(s) ................................................................................................................................. 6

9

Setting of the meniscus ....................................................................................................................... 6

10

Marking .................................................................................................................................................. 6

11

Visibility of graduation lines, figures and inscriptions..................................................................... 7

12

Colour coding........................................................................................................................................ 7

Bibliography ....................................................................................................................................................... 8

© ISO 2008 – All rights reserved

iii

BS EN ISO 648:2008 ISO 648:2008(E)

Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 648 was prepared by Technical Committee ISO/TC 48, Laboratory equipment, Subcommittee SC 6, Laboratory and volumetric ware. This second edition cancels and replaces the first edition (ISO 648:1977), which has been technically revised to incorporate the following modifications: a)

single-volume pipettes with two marks have been added;

b)

the waiting time for pipettes Class AS has been reduced to 5 s;

c)

dimensions have been modified;

d)

the nominal volume of 200 ml has been deleted.

iv

© ISO 2008 – All rights reserved

BS EN ISO 648:2008

INTERNATIONAL STANDARD

ISO 648:2008(E)

Laboratory glassware — Single-volume pipettes

1

Scope

This International Standard specifies metrological and constructional requirements for volumetric pipettes with one mark (total delivery) and for volumetric pipettes with two marks, both of which are adequate for general laboratory purposes. The details specified are in conformity with the principles of design and construction of volumetric glassware given in ISO 384. NOTE

2

For graduated pipettes, see ISO 835. For piston-operated pipettes, see ISO 8655-2.

Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 384:1978, Laboratory glassware — Principles of design and construction of volumetric glassware ISO 719, Glass — Hydrolytic resistance of glass grains at 98 °C — Method of test and classification ISO 1769, Laboratory glassware — Pipettes — Colour coding ISO 3696, Water for analytical laboratory use — Specification and test methods

3

Terms and definitions

For the purposes of this document, the following terms and definitions apply. 3.1 delivery volume volume of liquid discharged from the pipette NOTE Due to retention of liquid on the inner surface of the volumetric instrument, the volume of liquid delivered is not identical with the volume of liquid contained by the volumetric instrument.

3.2 delivery time time required for the descent of the liquid meniscus from the graduation line to the point at which the meniscus appears to come to rest in the jet for one-mark pipettes and from the upper graduation line to the lower graduation line for two-mark pipettes 3.3 waiting time time to be observed after apparent completion of the liquid delivery of the volumetric instrument NOTE

A waiting time applies for Class AS single-volume pipettes (see Clause 5 and 7.8).

© ISO 2008 – All rights reserved

1

BS EN ISO 648:2008 ISO 648:2008(E)

4 4.1

Basis of adjustment Unit of volume

The unit of volume shall be the millilitre (ml), which is equivalent to one cubic centimetre (cm 3).

4.2

Delivery volume

Single-volume pipettes shall be adjusted with water of grade 3 quality, in accordance with to ISO 3696, to deliver their nominal volume (Ex). The delivery should be under gravity and unrestricted. For details, see 7.7 and 7.8.

4.3

Reference temperature

The standard reference temperature, i.e. the temperature at which the pipette is intended to deliver its nominal volume, shall be 20 °C. When the pipette is required for use in a country which has adopted a standard reference temperature of 27 °C (the alternative recommended in ISO 384 for tropical use), this figure shall be substituted for 20 °C.

5 5.1

Types and classes of accuracy Classes of accuracy

Two classes of accuracy are specified: ⎯

Class A and AS for the higher grade;

⎯

Class B for the lower grade.

5.2

Types of single-volume pipette

The following two types of single-volume pipettes are specified: ⎯

those for which no waiting time is specified (Classes A and B);

⎯

those for which a waiting time of 5 s is specified (Class AS).

2

© ISO 2008 – All rights reserved

BS EN ISO 648:2008 ISO 648:2008(E)

6

Maximum permissible errors

Maximum permissible errors in the delivered volume shall not exceed the limits specified in Table 1. Table 1 — Nominal volumes and maximum permissible errors Nominal volume

Maximum permissible error Class A and AS

Class B

ml

± ml

± ml

0,5

0,005

0,010

1

0,008

0,015

2

0,010

0,02

5

0,015

0,03

10

0,02

0,04

20

0,03

0,06

25

0,03

0,06

50

0,05

0,10

100

0,08

0,15

The relationships between maximum permissible error and nominal volume, as well as between maximum permissible error and meniscus diameter as given in ISO 384:1978, Annex A and Annex B, shall be observed. For the maximum permissible errors of single-volume pipettes with intermediate nominal volumes between those given in Table 1, the value for the nearest nominal volume shall apply. If the intermediate volume is exactly halfway between those given in Table 1, the value for the next greater nominal volume shall apply.

