SIST EN ISO 23821:2023
(Main)Cosmetics - Analytical methods - Determination of traces of mercury in cosmetics by atomic absorbtion spectrometry (AAS) cold vapour technology after pressure digestion (ISO 23821:2022)
Cosmetics - Analytical methods - Determination of traces of mercury in cosmetics by atomic absorbtion spectrometry (AAS) cold vapour technology after pressure digestion (ISO 23821:2022)
This aim of this standard is to provide a process for the determination of mercury in cosmetics by means of cold vapour atomic adsorption (AAS) after pressure digestion.
The procedure was validated in 2015 by means of a multi laboratory study in combination with cold vapour AAS determination process for mercury with eight laboratories participating. Overall, seven samples representing different matrices (lipstick, tattoo colourant, body lotion, toothpaste, eyeshadow and water make-up) with varying mercury contents between 0,110 mg/kg and 5,84 mg/kg were analysed.
Kosmetische Mittel - Untersuchungsverfahren - Bestimmung von Quecksilberspuren in kosmetischen Mitteln durch Kaltdampf-Atomabsorptionsspektrometrie (AAS) nach Druckaufschluss (ISO 23821:2022)
Dieses Dokument legt ein Verfahren zur Bestimmung von Quecksilber in kosmetischen Mitteln mittels Kaltdampf-Atomabsorptionsspektrometrie (AAS) nach Druckaufschluss fest.
Cosmétiques - Méthodes d’analyse - Dosage des traces de mercure dans les cosmétiques par la technique de spectrométrie d’absorption atomique (SAA) de vapeur froide après digestion sous pression (ISO 23821:2022)
Le présent document spécifie une méthode de dosage du mercure dans les cosmétiques par spectrométrie d'absorption atomique (SAA) de vapeur froide après digestion sous pression.
Kozmetika - Analizne metode - Določevanje živega srebra v sledovih v kozmetičnih izdelkih z atomsko absorpcijsko spektrometrijo (AAS) s tehniko hladnih par po razklopu pod tlakom (ISO 23821:2022)
Cilj tega standarda je zagotoviti postopek za določanje živega srebra v kozmetičnih izdelkih z atomsko adsorpcijo s hladnimi parami (AAS) po razklopu pod tlakom.
Postopek je bil potrjen leta 2015 z večlaboratorijsko študijo v kombinaciji s postopkom določanja živega srebra s hladnimi parami AAS, v kateri je sodelovalo osem laboratorijev. Skupno je bilo analiziranih sedem vzorcev, ki so predstavljali različne matrice (šminka, barvilo za tetoviranje, losjon za telo, zobna pasta, senčilo za oči in vodica, ki se uporablja pri ličenju) z različnimi vsebnostmi živega srebra med 0,110 mg/kg in 5,84 mg/kg.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 23821:2023
01-april-2023
Kozmetika - Analizne metode - Določevanje živega srebra v sledovih v kozmetičnih
izdelkih z atomsko absorpcijsko spektrometrijo (AAS) s tehniko hladnih par po
razklopu pod tlakom (ISO 23821:2022)
Cosmetics - Analytical methods - Determination of traces of mercury in cosmetics by
atomic absorbtion spectrometry (AAS) cold vapour technology after pressure digestion
(ISO 23821:2022)
Kosmetische Mittel - Untersuchungsverfahren - Bestimmung von Quecksilberspuren in
kosmetischen Mitteln durch Kaltdampf-Atomabsorptionsspektrometrie (AAS) nach
Druckaufschluss (ISO 23821:2022)
Cosmétiques - Méthodes d’analyse - Dosage des traces de mercure dans les
cosmétiques par la technique de spectrométrie d’absorption atomique (SAA) de vapeur
froide après digestion sous pression (ISO 23821:2022)
Ta slovenski standard je istoveten z: EN ISO 23821:2022
ICS:
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
71.100.70 Kozmetika. Toaletni Cosmetics. Toiletries
pripomočki
SIST EN ISO 23821:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 23821:2023
---------------------- Page: 2 ----------------------
SIST EN ISO 23821:2023
EN ISO 23821
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2022
EUROPÄISCHE NORM
ICS 71.100.70
English Version
Cosmetics - Analytical methods - Determination of traces
of mercury in cosmetics by atomic absorbtion
spectrometry (AAS) cold vapour technology after pressure
digestion (ISO 23821:2022)
Cosmétiques - Méthodes d'analyse - Dosage des traces Kosmetische Mittel - Untersuchungsverfahren -
de mercure dans les cosmétiques par la technique de Bestimmung von Quecksilberspuren in kosmetischen
spectrométrie d'absorption atomique (SAA) de vapeur Mitteln durch Atomabsorptionsspektrometrie (AAS)
froide après digestion sous pression (ISO 23821:2022) Kaltdampftechnologie nach Druckaufschluss (ISO
23821:2022)
This European Standard was approved by CEN on 23 July 2022.
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, 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
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 23821:2022 E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 23821:2023
EN ISO 23821:2022 (E)
Contents Page
European foreword . 3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 23821:2023
EN ISO 23821:2022 (E)
European foreword
This document (EN ISO 23821:2022) has been prepared by Technical Committee ISO/TC 217
"Cosmetics" in collaboration with Technical Committee CEN/TC 392 “Cosmetics” the secretariat of
which is held by AFNOR.
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 2023, and conflicting national standards shall
be withdrawn at the latest by March 2023.
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/national committee. 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 23821:2022 has been approved by CEN as EN ISO 23821:2022 without any modification.
3
---------------------- Page: 5 ----------------------
SIST EN ISO 23821:2023
---------------------- Page: 6 ----------------------
SIST EN ISO 23821:2023
INTERNATIONAL ISO
STANDARD 23821
First edition
2022-08
Cosmetics — Analytical methods —
Determination of traces of mercury
in cosmetics by atomic absorbtion
spectrometry (AAS) cold vapour
technology after pressure digestion
Cosmétiques — Méthodes d’analyse — Dosage des traces de mercure
dans les cosmétiques par la technique de spectrométrie d’absorption
atomique (SAA) de vapeur froide après digestion sous pression
Reference number
ISO 23821:2022(E)
© ISO 2022
---------------------- Page: 7 ----------------------
SIST EN ISO 23821:2023
ISO 23821:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022
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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 23821:2023
ISO 23821:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus and equipment . 3
7 Procedure .4
7.1 General . 4
7.2 Preparation of samples . 4
7.3 Pressure assisted digestion . 4
7.3.1 General . 4
7.3.2 Preparation of sample by digestion — General case. 4
7.3.3 Preparation of sample by digestion — Specific cases . 4
7.3.4 Microwave digestion procedure . 5
7.3.5 Preparation of measurement solutions . . 5
7.4 Atomic absorption spectrometry (cold vapour AAS) . 6
7.4.1 Spectrometry settings . . . 6
7.4.2 Example for AAS determination using cold vapour technology . 6
7.5 Quality control of the analysis . . 6
8 Evaluation . 6
8.1 Calculation . 6
8.2 Limit of quantification . 7
8.3 Reliability of the method . 7
9 Test report . 7
10 Alternative stabilizing reagents . 8
11 Short-term stabilization when measuring with potassium permanganate solution .8
Annex A (informative) Performance of the method determined via ISO 5725 statistical
approach . 9
[4]
Annex B (informative) Common interlaboratory test results of ISO 23674 and this
document .12
Bibliography .15
iii
© ISO 2022 – All rights reserved
---------------------- Page: 9 ----------------------
SIST EN ISO 23821:2023
ISO 23821:2022(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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 217, Cosmetics, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 392, Cosmetics, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
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 2022 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 23821:2023
ISO 23821:2022(E)
Introduction
This document has been developed in parallel with ISO 23674. Knowing this, an interlaboratory test
using either one or the other method was performed on same tailor-made cosmetic products in order to
establish that both methods fulfilled the same requirements (see Annex B). This method was validated
[7]
by means of an interlaboratory test according to ISO 5725-2 using lipstick, body lotion, toothpaste
and eyeshadow, with a mercury concentration in the range of 0,110 mg/kg to 5,84 mg/kg. Statistical
characteristics regarding this interlaboratory test are provided in Annex A, Table A.1.
v
© ISO 2022 – All rights reserved
---------------------- Page: 11 ----------------------
SIST EN ISO 23821:2023
---------------------- Page: 12 ----------------------
SIST EN ISO 23821:2023
INTERNATIONAL STANDARD ISO 23821:2022(E)
Cosmetics — Analytical methods — Determination of
traces of mercury in cosmetics by atomic absorbtion
spectrometry (AAS) cold vapour technology after pressure
digestion
1 Scope
This document specifies a method for determination of mercury in cosmetics by means of cold vapour
atomic absorption spectrometry (AAS) with a prior pressure digestion.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
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:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
As a first step, the finished cosmetic product is digested in a closed vessel at high temperatures and
pressure using mineral acids. Pressure digestion is carried out at a temperature of 200 °C obtained by
means of microwave-assisted heating.
After digestion of the cosmetics, the concentration of mercury is determined by quantification using
the AAS cold vapour technology.
During mineralisation of the sample, it is not possible to dissolve all cosmetics without residues,
depending on their type and composition. In order to obtain comparable results, it is absolutely
mandatory to conform with the conditions specified for this method.
The measurement solution is transferred to the reaction vessel of the mercury analysis unit. From
there, mercury is rinsed out into the cuvette of the AAS instrument with the help of a carrier gas flow
after reduction with divalent tin or sodium borohydride. Absorption at the mercury line of 253,7 nm is
used as a measure for mercury concentration in the cuvette. By using a gold/platinum mesh (amalgam
technology) for concentration of the rinsed-off mercury prior to measurement in the cuvette, it is
possible to achieve lower limits of quantification (LOQs).
5 Reagents
The reagents and the water used shall be free of mercury to such an extent that the analysis is not
impaired. Unless specified otherwise, pure-analysis chemicals shall be used, and solutions are
1
© ISO 2022 – All rights reserved
---------------------- Page: 13 ----------------------
SIST EN ISO 23821:2023
ISO 23821:2022(E)
understood to be aqueous solutions. Use water conforming to Grade 1 of ISO 3696 (conductivity below
0,1 µS/cm at 25 °C).
5.1 Hydrochloric acid, minimum mass fraction w = 30 %, density = 1,15 g/ml, suitable for elemental
analysis.
5.2 Nitric acid, minimum w = 65 %, density = 1,4 g/ml, suitable for elemental analysis.
5.3 Diluted nitric acid, produced by mixing nitric acid (5.2) at a ratio of approximately 1 + 9 with
water respectively.
5.4 Reducing agents, for example tin(II) chloride or sodium borohydride.
Alternating operation with both reducing agents (5.4.1 and 5.4.2) is not recommended. For this purpose,
the appropriate information from the manufacturer of the instrument shall be followed.
The mass concentrations of the reducing agent solutions can vary, depending on the system. The
corresponding data of the manufacturer of the instrument shall be conformed with.
5.4.1 Tin(ll) chloride solution, for example mass concentration ρ = 100 g/l.
Weigh 50 g tin(ll) chloride, SnCI ·2H O in a 500 ml volumetric flask, dissolve in approximately 100 ml
2 2
hydrochloric acid (5.1), and fill up to 500 ml with water. The solution shall be freshly prepared prior to
use.
5.4.2 Sodium borohydride solution, for example ρ = 30 g/l.
Dissolve 3 g of sodium borohydride and 1 g of sodium hydroxide pellets in water and fill up with 100 ml
water. The solution shall be freshly prepared every day and filtered prior to use.
WARNING — Compliance with the safety instructions is mandatory when working with sodium
borohydride. Sodium borohydride forms hydrogen when combined with water and especially
on reaction with acids, which can result in an explosive air/hydrogen mixture. A fixed exhaust
system shall be installed/present in the area where measurements are carried out.
5.5 Stabilization
The standard, calibration and sample digestion solutions are stabilized with hydrochloric acid (5.1). It
is recommended to set a hydrochloric acid concentration of around ω = 1 % in the solutions. Alternative
stabilizing reagents can also be used (see Clause 10).
5.6 Mercury stock solution, mercury ρ = 1 000 mg/l.
The stock solution is commercially available. It is recommended to use certified stock solutions.
5.7 Mercury standard solutions
Dilute the stock solution to the concentrations required for calibration and add the necessary amount
of stabilisation reagent (5.5). In doing so, select concentrations that the linear range of the reference
function is not exceeded. It is recommended to use at least three (3) standard solutions with different
concentrations.
The acid concentration in the standard solutions shall correspond to the acid concentration of the
measurement solution. Mercury standard solutions have a rather short shelf life, even at higher
concentrations; therefore, they shall be freshly prepared every day.
2
© ISO 2022 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 23821:2023
ISO 23821:2022(E)
5.8 Calibration blank solution
The calibration blank solution shall contain water, the same amount of stabilisation reactant as the
mercury standard solutions (5.7) per litre and the quantities of nitric acid (5.2) and hydrochloric acid
(5.1) that correspond to the acid concentrations in the measurement solution.
6 Apparatus and equipment
For the determination of mercury all apparatus and equipment that come into direct contact with the
sample and the solutions used shall be thoroughly pre-treated to ensure minimisation of contamination.
The following steps are recommended for cleaning: Rinse with drinking water, treat with a scouring
agent solution, repeat rinsing with drinking water and soak in diluted nitric acid (5.3) over night or
a prolonged period. Prior to use, rinse the apparatus with ultrapure water and dry. Steaming of
chemically inert vessels (e.g. made of quartz glass) using nitric acid (5.2) is an effective cleaning method
and is regularly used in element trace analysis. To prevent contamination and adsorption, only use lab
materials made with borosilicate or quartz glass.
6.1 Digestion vessels.
Use commercially available, safety-tested pressure vessels and inserts made of acid resistant and, low-
contamination materials. The assembled vessels shall be able to safely withstand temperatures up to
at least 200 °C and pressures up to at least 40 bar. The specific size of the vessels is not mandatory and
depends on the used type of microwave.
Dedicated digestion vessels are recommended for the digestion of cosmetic samples, which may have
high levels of elements to be determined. To avoid memory effects, perform a blank digestion to clean
vessels after digesting highly loaded samples, before digesting sequent samples.
6.2 Microwave assisted digestion instruments.
Microwave-heated systems shall be equipped with a temperature measurement unit, which
simultaneously regulates the power control of the microwave. Reliable temperature measurement
is obtained, for example, through measurement sensors inserted into the pressure vessel. Only use
microwave-assisted digestion instruments equipped with temperature sensors and calibrate the
temperature sensor before use.
6.3 Membrane filter, 0,45 µm pore size.
The membrane filter used shall be inert with regard to the acid concentration of the measurement
solution and shall not bring any contamination into the measurement solution or adsorption of the
analytes. Several types of membrane material are commercially available (e.g. PTFE, PP) and their fit
for purpose shall be verified by means of appropriate measurements (e.g. blanks, QC samples).
6.4 Atomic absorption spectrometer, optionally available with background correction and
including accessories for cold vapour technology or amalgam technology.
Flow injection systems can be used as an alternative of manual processes.
6.5 Element-specific light for mercury
Measurement at 253,7 nm.
3
© ISO 2022 – All rights reserved
---------------------- Page: 15 ----------------------
SIST EN ISO 23821:2023
ISO 23821:2022(E)
7 Procedure
7.1 General
WARNING — The use of this document can involve hazardous materials, operations and
equipment. This document does not address all the safety risks associated with its use. It is the
responsibility of the user of this document to take appropriate measures for ensuring the safety
and health of the personnel prior to application of the document.
During all process steps it shall be ensured that there are no losses of analyte and that contamination is
kept as low as possible.
7.2 Preparation of samples
Before the digestion of the sample, a suitable preparation shall be carried out (e.g. homogenizing, mixing,
[13]
crushing ). After homogenization thoroughly clean the devices in order to rule out contamination of
the subsequent sample. The sample preparation step shall ensure a homogeneous starting material for
a test portion quantity.
7.3 Pressure assisted digestion
7.3.1 General
WARNING 1 Depending on the type of reactivity of the sample, it can be required to weigh in lower quantities
than specified in 7.3.2 in order to prevent extreme reactions or explosions. It shall be taken into account that
digestion of samples with high carbon contents (e.g. carbohydrates, fats, oils, waxes) can cause explosions.
Alcohols or solvents in combination with concentrated nitric acid can cause delayed severe reactions already
at room temperature. Therefore, it is highly recommended to gently evaporate all volatile components before
adding the acid (7.3.3).
WARNING 2 Samples that are not covered by acid can cause local overheating of the digestion vessel and thus
lead to local melting and subsequent bursting of the digestion vessel. Prior to digestion, ensure that the entire
sample is fully covered by the acid mixture.
Temperature and pressure inside the vessels shall be controlled to ensure a proper digestion. To avoid
differences in temperature and pressure among vessels, one should only digest samples with similar
composition in the same microwave-assisted digestion batch.
7.3.2 Preparation of sample by digestion — General case
Precisely weigh about 200 mg of sample into a digestion vessel.
Add 1 ml of water and thoroughly mix with a shaking device until the sample is completely suspended
in the water.
Add 5 ml nitric acid (5.2) to the mixture and mix again. The sample should be completely covered
with the solution. Allow the mixture to rest in a closed digestion vessel to ensure that the preliminary
reaction takes place. Depending on the reactive behaviour of the sample the duration of the preliminary
reaction can require resting periods of 30 min up to overnight.
Then add 1 ml of hydrochloric acid (5.1) and briefly mix. After addition of the hydrochloric acid, the
pressure vessel shall be closed and sealed immediately to make sure that the formed chlorine gas is
available for the reaction and does not evaporate.
7.3.3 Preparation of sample by digestion — Specific cases
— For highly water-based cosmetic products, such as lotion, milky lotion, cleanser or micellar water, a
test portion could reach 400 mg. In this case no addition of water is required before addition of acids
(7.3.2).
4
© ISO 2022 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 23821:2023
ISO 23821:2022(E)
— For all the other specific cases, test portion can be adapted but the ratio between test portion and
acid volumes (7.3.2) shall not be changed.
In case of products with a significant content of volatile components, for safety reasons, it is highly
recommended to remove volatile components by carefully heating up the sample (e.g. in a water bath at
60 °C) after weighing the sample in the digestion vessel, but prior to the addition of the acid. The loss of
volatile components should be determined at the end of the process. In this context, special care shall
be taken to prevent losses of the specific elements.
Due to sample heterogeneity concern, a test portion below 100 mg is not recommended.
7.3.4 Microwave digestion procedure
WARNING 1 During all steps of the digestion process, the manufacturer’s safety information shall be
accurately followed.
7.3.4.1 Process the samples using, for example, a three-step heating program:
a) ramp the heat up from room temperature to 200 °C in, for example, 30 min;
b) hold the temperature at 200 °C for 30 min;
c) cool down to 50 °C, before removing the vessels from the microwave.
It is mandatory to maintain a temperature of 200 °C for 30 min to obtain comparable results, since
complete digestion
...
SLOVENSKI STANDARD
oSIST prEN ISO 23821:2021
01-marec-2021
Kozmetika - Analizne metode - Določevanje živega srebra v kozmetičnih izdelkih z
atomsko absorpcijsko spektrometrijo (AAS) s tehniko hladnih par po razklopu pod
tlakom (ISO/DIS 23821:2021)
Cosmetics - Analytical methods - Determination of traces of mercury in cosmetics by
atomic absorbtion spectrometry (AAS) cold vapour technology after pressure digestion
(ISO/DIS 23821:2021)
Kosmetische Mittel - Untersuchungsverfahren - Bestimmung von Quecksilberspuren in
kosmetischen Mitteln durch Atomabsorptionsspektrometrie (AAS) Kaltdampftechnologie
nach Druckaufschluss (ISO/DIS 23821:2021)
Cosmétiques - Méthodes d’analyse - Dosage des traces de mercure dans les
cosmétiques par la technique de spectrométrie d’absorption atomique (SAA) de vapeur
froide après digestion sous pression (ISO/DIS 23821:2021)
Ta slovenski standard je istoveten z: prEN ISO 23821
ICS:
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
71.100.70 Kozmetika. Toaletni Cosmetics. Toiletries
pripomočki
oSIST prEN ISO 23821:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 23821:2021
---------------------- Page: 2 ----------------------
oSIST prEN ISO 23821:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 23821
ISO/TC 217 Secretariat: ISIRI
Voting begins on: Voting terminates on:
2021-02-04 2021-04-29
Cosmetics — Analytical methods — Determination of
traces of mercury in cosmetics by atomic absorbtion
spectrometry (AAS) cold vapour technology after pressure
digestion
ICS: 71.100.70
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 23821:2021(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
---------------------- Page: 3 ----------------------
oSIST prEN ISO 23821:2021
ISO/DIS 23821:2021(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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 23821:2021
ISO/DIS 23821:2021(E)
Contents Page
European foreword .iv
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Reagents . 2
5 Apparatus and equipment . 3
6 Procedure. 4
6.1 General . 4
6.2 Preparation of samples . 4
6.3 Pressure assisted digestion . 4
6.3.1 Preparation of sample by digestion – General case . 4
6.3.2 Preparation of sample by digestion – Specific cases . 4
6.3.3 Microwave digestion procedure . 5
6.3.4 Preparation of measurement solutions . 5
6.4 Atomic absorption spectrometry (cold vapour AAS) . 5
6.4.1 Spectrometry settings . 5
6.4.2 Example for AAS determination using cold vapour technology . 6
6.5 Quality control of the analysis . 6
7 Evaluation . 6
7.1 Calculation . 6
7.2 Determination limit . 7
7.3 Reliability of the method . 7
8 Test report . 7
9 Alternative stabilizing reagents. 7
10 Short-t erm stabilization when measuring with potassium permanganate solution .8
Annex A (normative) Performance of the method determined via ISO 5725 statistical approach.9
Annex B (normative) ISO 23674 and ISO 23821 common interlaboratory test results .12
Bibliography .14
© ISO 2021 – All rights reserved iii
---------------------- Page: 5 ----------------------
oSIST prEN ISO 23821:2021
ISO/DIS 23821:2021(E)
European foreword
This document (prEN 23821:2020) has been prepared by Technical Committee CEN/TC 392 “Cosmetics”,
the secretariat of which is held by AFNOR.
This document is a working document.
iv © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 23821:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 23821:2021(E)
Cosmetics — Analytical methods — Determination of
traces of mercury in cosmetics by atomic absorbtion
spectrometry (AAS) cold vapour technology after pressure
digestion
1 Scope
This European standard specifies a process for determination of mercury in cosmetics by means of
cold vapour atomic absorption (AAS) with a prior pressure digestion. This process was validated by
means of an interlaboratory test according to ISO 5725-2 [6] using e.g. lipstick, body lotion, toothpaste
and eyeshadow, with a mercury concentration in the range of 0,110 mg/kg to 5,84 mg/kg. Statistical
characteristics regarding this interlaboratory test are provided in Annex A, Table A.1.
This standard has been developed in parallel with ISO 23674. Knowing this, an interlaboratory test
using either one or the other method was performed on same tailor-made cosmetic products in order to
establish that both methods fulfilled the same requirements (see Annex B).
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 23674, Cosmetics — Analytical Methods — Determination of mercury in cosmetics by integrated
mercury analytical systems
3 Principle
As a first step, the finished cosmetic product is digested in a closed container at high temperatures and
pressure using mineral acids. Pressure digestion is carried out at a temperature of 200 °C obtained by
means of microwave-assisted heating.
After digestion of the cosmetics the concentration of mercury is determined by quantification using the
AAS cold vapour technology.
During mineralisation of the sample it is not possible to dissolve all cosmetics without residues,
depending on their type and composition. In order to obtain comparable results, it is absolutely
mandatory to comply with the conditions specified for this process.
The measurement solution is transferred to the reaction container of the mercury analysis unit. From
there, mercury is rinsed out into the cuvette of the AAS instrument with the help of a carrier gas flow
after reduction with divalent tin or sodium borohydride. Absorption at the mercury line of 253,7 nm is
used as a measure for mercury concentration in the cuvette. By using a gold/platinum mesh (amalgam
technology) for concentration of the rinsed-off mercury prior to measurement in the cuvette it is
possible to achieve lower LOQs.
© ISO 2021 – All rights reserved 1
---------------------- Page: 7 ----------------------
oSIST prEN ISO 23821:2021
ISO/DIS 23821:2021(E)
4 Reagents
The reagents and the water used shall be free of mercury to such an extent that the analysis is not
impaired. Unless specified otherwise, pure-analysis chemicals shall be used and solutions are
understood to be aqueous solutions. Use water conforming to Grade 1 of ISO 3696 (conductivity below
0,1 µS/cm at 25 °C).
4.1 Hydrochloric acid, minimum w = 30 %, density = 1,15 g/ml.
4.2 Nitric acid, minimum w = 65 %, density = 1,4 g/ml.
4.3 Diluted nitric acid, produced by mixing nitric acid (4.2) with water at a ratio of approximately
1 + 9 parts respectively.
4.4 Reducing agents, for example tin(II) chloride or sodium borohydride.
Alternating operation with both reducing agents (4.4.1 and 4.4.2) is not recommended. For this purpose,
the appropriate information from the manufacturer of the instrument shall be followed.
The mass concentrations of the reducing agent solutions can vary, depending on the system. The
corresponding data of the manufacturer of the instrument shall be complied with.
4.4.1 Tin(ll) chloride solution, for example mass concentration ρ = 100 g/l.
Weigh 50 g tin(ll) chloride, SnCI ·2H 0 in a 500 ml volumetric flask and dissolve in approximately
2 2
100 ml hydrochloric acid (4.1) and dilute to the mark with water. The solution shall be freshly prepared
prior to use.
4.4.2 Sodium borohydride solution, for example ρ = 30 g/l.
Dissolve 3 g of sodium borohydride and 1 g of sodium hydroxide pellets in water and dilute with 100 ml
water. The solution shall be freshly prepared every day and filtered prior to use.
WARNING — Compliance with the safety instructions is mandatory when working with sodium
borohydride. Sodium borohydride forms acids when combined with hydrogen, which can result
in an explosive air/hydrogen mixture. A fixed exhaust system shall be installed/present in the
area where measurements are carried out.
4.5 Stabilization
The standard, calibration and sample digestion solutions are stabilized with hydrochloric acid (4.1). It
is recommended to set a hydrochloric acid concentration of around ω = 1% in the solutions. Alternative
stabilizing reagents can also be used (see Clause 9).
4.6 Mercury stock solution, mercury mass concentration of ρ = 1 000 mg/l.
The stock solution is commercially available. It is recommended to use certified stock solutions. As
an alternative, the stock solution prepared from mercury(II) oxide can be stabilised using potassium
[1] [3]
dichromate or solution prepared from mercury(II) chloride can be stabilised using nitric acid (4.2) .
4.7 Mercury standard solutions
Dilute the stock solutions to the concentrations required for calibration and add the necessary amount
of stabilisation reagent (4.6), In doing so, select concentrations that the linear range of the reference
2 © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
oSIST prEN ISO 23821:2021
ISO/DIS 23821:2021(E)
function is not exceeded. It is recommended to use at least 3 standard solutions with different
concentrations.
The acid concentration in the standard solution shall correspond to the acid concentration of the
measurement solution. Mercury standard solutions have a rather short shelf life, even at higher
concentrations; therefore, they shall be freshly prepared every day.
4.8 calibration blank solution
The calibration blank solution shall contain water, the same amount of stabilisation reactant as the
mercury standard solutions (4.7) per litre and the quantities of nitric acid (4.2) and hydrochloric acid
(4.1) that correspond to the acid concentrations in the measurement solution.
5 Apparatus and equipment
For the determination of mercury all apparatus and equipment that come into direct contact with the
sample and the solutions used shall be thoroughly pre-treated to ensure minimisation of contamination.
The following steps are recommended for cleaning: Rinse with drinking water, treat with a scouring
agent solution, repeat rinsing with drinking water and soak in diluted nitric acid (4.3) over night or a
prolonged period. Prior to use, rinse the apparatus with ultrapure water and dry. Steaming of chemically
inert vessels and containers (e.g. made of quartz glass) using nitric acid (4.2) is an effective cleaning
method and is regularly used in element trace analysis. To prevent contamination and adsorption, do
not use lab materials made with borosilicate glass.
5.1 Digestion vessels.
Use commercially available, safety-tested pressure vessels and inserts made of acid resist and, low-
contamination materials. The assembled vessels shall be able to safely withstand temperatures up to at
least 200 °C and pressures up to at least 40 bar.
NOTE Dedicated digestion vessels are recommended for the digestion of cosmetic samples, which may have
high levels of elements to be determined. To avoid memory effects, perform a blank digestion to clean vessels
after digesting highly loaded samples, before digesting sequent samples.
5.2 Microwave assisted digestion instruments.
Microwave-heated systems shall be equipped with a temperature measurement unit, which
simultaneously regulates the power control of the microwave. Reliable temperature measurement is
obtained e.g. through measurement sensors inserted into the pressure vessel. Only use microwave-
assisted digestion instruments equipped with temperature sensors and calibrate the temperature
sensor before use.
5.3 Membrane filter, pore size: 0,45 µm.
The membrane filter used shall be inert with regard to the acid concentration of the measurement
solution and shall not bring any contamination into the measurement solution or adsorption of the
analytes. Several types of membrane material are commercially available (e.g. PTFE, PP) and their fit
for purpose shall be verified by means of appropriate measurements (e.g. blanks, QC samples).
5.4 Atomic absorption spectrometer, optionally available with background compensation function
and including accessories for cold vapour technology or amalgam technology.
Flow injection systems can be used as an alternative of manual processes.
5.5 Element-specific light for mercury
Measurement at 253,7 nm.
© ISO 2021 – All rights reserved 3
---------------------- Page: 9 ----------------------
oSIST prEN ISO 23821:2021
ISO/DIS 23821:2021(E)
6 Procedure
6.1 General
WARNING — The use of this standard can involve hazardous materials, operations and
equipment. This standard does not address all the safety problems associated with its use. It
is the responsibility of the user of this standard to take appropriate measures for ensuring the
safety and health of the personnel prior to application of the standard and to fulfil statutory
requirements for this purpose.
During all process steps it shall be ensured that there are no losses of analyte and that contamination is
kept as low as possible.
6.2 Preparation of samples
Before the digestion of the sample a suitable preparation needs to be carried out (e.g. homogenizing,
[13]
mixing, crushing ). After homogenization thoroughly clean the devices in order to rule out
contamination of the subsequent sample. The sample preparation step shall ensure a homogeneous
starting material for a weighed sample quantity.
6.3 Pressure assisted digestion
WARNING 1 Depending on the degree or reactivity of the sample, it may be required to weigh in lower
quantities than specified in Section 6.3.1 in order to prevent extreme reactions or explosions. It shall be taken
into account that digestion of samples with high carbon contents (e.g. carbohydrates, fats, oils, waxes) may cause
explosions. Alcohols or solvents in combination with concentrated nitric acid may cause delayed severe reactions
already at room temperature. Therefore it is highly recommended to gently evaporate all volatile components
before adding the acid (Section 6.3.2).
WARNING 2 Samples that are not covered by acid can cause local overheating of the digestion vessel and thus
lead to local melting and subsequent bursting of the digestion container. Prior to digestion, ensure that the entire
sample is fully covered by the acid mixture.
Temperature and pressure inside the vessels shall be carefully controlled to ensure a proper digestion.
To avoid differences in temperature and pressure among vessels, one should only digest samples with
similar composition in the same microwave-assisted digestion batch.
6.3.1 Preparation of sample by digestion – General case
Precisely weigh about 200 mg of sample into a digestion container.
Add 1 ml of water and thoroughly mix with a shaking device until the sample is completely suspended
in the water.
Add 5 ml nitric acid (4.2) to the mixture and mix again. The sample should be completely covered
with the solution. Allow the mixture to rest in a closed digestion vessel to ensure that the preliminary
reaction takes place. Depending on the reactive behaviour of the sample the duration of the preliminary
reaction can require resting periods of 30 minutes up to overnight.
Then add 1 ml of hydrochloric acid (4.1) and briefly mix. After addition of the hydrochloric acid, the
pressure vessel shall be closed and sealed immediately to make sure that the formed chlorine gas is
available for the reaction and does not evaporate.
6.3.2 Pr
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.