SIST EN 17265:2019

Foodstuffs - Determination of elements and their chemical species - Determination of aluminium by inductively coupled plasma optical emission spectometry (ICP-OES)

This document describes a method for the determination of aluminium in food by inductively coupled plasma optical emission spectrometry (ICP-OES) after pressure digestion. This method is suitable for mass fraction in the range of 15 mg/kg to 200 mg/kg. At concentrations above 200 mg/kg digestion temperatures higher than 220 °C can be necessary to recover the aluminium as completely as possible.

Lebensmittel - Bestimmung von Elementen und ihren Verbindungen - Bestimmung von Aluminium mit der optischen Emissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP-OES)

Dieses Dokument legt ein Verfahren zur Bestimmung von Aluminium in Lebensmitteln mittels optischer Emissionsspektrometrie mit induktiv gekoppeltem Plasma (ICP-OES) nach Druckaufschluss fest. Dieses Verfahren wurde für Weizennudeln, Käse, Leber, rote Bete und Kakaopulver mit Massenanteilen im Bereich von 15 mg/kg bis 200 mg/kg validiert. Bei Konzentrationen über 200 mg/kg können höhere Aufschluss-temperaturen als 220 °C notwendig sein, um das Aluminium möglichst vollständig zu erfassen.

Produits alimentaires - Dosage des éléments et de leurs espèces chimiques - Dosage de l'aluminium par spectrométrie d'émission optique avec plasma à couplage inductif (ICP-OES)

Le présent document décrit une méthode de dosage de l’aluminium dans les aliments par spectrométrie d’émission optique avec plasma à couplage inductif (ICP-OES) après digestion sous pression. Cette méthode a été validée pour les nouilles de blé, le fromage, le foie, la betterave et la poudre de cacao, pour des fractions massiques allant de 15 mg/kg à 200 mg/kg. À des fractions massiques supérieures à 200 mg/kg, des températures de digestion dépassant 220 °C peuvent être nécessaires pour obtenir un taux de récupération maximal de l’aluminium.

Živila - Določevanje elementov in njihovih spojin - Določevanje aluminija z optično emisijsko spektrometrijo z induktivno sklopljeno plazmo (ICP-OES)

Ta dokument opisuje metodo za določevanje aluminija v hrani z optično emisijsko spektrometrijo z induktivno sklopljeno plazmo (ICP-OES) po razklopu pod tlakom. Ta metoda je primerna za masni delež v območju od 15 mg/kg do 200 mg/kg. Pri koncentracijah nad 200 mg/kg bodo morda potrebne temperature razklopa nad 220 °C, da se aluminij pridobi v čim bolj popolni obliki.

General Information

• Status: Published
• Public Enquiry End Date: 09-Oct-2018
• Publication Date: 14-Oct-2019
• ICS: 67.050 - General methods of tests and analysis for food products
• Technical Committee: KŽP - Agricultural food products
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 24-Sep-2019
• Due Date: 29-Nov-2019
• Completion Date: 15-Oct-2019
• Directive: 882/2004 - Regulation (EC) No 882/2004 of the European Parliament and of the Council of 29 April 2004 onofficial controls performed to ensure the verification of compliance with feed and food law, animal health and animal welfare rules
• Ref Project: EN 17265:2019 - Foodstuffs - Determination of elements and their chemical species - Determination of aluminium by inductively coupled plasma optical emission spectometry (ICP-OES)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 17265:2019
01-november-2019
Živila - Določevanje elementov in njihovih spojin - Določevanje aluminija z optično
emisijsko spektrometrijo z induktivno sklopljeno plazmo (ICP-OES)
Foodstuffs - Determination of elements and their chemical species - Determination of
aluminium by inductively coupled plasma optical emission spectometry (ICP-OES)
Lebensmittel - Bestimmung von Elementen und ihren Verbindungen - Bestimmung von
Aluminium mit der optischen Emissionsspektrometrie mit induktiv gekoppeltem Plasma
(ICP-OES)
Produits alimentaires - Dosage des éléments et de leurs espèces chimiques - Dosage de
l'aluminium par spectrométrie d'émission optique avec plasma à couplage inductif (ICP-
OES)
Ta slovenski standard je istoveten z: EN 17265:2019
ICS:
67.050 Splošne preskusne in General methods of tests and
analizne metode za živilske analysis for food products
proizvode
SIST EN 17265:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 17265:2019

---------------------- Page: 2 ----------------------
SIST EN 17265:2019


EN 17265
EUROPEAN STANDARD

NORME EUROPÉENNE

September 2019
EUROPÄISCHE NORM
ICS 67.050
English Version

Foodstuffs - Determination of elements and their chemical
species - Determination of aluminium by inductively
coupled plasma optical emission spectometry (ICP-OES)
Produits alimentaires - Dosage des éléments et de leurs Lebensmittel - Bestimmung von Elementen und ihren
espèces chimiques - Dosage de l'aluminium par Verbindungen - Bestimmung von Aluminium mittels
spectrométrie d'émission optique avec plasma à optischer Emissionsspektrometrie mit induktiv
couplage inductif (ICP-OES) gekoppeltem Plasma (ICP-OES)
This European Standard was approved by CEN on 28 July 2019.

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-CENELEC 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-CENELEC Management
Centre has the same status as the official versions.

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, Turkey 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17265:2019 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
SIST EN 17265:2019
EN 17265:2019 (E)
Contents Page
European foreword . 3
1 Scope . 3
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 4
6 Apparatus . 6
7 Procedure. 6
7.1 Digestion . 6
7.2 Inductively coupled plasma optical emission spectrometry . 8
8 Evaluation . 9
8.1 Calculation . 9
8.2 Precision . 9
8.3 Repeatability . 9
8.4 Reproducibility . 10
9 Test report . 10
Annex A (informative) Results of interlaboratory study . 11
Annex B (normative) Explanation notes . 13
Annex C (normative) Spectral interferences . 15
Bibliography . 16

2

---------------------- Page: 4 ----------------------
SIST EN 17265:2019
EN 17265:2019 (E)
European foreword
This document (EN 17265:2019) has been prepared by Technical Committee CEN/TC 275 “Food
analysis - Horizontal methods”, 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 March 2020, and conflicting national standards shall
be withdrawn at the latest by March 2020.
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.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Turkey and the
United Kingdom.
3

---------------------- Page: 5 ----------------------
SIST EN 17265:2019
EN 17265:2019 (E)
1 Scope
This document specifies a method for the determination of aluminium in food by inductively coupled
plasma optical emission spectrometry (ICP-OES) after pressure digestion. This method was validated
for wheat noodle, cheese, liver, beetroot and cocoa powder at mass fractions in the range of 15 mg/kg
to 200 mg/kg. At concentrations above 200 mg/kg digestion temperatures higher than 220 °C can be
necessary to recover the aluminium as completely as possible.
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.
EN 13804, Foodstuffs - Determination of elements and their chemical species - General considerations and
specific requirements
EN 13805, Foodstuffs - Determination of trace elements - Pressure digestion
EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696)
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
4 Principle
Aluminium is determined quantitatively by ICP-OES after digestion of the sample with nitric acid (with
addition of water in case of foods with low water content), according to the pressure digestion process
described in EN 13805 but without the use of hydrofluoric acid. The digestion conditions are chosen in
such a way that even for samples with aluminium compounds of low solubility (e.g. silicates, oxides)
low findings are kept to a minimum.
5 Reagents
The mass concentration of aluminium shall be low enough in the reagents and water not to affect the
results.
All reagents shall be of analytical grade, i.e. pro analysi, p.a. or similar unless otherwise specified.
Use water conforming to grade 2 of EN ISO 3696.
5.1 Nitric acid, mass fraction w = at least 65 %, density = 1,4 g/ml.
5.2 Aluminium stock solution, mass concentration ρ = 1 000 mg/l.
4

