SIST-TS CEN ISO/TS 19807-2:2023

Nanotechnologies - Magnetic nanomaterials - Part 2: Specification of characteristics and measurement methods for nanostructured magnetic beads for nucleic acid extraction (ISO/TS 19807-2:2021)

This document specifies characteristics to be measured of magnetic beads in suspension and powder forms for nucleic acid extraction applications. This document deals with magnetic beads that contain a substantial amount of magnetic nanoparticles (which can be superparamagnetic). Potential applicable measurement methods are listed for the individual characteristics. Specifically, this document lists critical characteristics of magnetic beads and suspensions, and additional characteristics to describe the magnetic beads and the suspension for nucleic acid extraction.
Health, safety and environmental aspects of magnetic beads are not within the scope of this document.

Nanotechnologien - Magnetische Nanopartikel - Teil 2: Festlegung der Merkmale und Messverfahren für nanostrukturierte magnetische Beads zur Nukleinsäureextraktion (ISO/TS 19807‑2:2021)

Dieses Dokument legt die zu messenden Eigenschaften von magnetischen Beads in Suspensions- und Pulverform für Anwendungen der Nukleinsäure-Extraktion fest. Dieses Dokument behandelt magnetische Beads, die eine erhebliche Menge an magnetischen Nanopartikeln enthalten (die superparamagnetisch sein können). Für die einzelnen Eigenschaften werden mögliche Messverfahren angegeben. Im Einzelnen sind in diesem Dokument wesentliche Eigenschaften von magnetischen Beads und Suspensionen sowie zusätzliche Eigenschaften zur Beschreibung der magnetischen Beads und der Suspension für die Nukleinsäure-Extraktion aufgeführt.
Gesundheits-, Sicherheits- und Umweltaspekte von magnetischen Beads gehören nicht zum Anwendungs¬bereich dieses Dokuments.

Nanotechnologies - Nanomatériaux magnétiques - Partie 2: Spécification des caractéristiques et des méthodes de mesure pour les billes magnétiques nanostructurées pour l’extraction d’acide nucléïque (ISO/TS 19807-2:2021)

Nanotehnologije - Magnetni nanomateriali - 2. del: Specifikacija lastnosti in merilnih metod za nanostrukturirane magnetne kroglice za ekstrakcijo nukleinskih kislin (ISO/TS 19807-2:2021)

Ta dokument določa lastnosti, ki se jih meri pri magnetnih nizih v suspenziji in praških za ekstrakcijo nukleinske kisline. Ta dokument obravnava magnetne nize, ki vsebujejo bistveno količino magnetnih nanodelcev (ki so lahko superparamagnetni nanodelci). Potencialno uporabne merilne metode so navedene za posamezne lastnosti. Ta dokument posebej navaja ključne lastnosti magnetnih nizov in suspenzij in dodatne lastnosti za opis magnetnih nizov in suspenzije za ekstrakcijo nukleinske kisline.
V področje uporabe tega dokumenta niso vključeni vidiki zdravja, varnosti in varstva okolja magnetnih nizov.

General Information

• Status: Published
• Publication Date: 12-Apr-2023
• ICS: 07.120 - Nanotechnologies
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 06-Apr-2023
• Due Date: 11-Jun-2023
• Completion Date: 13-Apr-2023
• Ref Project: CEN ISO/TS 19807-2:2023 - Nanotechnologies - Magnetic nanomaterials - Part 2: Specification of characteristics and measurement methods for nanostructured magnetic beads for nucleic acid extraction (ISO/TS 19807-2:2021)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS CEN ISO/TS 19807-2:2023
01-maj-2023
Nanotehnologije - Magnetni nanomateriali - 2. del: Specifikacija lastnosti in
merilnih metod za nanostrukturirane magnetne kroglice za ekstrakcijo nukleinskih
kislin (ISO/TS 19807-2:2021)
Nanotechnologies - Magnetic nanomaterials - Part 2: Specification of characteristics and
measurement methods for nanostructured magnetic beads for nucleic acid extraction
(ISO/TS 19807-2:2021)
Nanotechnologies - Nanomatériaux magnétiques - Partie 2: Spécification des
caractéristiques et des méthodes de mesure pour les billes magnétiques
nanostructurées pour l’extraction d’acide nucléïque (ISO/TS 19807-2:2021)
Ta slovenski standard je istoveten z: CEN ISO/TS 19807-2:2023
ICS:
07.120 Nanotehnologije Nanotechnologies
SIST-TS CEN ISO/TS 19807-2:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023