7 7.1

Construction Material

Single-volume pipettes shall be manufactured from glass of chemical resistance and thermal properties at least to HGB3 in accordance with ISO 719, shall be as free as possible from visible defects and reasonably free from internal stress.

7.2

Shape

Pipettes of 0,5 ml nominal volume shall consist of a straight tube with a jet at the lower end. Pipettes of nominal volume 1 ml and 2 ml may be of similar straight tube pattern or may alternatively be of bulb pattern, as described herein for the larger sizes. All larger pipettes shall consist of a bulb with suction and delivery tubes, the three portions being straight and coaxial.

7.3

Bulb

The main portion of the bulb shall be cylindrical, except that 1 ml and 2 ml nominal-volume pipettes may have an oval bulb if desired. The two ends of the bulb shall merge gradually into the suction and delivery tubes, the junctions being of tapered formation to facilitate drainage.

© ISO 2008 – All rights reserved

3

BS EN ISO 648:2008 ISO 648:2008(E)

7.4

Dimensions

Single-volume pipettes shall comply with the dimensional requirements shown in Tables 2, 3 and 4. Table 2 — Dimensions Dimensions

Nominal volume

mm

ml 0,5

1

2

5

10

20

25

50

100

Overall length

max.

300

325

350

410

450

520

530

550

600

Internal diameter at the graduation line

max.

2,5

3,5

4,5

4,5

5

5,5

5,5

6

7,5

min.

—

150

150

150

160

170

170

170

170

min.

—

110

125

145

160

210

220

230

240

±1

—

5

6

6,5

7

7

7

8

9

max.

—

9

9

12

16

22

24

30

38

max.

5

6

7

—

—

—

—

—

—

Length of suction tube ⎯

valid only for bulb pattern pipettes

Length of delivery tube ⎯

valid only for bulb pattern pipettes

External diameter of delivery tube ⎯

valid only for bulb pattern pipettes

External diameter of bulb ⎯ valid only for bulb pattern pipettes External diameter of tube ⎯

valid only for straight pattern pipettes

Table 3 — Dimensions applying to all nominal volumes of one-mark pipettes Dimension

Size mm

Distance of graduation line from top of pipette Distance from graduation line to top of

bulba

Distance from graduation line to tip of jet ⎯

valid only for straight pattern pipettes

min.

100

min.

10

min.

110

Wall thickness ⎯

bulb pattern pipettes

min.

0,6

⎯

straight pattern pipettes

min.

0,8

a

Top of bulb relates to the point at which the suction tube begins to expand into the bulb.

4

© ISO 2008 – All rights reserved

BS EN ISO 648:2008 ISO 648:2008(E)

Table 4 — Dimensions applying to all nominal volumes of two-mark pipettes Dimension

Size mm

Distance of upper graduation line from top of pipette

min.

100

Distance from upper graduation line to top of bulba

min.

10

min.

110

Distance from lower graduation line to bottom of bulb

min.

20

Distance from lower graduation line to tip of jet

min.

30

Distance from upper graduation line to tip of jet ⎯

valid only for straight pattern pipettes a

Wall thickness ⎯

bulb pattern pipettes

min.

0,6

⎯

straight pattern pipettes

min.

0,8

a

Top of bulb and bottom of bulb relate to the points at which the suction tube and the delivery tube begin to expand into the bulb.

7.5

Top of pipette

The top of the single-volume pipette shall lie in a plane at right angles to the axis of the pipette and shall be free from any blemishes which might interfere with the required accurate control by a mechanical device or by the finger in setting the meniscus. The end may be lightly fire-polished or smoothly ground with a slight bevel on the outside.

7.6

Delivery jet

The lower end of the pipette shall terminate either in a delivery jet having a smooth and gradual taper or in a capillary end, both without sudden constriction at the orifice which could give rise to turbulent outflow. The end of the jet may be finished by grinding or machine tooling and may be fire-polished.

7.7

Delivery time

For testing of the delivery time, the clean pipette shall be held in a vertical position and filled with de-ionized water to a few millimetres above the (upper) graduation line; the falling meniscus shall then be set to this line. Any drop adhering to the jet of the pipette shall be removed by bringing the surface of a glass vessel into contact with the tip of the jet. Delivery shall then be made into another glass vessel which is slightly inclined so that the tip of the jet is in contact with the inside of the vessel, but without movement of one against the other throughout the delivery period. For one-mark pipettes, delivery shall be made from the graduation line down to the jet of the pipette. For two-mark pipettes, delivery shall be made from the upper graduation line down to the lower graduation line. IMPORTANT — It is important that a glass receiving vessel be used. Capillary effects influencing the delivery time depend considerably on the material down which the water runs.

© ISO 2008 – All rights reserved

5

BS EN ISO 648:2008 ISO 648:2008(E)

The delivery time thus determined, in seconds, shall be within the limits specified in Table 5. Table 5 — Delivery times in seconds Nominal volume

0,5

1

2

5

10

20

25

50

100

ml Class A

min. max.

10 20

10 20

10 25

15 30

15 40

25 50

25 50

30 60

40 60

Class AS

min. max.

6 10

7 11

7 11

9 13

11 15

12 16

15 20

20 25

25 30

Class B

min. max.

4 20

5 20

5 25

7 30

8 40

9 50

10 50

13 60

25 60

max.

2

2

2

3

3

4

4

5

5

Maximum permissible difference between observed and marked delivery times

7.8

Waiting time

The waiting time for Class AS pipettes shall be 5 s and shall be marked on the pipette.

8

Graduation line(s)

The graduation line(s) shall be (a) clean, permanent, uniform line(s) completely encircling the tube, although a gap, not exceeding 10 % of the circumference, may be permitted. The line(s) shall lie in a plane at right angles to the longitudinal axis of the pipette. The line(s) thickness shall not exceed 0,4 mm or one half of the limit of volumetric error, whichever is smaller (see ISO 384). Dimensions limiting the position(s) of the graduation line(s) on the pipette are included in Tables 3 and 4.

9

Setting of the meniscus

Setting of the meniscus shall be performed according to ISO 384:1978, 5.4.

10 Marking 10.1 The following shall be marked on each single-volume pipette: a)

a number indicating the nominal volume and the symbol “ml” or the symbol “cm3” to indicate the unit in terms of which the pipette is adjusted;

b)

the inscription “20 °C” to indicate the reference temperature; where the reference temperature is 27 °C, this value shall be substituted for 20 °C;

c)

the letters “Ex” to indicate that the pipette has been adjusted to deliver its indicated nominal volume;

d)

the inscription “A”, “AS” or “B” to indicate the class of accuracy for which the pipette has been adjusted;

e)

the waiting time in the form: “Ex + 5 s”, when appropriate;

f)

the manufacturer's and/or supplier's name or mark.

6

© ISO 2008 – All rights reserved

BS EN ISO 648:2008 ISO 648:2008(E)

It is recommended to mark single-volume pipettes complying with this International Standard with the inscription “ISO 648”. 10.2 If required for certification purposes, the delivery time, in seconds, shall be marked on Class A and Class AS single-volume pipettes intended for official verification or certification. 10.3 The maximum permissible error according to Table 1 may be marked on all pipettes, for example by the inscription “± ... ml”.

11 Visibility of graduation lines, figures and inscriptions All figures, graduation lines and inscriptions shall be permanent, and of such size and form as to be clearly legible under usual conditions of use. NOTE

The permanence of marking can be assessed by the test methods specified in ISO 4794.

12 Colour coding If colour coding is used on single-volume pipettes, it shall comply with the requirements of ISO 1769.

© ISO 2008 – All rights reserved

7

BS EN ISO 648:2008 ISO 648:2008(E)

Bibliography

[1]

ISO 835, Laboratory glassware — Graduated pipettes

[2]

ISO 4794, Laboratory glassware — Methods for assessing the chemical resistance of enamels used for colour coding and colour marking

[3]

ISO 8655-2, Piston-operated volumetric apparatus — Part 2: Piston pipettes

8

© ISO 2008 – All rights reserved

BS EN ISO 648:2008

BS EN ISO 648:2008

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