---------------------- Page: 6 ----------------------
SIST EN 17265:2019
EN 17265:2019 (E)
5.3 Scandium stock solution, ρ = 1 000 mg/l as internal standard.
Scandium is mentioned as an example of an internal standard. Yttrium and Ytterbium are suitable as
well. Only a negligible quantity of the internal standard may be present in the sample. Wavelengths of
Scandium, Yttrium and Ytterbium can be found in the manufacturer requirements of the ICP-OES.
5.4 Standard solutions
5.4.1 General
When preparing solutions, special care shall be taken to avoid contaminations. For aluminium there are
various sources of contamination, e.g. volumetric flasks made of glass. Annex B of this document
requires special attention.
5.4.2 Aluminium standard solution, ρ = 10 mg/l.
Fill 10 ml of water into a 50-ml volumetric flask, add 2 ml of nitric acid (5.1) and mix. After cooling
down to room temperature, pipette exactly 500 µl of the aluminium stock solution (5.2) to the flask and
fill up with water to the mark. This standard solution is stable for at least 3 months.
5.4.3 Scandium standard solution (internal standard solution), ρ = 10 mg/l.
Fill approximately 10 ml of water into a 50-ml volumetric flask, add 2 ml of nitric acid (5.1) and mix.
After cooling down to room temperature, pipette exactly 500 µl of the scandium stock solution (5.3) to
the flask and fill up with water to the mark. This standard solution is stable for at least 3 months.
5.5 Aluminium calibration solutions.
The concentrations of the calibration solutions described are examples and may be changed according
to the sensitivity of the measuring instrument and the concentration range to be analysed. Carry out the
calibration within the linear range of the detector system. At least 3 calibration solutions of different
concentrations should be prepared. Make sure that the acid concentration of the calibration solutions
corresponds to the test solution.
In order to avoid contaminations originating from the flask material, do not use volumetric flasks made
from borosilicate glass. The information on contaminations provided in B.1 is to be regarded.
Mix all calibration and test solutions as well as the zero-point solution (5.6) with an equal proportion of
internal standard solution (5.4.3).
The calibration solutions are prepared from the standard solution (5.4.2) according to the following
scheme in Table 1:
Table 1 — Example of aluminium calibration solutions
Calibration solution no Volume of standard Volume of internal Mass concentration
solution (5.4.2) standard solution of aluminium in the
(5.4.3) calibration solution
µl µl mg/l
1 100 2 000 0,05
2 200 2 000 0,10
3 500 2 000 0,25
4 1 000 2 000 0,50
5 2 000 2 000 1,00
5

---------------------- Page: 7 ----------------------
SIST EN 17265:2019
EN 17265:2019 (E)
EXAMPLE Fill 4 ml to 5 ml of water into a 20-ml volumetric flask, add 1,25 ml of nitric acid (5.1) and mix.
After cooling down to room temperature, pipette standard solution and internal standard solution according to
Table 1 above to the flask, fill up to the mark with water, and mix.
Alternatively the internal standard solution can be pumped into the sample flow via a Y-piece during
measurement. In this case the internal standard solution is not pipetted into the calibration solutions.
NOTE The acid concentration of the calibration solution in the example is adapted to a digestion with 2,5 ml
of nitric acid (5.1), a filling volume of 20 ml, and a dilution factor of 2 (in case of a dilution with water).
The calibration solutions shall be freshly prepared each working day.
5.6 Zero-point solution
20 ml of zero-point solution contain water, 1,25 ml of nitric acid (5.1) and 2 000 µl internal standard
solution (5.4.3) according to the example given in 5.5.
6 Apparatus
All equipment and labware that come into direct contact with the sample and the solutions used shall
be carefully pretreated/cleaned according to EN 13804 to minimize the blank value (see Annex B for
details). In addition to standard laboratory equipment, use the following:
6.1 Inductively coupled plasma optical emission spectrometer (ICP-OES).
Optical emission spectrometer with inductively coupled argon plasma, sample supply and atomization
system as well as device control and data acquisition. The instrument settings shall allow the
measurement of the emission intensities on both sides of the emission line and enable a spectral
background correction on both sides [1] [2].
6.2 Digestion vessels, e.g. of polyfluoropolymers or quartz with volumes from 70 ml to 100 ml.
6.3 Test tube shaker, optional.
6.4 Analytical balance, capable to weigh to the nearest milligram.
7 Procedure
7.1 Digestion
7.1.1 General
To ensure complete dissolution of aluminium the following shall be respected:
— ensure that the sample is sufficiently homogeneous;
— in case of incomplete digestion or high aluminium contents, it may be beneficial to use a test
portion as small as possible (at least 200 mg for dry samples) in order to digest aluminium
compounds as completely as possible;
— for samples containing silicates, digestion temperatures above 220 °C may be necessary in order to
dissolve the aluminium as completely as possible;
— in case of samples with low water content, first add water and mix intensively, before adding
concentrated nitric acid;
— do not use hydrogen peroxide for digestion.
6

---------------------- Page: 8 ----------------------
SIST EN 17265:2019
EN 17265:2019 (E)
Further instructions regarding test portions and digestion are given in B.2 and B.3.
For pressure digestion according to EN 13805, different vessels may be used depending on the
instrument type and manufacturer. The maximum test portion and the minimum liquid volume depend
on the pressure stability of the respective vessels. The specifications according to 7.1.2 refer to
digestion vessels with volumes from 70 ml to 100 ml and a minimum liquid volume of 5 ml.
All indications in 7.1.2 shall be adjusted to the digestion instrument used. For safety reasons the
manufacturer's specifications shall be strictly followed.
7.1.2 Digestion procedure
Before digestion, different amounts of water, depending on the different types of food [3], are added in
order to obtain comparable acid concentrations in the final digestion solution. The amount of water to
be added depends on the test portion and thus on the content of carbon and water in the food type.
Add just as much water to the test portion that is necessary to suspend the food completely. Then
complete the test portion with water to reach 3 g. Water is also added to fat-containing foods, even if a
suspension is hardly possible.
Example for digestion of powdery food: Add 2,5 ml of water to the dry food, e.g. 0,5 g of flour. Mix the
contents of the digestion vessel intensively, e.g. on a test-tube shaker. Repeat shaking every 10 min to
15 min until the suspension is homogeneous. No agglutinated particles shall remain, and the sample
material shall be welled. Fat-containing samples require more time and repeated shaking. After at least
30 min, add 2,5 ml of nitric acid (5.1) to the sample. Mix thoroughly again to obtain a homogeneous
suspension. After the pre-reaction has subsided, close the digestion vessel, and start the digestion.
Example for digestion of a sample with high water content, e.g. lettuce: Directly add 2,5 ml of nitric acid
(5.1) to 3 g of lettuce and mix thoroughly. It is not necessary to add water. After the pre-reaction has
subsided, close the digestion vessel, and start the digestion.
A digestion temperature of at least 200 °C to be kept for at least 20 min is required for a complete
digestion in the microwave.
...

SLOVENSKI STANDARD
oSIST prEN 17265:2018
01-oktober-2018
äLYLOD'RORþHYDQMHHOHPHQWRYLQQMLKRYLKNHPLMVNLKREOLN'RORþHYDQMHDOXPLQLMD
]RSWLþQRHPLVLMVNRVSHNWURPHWULMR]LQGXNWLYQRVNORSOMHQRSOD]PR,&32(6
Foodstuffs - Determination of elements and their chemical species - Determination of
aluminium by inductively coupled plasma optical emission spectometry (ICP-OES)
Lebensmittel - Bestimmung von Elementen und ihren Verbindungen - Bestimmung von
Aluminium mit der optischen Emissionsspektrometrie mit induktiv gekoppeltem Plasma
(ICP-OES)
Produits alimentaires - Dosage des éléments et de leurs espèces chimiques - Dosage de
l'aluminium par spectrométrie d'émission optique avec plasma à couplage inductif (ICP-
OES)
Ta slovenski standard je istoveten z: prEN 17265
ICS:
67.050 Splošne preskusne in General methods of tests and
analizne metode za živilske analysis for food products
proizvode
oSIST prEN 17265:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN 17265:2018

---------------------- Page: 2 ----------------------
oSIST prEN 17265:2018


DRAFT
EUROPEAN STANDARD
prEN 17265
NORME EUROPÉENNE

EUROPÄISCHE NORM

July 2018
ICS 67.050
English Version

Foodstuffs - Determination of elements and their chemical
species - Determination of aluminium by inductively
coupled plasma optical emission spectometry (ICP-OES)
Produits alimentaires - Dosage des éléments et de leurs Lebensmittel - Bestimmung von Elementen und ihren
espèces chimiques - Dosage de l'aluminium par Verbindungen - Bestimmung von Aluminium mit der
spectrométrie d'émission optique avec plasma à optischen Emissionsspektrometrie mit induktiv
couplage inductif (ICP-OES) gekoppeltem Plasma (ICP-OES)
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 275.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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-CENELEC
Management Centre has the same status as the official versions.

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

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.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17265:2018 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
oSIST prEN 17265:2018
prEN 17265:2018 (E)
Contents
Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents . 4
6 Apparatus . 6
7 Procedure . 6
7.1 Digestion . 6
7.1.1 General . 6
7.1.2 Digestion procedure . 7
7.2 Inductively coupled plasma optical emission spectrometry . 7
7.2.1 ICP-OES operating conditions . 7
7.2.2 Determination by ICP-OES . 8
7.2.3 Quality control . 8
8 Evaluation . 8
8.1 Calculation . 8
8.2 Precision . 9
8.3 Repeatability . 9
8.4 Reproducibility . 9
9 Test report . 9
Annex A (informative) Results of interlaboratory study . 10
Annex B (informative) Explanation notes . 13
B.1 Information on contaminations . 13
B.2 Information on test portions . 13
B.3 Information on digestion . 13
B.4 Reference materials . 14
Annex C (informative) Further information . 15
Bibliography . 16

2

---------------------- Page: 4 ----------------------
oSIST prEN 17265:2018
prEN 17265:2018 (E)
European foreword
This document (prEN 17265:2018) has been prepared by Technical Committee CEN/TC 275 “Food
Analysis – Horizontal methods”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
3

---------------------- Page: 5 ----------------------
oSIST prEN 17265:2018
prEN 17265:2018 (E)
1 Scope
This document describes a method for the determination of aluminium in food by inductively coupled
plasma optical emission spectrometry (ICP-OES) after pressure digestion. This method is suitable for
mass fraction in the range of 15 mg/kg to 200 mg/kg. At concentrations above 200 mg/kg digestion
temperatures higher than 220 °C can be necessary to recover the aluminium as completely as possible.
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.
EN 13804, Foodstuffs - Determination of elements and their chemical species - General considerations and
specific requirements
EN 13805, Foodstuffs - Determination of trace elements - Pressure digestion
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Principle
Aluminium is determined quantitatively by ICP-OES after digestion of the sample with nitric acid, with
addition of water in case of foods with low water content, according to the pressure digestion process
described in EN 13805 but without the use of hydrofluoric acid. The digestion conditions are chosen in
such a way that even for samples with aluminium compounds of low solubility (e.g. silicates, oxides)
low findings are kept to a minimum.
5 Reagents
The mass concentration of aluminium shall be low enough in the reagents and water not to affect the
results.
All reagents shall be of analytical grade, i.e. pro analysi, p.a. or similar unless otherwise specified.
Use water conforming to grade 2 of EN ISO 3696.
5.1 Nitric acid, mass fraction w = at least 65 %, density = 1,4 g/ml
5.2 Aluminium stock solution, mass concentration ρ = 1000 mg/l
5.3 Scandium stock solution, ρ = 1000 mg/l as internal standard
Scandium is mentioned as an example of an internal standard. Scandium, yttrium and ytterbium are
suitable as well. Only a negligible quantity of the internal standard may be present in the sample.
4

---------------------- Page: 6 ----------------------
oSIST prEN 17265:2018
prEN 17265:2018 (E)
5.4 Standard solutions
5.4.1 General
When preparing solutions special care shall be taken to avoid contaminations. For aluminium there are
various sources of contamination, e.g. volumetric flasks made of glass. Annex B of this document
requires special attention.
5.4.2 Aluminium standard solution, ρ = 10 mg/l
Fill 10 ml of water into a 50-ml volumetric flask, add 2 ml of nitric acid (5.1) and mix. After cooling
down to room temperature, pipette exactly 500 µl of the aluminium stock solution (5.2) to the flask and
fill up with water to the mark. This standard solution is stable for at least 3 months.
5.4.3 Rhodium standard solution (internal standard solution), ρ = 10 mg/l
Fill approximately 10 ml of water into a 50-ml volumetric flask, add 2 ml of nitric acid (5.1) and mix.
After cooling down to room temperature, pipette exactly 500 µl of the scandium stock solution (5.3)to
the flask and fill up with water to the mark. This standard solution is stable for at least 3 months.
5.5 Aluminium calibration solutions
The concentrations of the calibration solutions described are examples and may be changed according
to the sensitivity of the measuring instrument and the concentration range to be analysed. Carry out the
calibration within the linear range of the detector system. At least 3 calibration solutions of different
concentrations should be prepared. Make sure that the acid concentration of the calibration solutions
corresponds to the test solution.
In order to avoid contaminations originating from the flask material, do not use volumetric flasks made
from borosilicate glass. The information on contaminations provided in B.1 is to be regarded.
Mix all calibration and test solutions as well as the zero-point solution with an equal proportion of
internal standard solution (5.4.3).
The calibration solutions are prepared from the standard solution (5.4.2) according to the following
scheme in Table 1:
Table 1 — Example of aluminium calibration solutions
Calibration solution no Volume of standard Volume of internal Mass concentration
solution (5.4.2) standard solution of aluminium in the
(5.4.3) calibration solution
µl µl mg/l
1 100 2000 0,05
2 200 2000 0,10
3 500 2000 0,25
4 1000 2000 0,50
5 2000 2000 1,00
EXAMPLE Fill 4 ml to 5 ml of water into a 20-ml volumetric flask, add 1,25 ml of nitric acid (5.1) and mix.
After cooling down to room temperature, pipette standard solution and internal standard solution according to
Table 1 above to the flask, fill up to the mark with water, and mix.
5

---------------------- Page: 7 ----------------------
oSIST prEN 17265:2018
prEN 17265:2018 (E)
Alternatively the internal standard solution can be pumped into the sample flow via a Y-piece during
measurement. In this case the internal standard solution is not pipetted into the calibration solutions.
NOTE The acid concentration of the calibration solution in the example is adapted to a digestion with 2,5 ml of
nitric acid (5.1), a filling volume of 20 ml, and a dilution factor of 2 (in case of a dilution with water).
The calibration solutions shall be freshly prepared each working day.
5.6 Zero-point solution
20 ml of zero-point solution contain water, 1,25 ml of nitric acid (5.1) and 2 000 µl internal standard
solution (5.4.3) according to the example given in 5.5.
6 Apparatus
All equipment and labware that come into direct contact with the sample and the solutions used shall
be carefully pretreated/cleaned according to EN 13804 to minimize the blank value (see Annex B for
details). In addition to standard laboratory equipment, use the following:
6.1 Inductively coupled plasma optical emission spectrometer (ICP-OES)
Optical emission spectrometer with inductively coupled argon plasma, sample supply and atomization
system as well as device control and data acquisition. The instrument settings shall allow the
measurement of the emission intensities on both sides of the emission line and enable a background
correction on both sides.
6.2 Digestion vessels, e.g. of tetrafluoroethylene or quarz with volumes from 70 ml to 100 ml
6.3 Test tube shaker, optional
7 Procedure
7.1 Digestion
7.1.1 General
To quantify aluminium in food certain basic conditions shall be respected especially during digestion:
— in case of high aluminium contents it could be beneficial to use a test portion as small as possible
(at least 200 mg for dry samples) in order to digest aluminium compounds as completely as
possible. Ensure that the sample is sufficiently homogeneous;
— in case of samples with low water content, first add water and mix intensively, before adding
concentrated nitric acid. Do not use hydrogen peroxide;
— for samples containing silicates digestion temperatures above 200 °C can be necessary in order to
quantify the aluminium as completely as possible.
Further instructions regarding test portions and digestion are given in B.2 and B.3.
For pressure digestion according to EN 13805, different vessels may be used depending on the
instrument type and manufacturer. The maximum test portion and the minimum liquid volume depend
on the pressure stability of the respective vessels. The specifications according to 7.2 refer to digestion
vessels with volumes from 70 ml to 100 ml and a minimum liquid volume of 5 ml.
All indications in 7.2 shall be adjusted to the digestion instrument used. For safety reasons the
manufacturer's specifications shall be strictly followed.
6

---------------------- Page: 8 ----------------------
oSIST prEN 17265:2018
prEN 17265:2018 (E)
7.1.2 Digestion procedure
Before digestion different amounts of water, depending on the different types of food [7], are added in
order to obtain comparable acid concentrations in the final digestion solution. The amount of water to
be added depends on the test portion and thus on the content of carbon and water in the food type.
Add just as much water to the test portion that is necessary to suspend the food completely. Then
complete the test portion with water to reach 3 g. Water is also added to fat-containing foods, even if a
suspension is hardly possible.
EXAMPLE 1 Example for digestion of powdery food: Add 2,5 ml of water to the dry food, e.g. 0,5 g of flour. Mix
the contents of the digestion vessel intensively, e.g. on a test-tube shaker. Repeat shaking every 10 min to 15 min
until the suspension is homogeneous. No agglutinated particles shall remain, and the sample material shall be
welled. Fat-containing samples require more time and repeated shaking. After at least 30 min, add 2,5 ml of nitric
acid (5.1) to the sample. M
...