---------------------- Page: 2 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023


CEN ISO/TS 19807-2
TECHNICAL SPECIFICATION

SPÉCIFICATION TECHNIQUE

March 2023
TECHNISCHE SPEZIFIKATION
ICS 07.120
English Version

Nanotechnologies - Magnetic nanomaterials - Part 2:
Specification of characteristics and measurement methods
for nanostructured magnetic beads for nucleic acid
extraction (ISO/TS 19807-2:2021)
Nanotechnologies - Nanomatériaux magnétiques -
Partie 2: Spécification des caractéristiques et des
méthodes de mesure pour les billes magnétiques
nanostructurées pour l'extraction d'acide nucléïque
(ISO/TS 19807-2:2021)
This Technical Specification (CEN/TS) was approved by CEN on 17 March 2023 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 19807-2:2023 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
CEN ISO/TS 19807-2:2023 (E)
Contents Page
European foreword . 3

2

---------------------- Page: 4 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
CEN ISO/TS 19807-2:2023 (E)
European foreword
The text of ISO/TS 19807-2:2021 has been prepared by Technical Committee ISO/TC 229
"Nanotechnologies” of the International Organization for Standardization (ISO) and has been taken over
as CEN ISO/TS 19807-2:2023 by Technical Committee CEN/TC 352 “Nanotechnologies” the secretariat
of which is held by AFNOR.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO/TS 19807-2:2021 has been approved by CEN as CEN ISO/TS 19807-2:2023 without any
modification.


3

---------------------- Page: 5 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023

---------------------- Page: 6 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
TECHNICAL ISO/TS
SPECIFICATION 19807-2
First edition
2021-10
Nanotechnologies — Magnetic
nanomaterials —
Part 2:
Specification of characteristics
and measurement methods for
nanostructured magnetic beads for
nucleic acid extraction
Nanotechnologies — Nanomatériaux magnétiques —
Partie 2: Spécification des caractéristiques et des méthodes de mesure
pour les billes magnétiques nanostructurées pour l’extraction d’acide
nucléïque
Reference number
ISO/TS 19807-2:2021(E)
© ISO 2021

---------------------- Page: 7 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
  © ISO 2021 – All rights reserved

---------------------- Page: 8 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviations . 3
5 Characteristics to be measured and measurement methods . 4
5.1 General . 4
5.2 Descriptions of characteristics and their measurement methods . 5
5.2.1 Bead mass concentration . 5
5.2.2 Bead size distribution . 5
5.2.3 Nucleic acid binding capacity . 5
5.2.4 Remanent mass magnetization . 6
5.2.5 Surface functional group type . 7
5.2.6 Saturation mass magnetization . 7
5.2.7 Initial magnetic mass susceptibility . 8
5.2.8 Iron ion concentration . 8
5.2.9 Mass specific surface area . 8
5.2.10 Size of primary magnetic nanoparticles . 9
5.2.11 Surface functional group density . 9
6 Sample preparation .10
7 Test report .10
Annex A (informative) Schematics of magnetic beads .11
Bibliography .12
iii
© ISO 2021 – All rights reserved

---------------------- Page: 9 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(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 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 229, Nanotechnologies.
A list of all parts in the ISO/TS 19807 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.
iv
  © ISO 2021 – All rights reserved

