kSIST FprEN ISO 21392:2021

SLOVENSKI STANDARD
oSIST prEN ISO 21392:2020
01-junij-2020
Kozmetika - Analizne metode - Določevanje sledov težkih kovin v končnih
kozmetičnih izdelkih z masno spektrometrijo z induktivno sklopljeno plazmo
(ICP/MS) (ISO/DIS 21392:2020)

Cosmetics - Analytical Methods - Measurement of traces of heavy metals in cosmetic

Schwermetallen in fertigen kosmetischen Mitteln mittels ICP-MS (ISO/DIS 21392:2020)

Cosmétiques - Méthodes analytiques - Détermination de traces de métaux lourds dans

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Cosmétiques — Méthodes analytiques — Détermination de traces de métaux lourds dans les produits finis

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

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

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

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

3 Principle ........................................................................................................................................................................................................................ 1

4 Reagents ........................................................................................................................................................................................................................ 1

5 Apparatus and equipment .......................................................................................................................................................................... 2

5.1 Digestion vessels ................................................................................................................................................................................... 2

5.2 Microwave-assisted digestion instruments ................................................................................................................... 2

5.3 Membrane filter, 0,45 µm pore size ....................................................................................................................................... 2

5.4 ICP-MS ............................................................................................................................................................................................................ 2

6 Preparation of standards solutions .................................................................................................................................................. 3

6.1 Diluted nitric acid, produced by mixing nitric acid (4.2) with pure water (4.1) at a

ratio of approximately 1+9 parts respectively. ............................................................................................................ 3

6.2 Diluting solution .................................................................................................................................................................................... 3

6.3 Internal Standard solutions. ........................................................................................................................................................ 3

6.3.1 Rhodium(*) standard solution, 1 mg/l ......................................................................................................... 3

6.3.2 Lutetium(*) standard solution, 1 mg/l ......................................................................................................... 3

6.4 Standard solutions ............................................................................................................................................................................... 4

6.4.1 High concentration mixed standard solution, 10 mg/l ................................................................... 4

6.4.2 Low concentration mixed standard solution, 0.1 mg/l .................................................................. 4

6.5 Calibration blank solution ............................................................................................................................................................. 4

6.6 Calibration solutions .......................................................................................................................................................................... 4

7 Procedure..................................................................................................................................................................................................................... 5

7.1 General ........................................................................................................................................................................................................... 5

7.2 Preparation of samples .................................................................................................................................................................... 5

7.3 Pressure assisted digestion .......................................................................................................................................................... 5

7.3.1 Preparation of Sample by Digestion – General case .......................................................................... 5

7.3.2 Preparation of Sample by Digestion – Specific cases ........................................................................ 6

7.3.3 Microwave digestion procedure ......................................................................................................................... 6

7.3.4 Preparation of measurement solutions ....................................................................................................... 6

7.4 Inductively Coupled Plasma Mass Spectrometry ...................................................................................................... 7

7.4.1 ICP-MS operating conditions ................................................................................................................................. 7

7.4.2 Quantification of the analytes by ICP-MS .................................................................................................... 7

7.5 Quality control of the analysis ................................................................................................................................................... 8

7.5.1 During the digestion ..................................................................................................................................................... 8

7.5.2 During the analysis ........................................................................................................................................................ 9

7.5.3 Example of ICP-MS sequence ................................................................................................................................ 9

8 Calculation ...............................................................................................................................................................................................................10

9 Method performance ....................................................................................................................................................................................10

Annex A Performance of the method determined by the accuracy profile methodology ........................12

Annex B (Informative) Information on the Evaluation of the method via ISO 5725 statistical

approach (*) ...........................................................................................................................................................................................................15

Bibliography .............................................................................................................................................................................................................................23

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

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

Any trade name used in this document is information given for the convenience of users and does not

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/

Any feedback or questions on this document should be directed to the user’s national standards body. A

This standard specifies an analytical procedure for determination of trace elements (Chromium,

Cobalt, Nickel, Arsenic, Cadmium, Antimony and Lead) in finished cosmetics products by Inductively

Coupled Plasma Mass Spectrometry (ICP-MS) after pressure digestion of the sample. This type of

analytical procedure is widely described in other areas such as environment, food and

The aim of this standard is to provide a method of quantification of heavy metal trace elements in

cosmetic products that consumers might be exposed to in their usage. In the sample preparation

procedure, nitric acid/hydrochloric acid mixture is used and most of the cosmetic ingredients are

digested allowing heavy metal trace elements to be solubilized for measurement. Some cosmetic

inorganic ingredients such as silica or titanium dioxide might not be completely digested under the

conditions of this standard and heavy metal trace elements confined in such ingredients might not

be fully extracted. However, the heavy metal trace elements trapped in these inorganic materials

are considered less relevant for the evaluation of the exposure level of consumers to unwanted trace

elements. The use of ICP-MS ensures reliable measurement of trace elements due to its proven high

This analytical methodology can be applied to many other elements but this standard refers only to

the above listed trace elements and it is to the responsibility of the analyst to prove that it fits for

that purpose. In order to obtain comparable results, it is absolutely mandatory to comply with all the

Trace elements in cosmetic products are quantified by ICP-MS measurement of the solutions resulting

from digestion of the cosmetic products. Digestion takes place with mineral acids in sealed vessels

The reagents and the water used shall be free of the elements to be determined to such an extent

that the results are not impaired. Unless specified otherwise, solutions are understood to be aqueous

4.1 Ultrapure water, conductivity below 0,1µS/cm-1 at 25°C according to Type 1 water specifications

For storage and stability conditions of the internal standard stock solutions, follow the specifications of

4.5 Analytes stock solutions (Chromium, Cobalt, Nickel, Arsenic, Cadmium, Antimony and Lead),

Commercially available single element or mixed stock solutions can be used. For this 2 cases, the used

stock solutions shall not contain other elements that could interfere with the analytes to be quantified.

4.6 Commercially available ICP-MS Tune solution, containing e.g. Ce, Co, Li, Mg, Tl and Y (1 µg/l)

All apparatus and equipment that come into direct contact with sample or solutions shall be pre-cleaned

with dilute nitric acid (6.1) and rinsed with ultrapure water (4.1) to ensure the lowest analyte background.

To prevent contamination and adsorption, do not use lab materials made with borosilicate glass.

Use commercially available, safety-tested pressure vessels and inserts made of acid-resistant, low-

contamination materials. The assembled vessels shall be able to safely withstand temperatures up to at

For determination of antimony, use only digestion containers with minimal surface roughness to

prevent its adhesion to the container surface . Quartz containers are recommended because

they are usually more resistant to attrition. However, Teflon vessels without any scratch or damage on

their inner surface or any deposits are appropriate. Scratched or etched containers should not be used.

If there is any question regarding possible adsorption of antimony on vessels’ walls, test for surface

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

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

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 (PTFE, PP…) and their fit for

purpose must be verified by means of appropriate measurements (blanks, QC samples…).

Mass spectrometer with inductively coupled argon plasma is composed of a sample introduction and

an atomisation system, as well as an instrument control and evaluation unit. To prevent interferences

with the masses of the elements of chromium, nickel, arsenic and cadmium, use of a mass spectrometer

that is capable of compensating or minimising such interferences (e.g. collision and/or reaction cell,

resolution above 3000, alternatively corrective equations for higher concentrations).

For all the solutions, the terminology “part” in the standard refers to either volume or weight. That

means that standards and samples can be diluted by volume or weight. However, it should be consistent

6.1 Diluted nitric acid, produced by mixing nitric acid (4.2) with pure water (4.1) at a ratio

The composition of the diluting solution must have the same acid composition (total content and acid

ratio) as the Analytical Solution (the diluted digest solution). This solution should contain:

The internal standards (IS) selected should cover all the mass range of the considered analytes and

have similar ionisation energy to the trace element for which it is used for correction purposes. It shall

also be checked that the native concentration of the internal standards in the sample to be analysed is

“Rhodium and Lutetium have proved to be well suited as internal standards (IS). