ISO 13318-2:2001
(Main)Determination of particle size distribution by centrifugal liquid sedimentation methods — Part 2: Photocentrifuge method
Determination of particle size distribution by centrifugal liquid sedimentation methods — Part 2: Photocentrifuge method
Détermination de la distribution granulométrique par les méthodes de sédimentation centrifuge dans un liquide — Partie 2: Méthode photocentrifuge
Določevanje granulacije z metodami centrifugalne sedimentacije v tekočini - 2. del: Fotocentrifugalna metoda
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INTERNATIONAL ISO
STANDARD 13318-2
First edition
2001-12-01
Determination of particle size distribution
by centrifugal liquid sedimentation
methods —
Part 2:
Photocentrifuge method
Détermination de la distribution granulométrique par les méthodes de
sédimentation centrifuge dans un liquide —
Partie 2: Méthode photocentrifuge
Reference number
ISO 13318-2:2001(E)
©
ISO 2001
---------------------- Page: 1 ----------------------
ISO 13318-2:2001(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2001
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2001 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 13318-2:2001(E)
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative references.1
3 Terms, definitions and symbols.2
3.1 Terms and definitions .2
3.2 Symbols.2
4 Principle.2
5 Apparatus .3
6 Sampling.5
7 Preparation.5
7.1 Sample preparation .5
7.2 Temperature .5
7.3 Dispersion .5
8 Procedure .5
8.1 Line-start methods .5
8.2 Homogeneous technique.6
9 Tests in duplicate and validation .7
9.1 Tests in duplicate .7
9.2 Validation.7
10 Calculation of results .7
10.1 General.7
10.2 Calculation of particle size .7
10.3 Calculation of cumulative mass percentage .7
11 Reporting of results.8
Annex A (informative) Worked example .10
Annex B (informative) Extinction curve, example for titanium dioxide.14
Annex C (informative) Effect of radial dilution.15
© ISO 2001 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 13318-2:2001(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 3.
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 part of ISO 13318 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 13318-2 was prepared by Technical Committee ISO/TC 24, Sieves, sieving and other sizing methods,
Subcommittee SC 4, Sizing by methods other than sieving.
ISO 13318 consists of the following parts, under the general title Determination of particle size distribution by
centrifugal liquid sedimentation methods:
Part 1: General principles and guidelines
Part 2: Photocentrifuge method
Part 3: Centrifugal X-ray method
Annexes A to C of this part of ISO 13318 are for information only.
iv © ISO 2001 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 13318-2:2001(E)
Introduction
The sample suspension in a photocentrifuge may be contained in a cuvet or a disc. Sample concentration is
determined by changes in a light signal monitored at a known radius. The cuvet photocentrifuge can only be run in
the homogeneous mode whereas the disc photocentrifuge may be run in either the homogeneous or the line-start
mode. Some systems permit the coarse end of the distribution to be measured in a gravitational mode and the fine
end in the centrifugal mode. The use of light to determine particle size distribution requires a calibration factor to be
applied as the particle size approaches the wavelength of the light, due to the inapplicability of the laws of
geometric optics.
© ISO 2001 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 13318-2:2001(E)
Determination of particle size distribution by centrifugal liquid
sedimentation methods —
Part 2:
Photocentrifuge method
WARNING — This part of ISO 13318 may involve hazardous materials, operations and equipment. This part
of ISO 13318 does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user of this part of ISO 13318 to establish appropriate safety and health practices and
determine the applicability of the regulatory limitations prior to its use.
1 Scope
This part of ISO 13318 covers methods for determining the particle size distribution of particulate materials by
means of centrifugal sedimentation in a liquid. Solids concentrations are determined by the transmission of a light
beam. The resulting signal enables conversion to a particle size distribution.
The method of determining the particle size distribution described in this part of ISO 13318 is applicable to powders
that can be dispersed in liquids, powders that are present in slurry form and some emulsions. Typical particle size
range for analysis is from about 0,1 µm to 5 µm. The method is applicable to powders in which all particles have
the same density and comparable shapes and do not undergo chemical or physical change in the suspension
liquid. It is usually necessary that the particles have a density higher than that of the liquid.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 13318. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 13318 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 13318-1, Determination of particle size distribution by centrifugal liquid sedimentation methods — Part 1:
General principles and guidelines
ISO 14887, Sample preparation — Dispersing procedures for powders in liquids
© ISO 2001 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 13318-2:2001(E)
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this part of ISO 13318 the terms and definitions of ISO 13318-1 apply.
3.2 Symbols
For the purposes of this this part of ISO 13318 the symbols of ISO 13318-1 and the following apply:
D optical density
E extinction coefficient for a particle of diameter x
i i
G constant dependent upon the geometry of the system, the dimensions of the light beam and on the shape
of the particles
l transmission of the emergent light beam, at the time t, after the start of sedimentation
l transmission of the emergent light beam when no particles are present
0
M distance from rotation axis to measurement zone (mm)
n number of particles of diameter x in the beam
i i
R distance from rotation axis to centrifuge wall, inner disc radius (mm)
S distance from rotation axis to liquid-air interface of sample (mm)
x diameter of the smallest particle in the light beam (µm)
0
x diameter of the largest particle in the light beam i.e. the Stokes diameter (µm)
St
4 Principle
A stable, finely collimated beam of light passes through a spinning disc or cuvet and sedimenting sample and is
detected at a known radius. Light rays, typically from either a white light source (e.g. incandescent bulb) or a
monochromatic coherent source (e.g. laser), pass through the suspension and are detected by a photodiode or
photomultiplier. The disc photocentrifuge can be operated in the line-start or homogeneous mode whereas the
cuvet photocentrifuge can be operated only in the homogeneous mode. The signal of the light beam is monitored
over the analysis time. The mass percentage of sample present in the beam is determined by calculating the ratio
of the light transmission signal, by use of a clear dispersing liquid, to the light transmission signal with the sample
present.
In the line-start mode the disc initially contains clear fill liquid to give maximum light transmission. Then the sample
is injected as a thin layer on top of the spinning fill liquid and begins to settle outward radially. When the largest
particles present reach the light beam the light transmission decreases, returning to the original transmission value
when the smallest particle present passes through the beam. A buffer layer is usually injected over the fill liquid to
prevent suspension breaking through the interface in a phenomenon known as “streaming”.
2 © ISO 2001 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 13318-2:2001(E)
5 Apparatus
5.1 Disc photocentrifuge, with a chamber consisting of a hollow disc with an entry port coaxial with the axis of
rotation (see Figure 1).Typically this is mounted vertically, or at a small angle to the vertical, on to the shaft of an
-1 -1
electric motor with a digitally variable speed typically between 500 r⋅min and 15 000 r⋅min . A white light source
and detector assembly measures transmittance through the suspension as a function of time. The instrument can
be used in either a line-start or homogeneous mode. Extinction coefficient corrections need to be applied for the
breakdown in the laws of geometric optics for both line-start and homogeneous modes. Additionally a correction is
required for radial dilution effects when the homogeneous mode is used. Software is provided with commercial
equipment to convert the data directly into size distributions in the form of tables or graphs of cumulative mass
percentage versus particle size.
5.2 Cuvet photocentrifuge, in which the disc is replaced with a rectangular cell containing a homogeneous
suspension (see Figure 2). Corrections need to be made for both radial dilution and light scattering effects as
described in ISO 13318-1. Cuvet photocentrifuges can typically be run in both the gravitational and centrifugal
modes. Additionally, some systems may offer a gradient mode permitting the centrifuge to accelerate throughout
the analysis in order to reduce the measurement time.
5.3 Ancillary apparatus, consisting of:
dispersing vessel e.g. glass beaker or bottle, of appropriate dimensions;
flexible spatula;
-1
ultrasonic bath or probe, a bottle shaker or high speed mechanical stirrer capable of rotating at 500 r⋅min to
-1
1 000 r⋅min .
Key
1 Motor shaft
2 Spin fluid
3 Buffer layer
4 Suspension
5 Entry port
6 Polymethylmethacrylate disc
Figure 1 — Side view of the disc of a disc photocentrifuge
© ISO 2001 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 13318-2:2001(E)
Key
1 Motor
2 Motor control
3 Signal process
4 ADC
5 CPU
6 Date time
7 Analysis parameters
8 RPM
9 Key board
10 Printer
11 Analog interface
12 Computer interface
13 Photo sensor RPM
14 Centrifugal cell
15 Rotating disc
16 LED
17 Photocell (reference)
18 Photocell (sample)
19 Photocells
a
Synchro-signal (reference)
b
Analogue signal
c
Synchro-signal (sample)
Figure 2 — Schematic diagram of a typical cuvet photocentrifuge
4 © ISO 2001 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 13318-2:2001(E)
6 Sampling
For sampling see ISO 13318-1.
7 Preparation
7.1 Sample preparation
An analysis sample shall be prepared as described in ISO 13318-1. The volume and concentration required
depends upon the volume of the centrifuge disc (or cuvet), the sensitivity of the optical-electronic system and
whether the line-start (disc only) or homogeneous method is to be used. In general, lower concentrations are
required than for other sedimentation methods. A concentration typically less than 0,25 % m/v and providing an
attenuation preferably in the 20 % to 30 % range compared to the spin fluid without sample is required.
7.2 Temperature
The temperature of the spin fluid (line-start method) or suspension (homogeneous method) shall be determined
and recorded before and after analysis in accordance with ISO 13318-1. The liquid viscosity
...
SLOVENSKI STANDARD
SIST ISO 13318-2:2002
01-junij-2002
'RORþHYDQMHJUDQXODFLMH]PHWRGDPLFHQWULIXJDOQHVHGLPHQWDFLMHYWHNRþLQLGHO
)RWRFHQWULIXJDOQDPHWRGD
Determination of particle size distribution by centrifugal liquid sedimentation methods --
Part 2: Photocentrifuge method
Détermination de la distribution granulométrique par les méthodes de sédimentation
centrifuge dans un liquide -- Partie 2: Méthode photocentrifuge
Ta slovenski standard je istoveten z: ISO 13318-2:2001
ICS:
19.120 Analiza velikosti delcev. Particle size analysis. Sieving
Sejanje
SIST ISO 13318-2:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 13318-2:2002
---------------------- Page: 2 ----------------------
SIST ISO 13318-2:2002
INTERNATIONAL ISO
STANDARD 13318-2
First edition
2001-12-01
Determination of particle size distribution
by centrifugal liquid sedimentation
methods —
Part 2:
Photocentrifuge method
Détermination de la distribution granulométrique par les méthodes de
sédimentation centrifuge dans un liquide —
Partie 2: Méthode photocentrifuge
Reference number
ISO 13318-2:2001(E)
©
ISO 2001
---------------------- Page: 3 ----------------------
SIST ISO 13318-2:2002
ISO 13318-2:2001(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2001
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.ch
Web www.iso.ch
Printed in Switzerland
ii © ISO 2001 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 13318-2:2002
ISO 13318-2:2001(E)
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative references.1
3 Terms, definitions and symbols.2
3.1 Terms and definitions .2
3.2 Symbols.2
4 Principle.2
5 Apparatus .3
6 Sampling.5
7 Preparation.5
7.1 Sample preparation .5
7.2 Temperature .5
7.3 Dispersion .5
8 Procedure .5
8.1 Line-start methods .5
8.2 Homogeneous technique.6
9 Tests in duplicate and validation .7
9.1 Tests in duplicate .7
9.2 Validation.7
10 Calculation of results .7
10.1 General.7
10.2 Calculation of particle size .7
10.3 Calculation of cumulative mass percentage .7
11 Reporting of results.8
Annex A (informative) Worked example .10
Annex B (informative) Extinction curve, example for titanium dioxide.14
Annex C (informative) Effect of radial dilution.15
© ISO 2001 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 13318-2:2002
ISO 13318-2:2001(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 3.
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 part of ISO 13318 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 13318-2 was prepared by Technical Committee ISO/TC 24, Sieves, sieving and other sizing methods,
Subcommittee SC 4, Sizing by methods other than sieving.
ISO 13318 consists of the following parts, under the general title Determination of particle size distribution by
centrifugal liquid sedimentation methods:
Part 1: General principles and guidelines
Part 2: Photocentrifuge method
Part 3: Centrifugal X-ray method
Annexes A to C of this part of ISO 13318 are for information only.
iv © ISO 2001 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 13318-2:2002
ISO 13318-2:2001(E)
Introduction
The sample suspension in a photocentrifuge may be contained in a cuvet or a disc. Sample concentration is
determined by changes in a light signal monitored at a known radius. The cuvet photocentrifuge can only be run in
the homogeneous mode whereas the disc photocentrifuge may be run in either the homogeneous or the line-start
mode. Some systems permit the coarse end of the distribution to be measured in a gravitational mode and the fine
end in the centrifugal mode. The use of light to determine particle size distribution requires a calibration factor to be
applied as the particle size approaches the wavelength of the light, due to the inapplicability of the laws of
geometric optics.
© ISO 2001 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST ISO 13318-2:2002
---------------------- Page: 8 ----------------------
SIST ISO 13318-2:2002
INTERNATIONAL STANDARD ISO 13318-2:2001(E)
Determination of particle size distribution by centrifugal liquid
sedimentation methods —
Part 2:
Photocentrifuge method
WARNING — This part of ISO 13318 may involve hazardous materials, operations and equipment. This part
of ISO 13318 does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user of this part of ISO 13318 to establish appropriate safety and health practices and
determine the applicability of the regulatory limitations prior to its use.
1 Scope
This part of ISO 13318 covers methods for determining the particle size distribution of particulate materials by
means of centrifugal sedimentation in a liquid. Solids concentrations are determined by the transmission of a light
beam. The resulting signal enables conversion to a particle size distribution.
The method of determining the particle size distribution described in this part of ISO 13318 is applicable to powders
that can be dispersed in liquids, powders that are present in slurry form and some emulsions. Typical particle size
range for analysis is from about 0,1 µm to 5 µm. The method is applicable to powders in which all particles have
the same density and comparable shapes and do not undergo chemical or physical change in the suspension
liquid. It is usually necessary that the particles have a density higher than that of the liquid.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 13318. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 13318 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 13318-1, Determination of particle size distribution by centrifugal liquid sedimentation methods — Part 1:
General principles and guidelines
ISO 14887, Sample preparation — Dispersing procedures for powders in liquids
© ISO 2001 – All rights reserved 1
---------------------- Page: 9 ----------------------
SIST ISO 13318-2:2002
ISO 13318-2:2001(E)
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this part of ISO 13318 the terms and definitions of ISO 13318-1 apply.
3.2 Symbols
For the purposes of this this part of ISO 13318 the symbols of ISO 13318-1 and the following apply:
D optical density
E extinction coefficient for a particle of diameter x
i i
G constant dependent upon the geometry of the system, the dimensions of the light beam and on the shape
of the particles
l transmission of the emergent light beam, at the time t, after the start of sedimentation
l transmission of the emergent light beam when no particles are present
0
M distance from rotation axis to measurement zone (mm)
n number of particles of diameter x in the beam
i i
R distance from rotation axis to centrifuge wall, inner disc radius (mm)
S distance from rotation axis to liquid-air interface of sample (mm)
x diameter of the smallest particle in the light beam (µm)
0
x diameter of the largest particle in the light beam i.e. the Stokes diameter (µm)
St
4 Principle
A stable, finely collimated beam of light passes through a spinning disc or cuvet and sedimenting sample and is
detected at a known radius. Light rays, typically from either a white light source (e.g. incandescent bulb) or a
monochromatic coherent source (e.g. laser), pass through the suspension and are detected by a photodiode or
photomultiplier. The disc photocentrifuge can be operated in the line-start or homogeneous mode whereas the
cuvet photocentrifuge can be operated only in the homogeneous mode. The signal of the light beam is monitored
over the analysis time. The mass percentage of sample present in the beam is determined by calculating the ratio
of the light transmission signal, by use of a clear dispersing liquid, to the light transmission signal with the sample
present.
In the line-start mode the disc initially contains clear fill liquid to give maximum light transmission. Then the sample
is injected as a thin layer on top of the spinning fill liquid and begins to settle outward radially. When the largest
particles present reach the light beam the light transmission decreases, returning to the original transmission value
when the smallest particle present passes through the beam. A buffer layer is usually injected over the fill liquid to
prevent suspension breaking through the interface in a phenomenon known as “streaming”.
2 © ISO 2001 – All rights reserved
---------------------- Page: 10 ----------------------
SIST ISO 13318-2:2002
ISO 13318-2:2001(E)
5 Apparatus
5.1 Disc photocentrifuge, with a chamber consisting of a hollow disc with an entry port coaxial with the axis of
rotation (see Figure 1).Typically this is mounted vertically, or at a small angle to the vertical, on to the shaft of an
-1 -1
electric motor with a digitally variable speed typically between 500 r⋅min and 15 000 r⋅min . A white light source
and detector assembly measures transmittance through the suspension as a function of time. The instrument can
be used in either a line-start or homogeneous mode. Extinction coefficient corrections need to be applied for the
breakdown in the laws of geometric optics for both line-start and homogeneous modes. Additionally a correction is
required for radial dilution effects when the homogeneous mode is used. Software is provided with commercial
equipment to convert the data directly into size distributions in the form of tables or graphs of cumulative mass
percentage versus particle size.
5.2 Cuvet photocentrifuge, in which the disc is replaced with a rectangular cell containing a homogeneous
suspension (see Figure 2). Corrections need to be made for both radial dilution and light scattering effects as
described in ISO 13318-1. Cuvet photocentrifuges can typically be run in both the gravitational and centrifugal
modes. Additionally, some systems may offer a gradient mode permitting the centrifuge to accelerate throughout
the analysis in order to reduce the measurement time.
5.3 Ancillary apparatus, consisting of:
dispersing vessel e.g. glass beaker or bottle, of appropriate dimensions;
flexible spatula;
-1
ultrasonic bath or probe, a bottle shaker or high speed mechanical stirrer capable of rotating at 500 r⋅min to
-1
1 000 r⋅min .
Key
1 Motor shaft
2 Spin fluid
3 Buffer layer
4 Suspension
5 Entry port
6 Polymethylmethacrylate disc
Figure 1 — Side view of the disc of a disc photocentrifuge
© ISO 2001 – All rights reserved 3
---------------------- Page: 11 ----------------------
SIST ISO 13318-2:2002
ISO 13318-2:2001(E)
Key
1 Motor
2 Motor control
3 Signal process
4 ADC
5 CPU
6 Date time
7 Analysis parameters
8 RPM
9 Key board
10 Printer
11 Analog interface
12 Computer interface
13 Photo sensor RPM
14 Centrifugal cell
15 Rotating disc
16 LED
17 Photocell (reference)
18 Photocell (sample)
19 Photocells
a
Synchro-signal (reference)
b
Analogue signal
c
Synchro-signal (sample)
Figure 2 — Schematic diagram of a typical cuvet photocentrifuge
4 © ISO 2001 – All rights reserved
---------------------- Page: 12 ----------------------
SIST ISO 13318-2:2002
ISO 13318-2:2001(E)
6 Sampling
For sampling see ISO 13318-1.
7 Preparation
7.1 Sample preparation
An analysis sample shall be prepared as described in ISO 13318-1. The volume and concentration required
depends upon the volume of the centrifuge disc (or cuvet), the sensitivity of the optical-electronic system and
whether the line-start (disc only) or homogeneous method is to be used. In general, lower con
...
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