---------------------- Page: 10 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(E)
Introduction
Magnetic beads are composed of a large number of magnetic nanoparticles immobilized within a
nonmagnetic matrix with a size range between tens of nanometres and hundreds of micrometres (see
Annex A). The immobilization matrix is typically based on silica or organic polymers. The beads are
commonly supplied while dispersed in a liquid suspension, for example, ethanol, isopropanol, sodium
azide solutions, pure water. Magnetic beads in liquid suspension have become one of the most widely
used nanomaterials in the biological and chemical fields, due to their unique magnetic properties and
interactions with applied magnetic fields.
When the size of a magnetic object is small enough, it will form a single magnetic domain, behaving as
[1]
a single large macrospin. At yet smaller sizes (for iron oxide, typically less than 30nm ), the thermal
energy of the object can be sufficient to result in frequent reorientations of the magnetization direction
of the object. If the timescale of these reorientations is shorter than the timescale of the measurement,
the term ‘superparamagnetism’ is used to describe this behaviour and the magnetic nano-objects are
said to be superparamagnetic. In large non-interacting ensembles of such particles, the thermally
induced switching events will result in the average magnetization of the ensembles being zero in the
absence of an applied magnetic field. In the presence of an applied large field, the ensemble of magnetic
nano-objects is observed to acquire a large net magnetization, as the magnetic field overcomes the
thermal fluctuations and aligns the macrospins of the individual magnetic nano-objects within the
ensemble. Beads, if incorporating a large fraction of magnetic nano-objects which exhibit this behaviour,
are often referred to as “superparamagnetic beads”. However, as the beads may not themselves be
superparamagnetic, they are referred to as “magnetic beads” herein.
[2]
Magnetic beads have been applied in many fields, especially in biosensing applications such as in vitro
[3]-[5] [6] [7]
diagnostics, targeted drug delivery , magnetic resonance imaging , bioseparation , and genetic
[8]
engineering , among others. For example, nucleic acids, which carry genetic information, can be
extracted or isolated from blood, saliva, faeces, urine, leaves, viral lysates, using suitably functionalized
magnetic beads.
The nucleic acids (DNA) and ribonucleic acid (RNA) carry the key information that organisms use to
build or maintain their biostructures. Correctly identifying DNA offers immensely valuable information
on health. In recent years, in the human blood stream, scientists have not only found circulating cell
free DNA (cfDNA), but also circulating tumour DNA (ctDNA). Now ctDNA extraction is one of the most
widely used liquid-biopsy methods to determine cancer or track cancer development. However, the
content of ctDNA is only 1 % or less of the total cfDNA amount. The concentration of cfDNA is very
low, generally 5 ng/ml blood to 30 ng/ml blood. Therefore, the development of reliable methods for
extracting the ctDNA is critical. The proper description of physicochemical characteristics of magnetic
beads for DNA extraction is both valuable for developers of extraction kits and for users applying them
for DNA analysis.
Nucleic acid binding to magnetic beads relies on electrostatic interactions, hydrophobic interactions,
hydrogen bonding or specific binding mechanisms to the bead surface. Once DNA or RNA from cell or
tissue lysate is released into the solution, then nucleic acids can bind to surface-modified magnetic
[9]-[19]
beads to form a “nucleic acid-magnetic bead complex”.
Then, the complex can be separated under a proper combination of magnetic field and magnetic field
gradient. The eluate can wash away the residual impurities. Finally, the nucleic acids to be extracted
[9]-[19]
can be obtained from the beads after desalination and purification.
The different forms of magnetic beads and dispersing media for the extraction of nucleic acid will have
different physicochemical characteristics such as specific surface area, bead concentration etc. All
[9]-[19]
these characteristics will affect their performance to extract nucleic acid to varying extents.
In common with other nanostructured materials, the manufacturing and material specification of
composite magnetic beads are complex. Small variations in the synthesis conditions during bead
manufacturing and functionalization can lead into dramatic shifts in the properties and binding
capacities of the manufactured beads. This requires these products to have high manufacturing
consistency. Currently, different manufacturers provide different characteristics and most of them
v
© ISO 2021 – All rights reserved

---------------------- Page: 11 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(E)
never provide the measurement methods, so it is difficult for consumers or regulators to compare
different products or to verify the characteristics, which increases the difficulty of further development
of the application. Universally accepted material specification and test reports for magnetic beads are
a requirement in order to ensure customer confidence and the quality of the nucleic acid extraction
products.
vi
  © ISO 2021 – All rights reserved

---------------------- Page: 12 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
TECHNICAL SPECIFICATION ISO/TS 19807-2:2021(E)
Nanotechnologies — Magnetic nanomaterials —
Part 2:
Specification of characteristics and measurement methods
for nanostructured magnetic beads for nucleic acid
extraction
1 Scope
This document specifies characteristics to be measured of magnetic beads in suspension and powder
forms for nucleic acid extraction applications. This document deals with magnetic beads that contain a
substantial amount of magnetic nanoparticles (which can be superparamagnetic). Potential applicable
measurement methods are listed for the individual characteristics. Specifically, this document lists
critical characteristics of magnetic beads and suspensions, and additional characteristics to describe
the magnetic beads and the suspension for nucleic acid extraction.
Health, safety and environmental aspects of magnetic beads are not within the scope of this document.
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/TS 80004-1, Nanotechnologies — Vocabulary — Part 1: Core terms
ISO/TS 80004-6, Nanotechnologies — Vocabulary — Part 6: Nano-object characterization
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/TS 80004-1, ISO/TS 80004-6
and the following 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
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
bead mass concentration
ratio of the mass of magnetic beads (3.6) to the total volume of a magnetic beads sample in suspension
or powder form
3.2
bead size
effective outer diameter of a magnetic bead (3.6) determined by using the specified measurement
method
1
© ISO 2021 – All rights reserved

---------------------- Page: 13 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(E)
3.3
bead size distribution
distribution of beads as a function of bead size (3.2)
Note 1 to entry: Bead size distribution may be expressed as cumulative distribution or a distribution density
(distribution of the fraction of beads in a size class, divided by the width of that class).
3.4
dispersing medium
liquid in which magnetic beads (3.6) are suspended
3.5
initial magnetic mass susceptibility
differential ratio of the change in mass magnetization of a material to the amplitude of a magnetic field
change at a sufficiently small absolute magnetic field
Note 1 to entry: A magnetic beads (3.6) sample is assumed to be magnetically isotropic and its initial magnetic
mass susceptibility is indicated as a scalar.
3.6
magnetic bead
small round piece containing a large number of magnetic nanoparticles which can be superparamagnetic
and are immobilized within a non-magnetic matrix
Note 1 to entry: The size range of magnetic beads for DNA extraction spans from a few tens of nanometres to
several micrometres.
3.7
mass-specific surface area
absolute surface area of the sample divided by sample mass
[SOURCE: ISO/TS 80004-6:2021, 4.6.1, modified — Note 1 to entry has been removed.]
3.8
nucleic acid
macromolecule that is the medium for genetic information or acts as an agent in expressing the
information
Note 1 to entry: There are two types of nucleic acid, DNA and RNA.
[SOURCE: ISO 17822:2020, 3.32]
3.9
nucleic acid binding capacity
mass of nucleic acid (3.8) bound to the surfaces of magnetic beads (3.6) per unit mass of the magnetic
beads under specified conditions
3.10
operational time
maximum time after the start of the extraction process where the suspension of magnetic beads (3.6) is
ready for use to extract nucleic acid (3.8)
Note 1 to entry: the operational time is usually recommended by the manufacturer.
3.11
remanent mass magnetization
value of the mass magnetization remaining in a magnetized body when, in the absence of a self-
demagnetizing field, the applied magnetic field strength is brought to zero
[SOURCE: IEC 60050:1990, 221-02-40, modified — "magnetization" has been changed to "mass
magnetization".]
2
  © ISO 2021 – All rights reserved

---------------------- Page: 14 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(E)
3.12
saturation mass magnetization
limiting value of the mass magnetization of a liquid or dried sample with increasing applied magnetic
field strength
Note 1 to entry: The saturation mass magnetization of magnetic beads (3.6) is indicated for the dried matter of a
bead suspension sample or for the dried sample in the case of beads in powder form.
3.13
shelf life
recommended time period by manufacturer during which a product (suspension or powder) can be
stored, throughout which the defined quality of specified characteristics of the product remains
acceptable under expected (or specified) conditions of distribution, storage, display and usage
Note 1 to entry: Defined characteristics should be measured after fixed time intervals.
[SOURCE: ISO/TS 19807-1:2019, 3.37, modified — the manufacturer has been specified and the powder
product has been added.]
3.14
surface functional group density
mass of surface functional groups per unit mass of magnetic beads (3.6)
3.15
surface functional group type
chemical type of substituents or moieties on the surface of magnetic beads (3.6) that are responsible for
a specific chemical reaction
4 Abbreviations
For the purposes of this document, the following abbreviations apply:
BET method Brunauer–Emmett–Teller method
DLS Dynamic light scattering
DNA Deoxyribonucleic acid
ICP-OES Inductively coupled plasma optical emission spectrometry
IR Infrared
PCR Polymerase chain reaction
RNA Ribonucleic acid
SEM Scanning electron microscopy
SQUID Superconducting quantum interference device
TEM Transmission electron microscopy
UV-Vis spec- Ultraviolet-visible spectrometry
trometry
VSM Vibrating sample magnetometry
XPS X-ray photoelectron spectroscopy
3
© ISO 2021 – All rights reserved

---------------------- Page: 15 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(E)
5 Characteristics to be measured and measurement methods
5.1 General
The critical characteristics listed in Table 1 of magnetic beads products supplied for nucleic acid
extraction shall be measured. The additional characteristics listed in Table 2 are frequently measured
in industrial communities depending on the application. However, whether to provide these additional
characteristics is optional for the supplier. The selection criteria for the first table are the critical
characteristics of magnetic beads and suspensions. They determine fundamentally the extraction
performance, independent of the nucleic acid sample type or the subsequent extraction process.
The additional characteristics can influence the extraction performance, depending on the specific
application or process.
Measurement methods and relevant standards for these methods are listed in Tables 1 and 2. Listed
measurement methods can be alternatively used. However, other measurement methods may also be
used as agreed between supplier and purchaser. Any characteristic from these tables shall be reported
by stating its value and the measurement method used. The listed ISO documents for measurements
have been generally applied to measurements for characteristics of non-magnetic objects. However,
it should be noted that these ISO documents have not yet been fully validated for the application to
magnetic beads.
Tables 1 and 2 provide alternative measurement methods for some characteristics. It should be noted
that the values of characteristics obtained by a measurement method can deviate to some extent from
that obtained by another measurement method.
Table 1 — Critical characteristics of magnetic beads to be measured
Characteristics Measurement method Relevant standards
[20]
Bead mass concentration Gravimetry and oven drying ISO 11358-1
[21]-[24] [25]
DLS ISO 22412
[21],[23] [26]
SEM ISO 19749
[21]-[23] [27]
TEM ISO 21363
Bead size distribution
[29]
ISO 20998-1
[28]
Ultrasonic attenuation spectroscopy
[30]
ISO 20998-3
[31] [32]
Electrical sensing zone ISO 13319-1
[33],[34] [35]
UV-Vis spectrometry ISO 21571
Nucleic acid binding
[36],[37] [35]
Real-time PCR ISO 21571
capacity
[38] [35]
Agarose gel electrophoresis ISO 21571
[39],[40]
SQUID magnetometry
Remanent mass magneti-
zation [21],[22],[41]
VSM
[21],[24],[42]
IR
Surface functional group
[43]
type
XPS ISO 20903
SQUID magnetometry
Saturation mass magnet-
ization
VSM
Table 2 — Additional characteristics of magnetic beads to be measured
Characteristics Measurement method Relevant standards
VSM
Initial magnetic mass
susceptibility
SQUID magnetometry
[44] [45]
Iron ion concentration ICP-OES ISO 11885
4
  © ISO 2021 – All rights reserved

---------------------- Page: 16 ----------------------
SIST-TS CEN ISO/TS 19807-2:2023
ISO/TS 19807-2:2021(E)
Table 2 (continued)
Characteristics Measurement method Relevant standards
[48]
ISO 9277
[46],[47]
Mass specific surface area Gas adsorption method
[49]
ISO 18757
Size of primary magnetic
[27]
TEM ISO 21363
nanoparticles
Surface functional group
Conductometric titration
density
5.2 Descriptions of characteristics and their measurement methods
5.2.1 Bead mass concentration
The bead mass concentration of a sample of magnetic beads in suspension or in powder form is the
ratio of the mass of the magnetic beads to the total volume of the sample.
The mass of the beads after drying shall be measured by the oven drying method. For oven drying of
magnetic beads in suspension, a certain volume of the suspension shall be washed by deionized water
and separated by magnetic separation several times to remove any soluble ingredients in the dispersing
medium. This makes sure that the soluble content in the dispersing medium in the bead suspension is
neglectable.
Then, the sample in powder or suspension form shall be dried until a constant mass is reached which
is determined by weighing. The temperature used for drying shall induce the evaporation of the liquid
compartments of the sample but not lead to decomposition of the beads. For water-based suspensions,
the drying temperature is typically 105 °C ± 2 °C.
The bead mass concentration is expressed in the unit kg/l.
NOTE 1 The bead mass concentration is correctly measured when solid materials other than the magnetic
beads are negligible in the sample. Otherwise, the measurement result includes the mass of the other solid
materials.
NOTE 2 If the mass of the dried beads is divided by the total sample mass measured before drying, the result
is called dry matter content and it is expressed in the unit kg/kg.
5.2.2 Bead size distribution
The bead siz
...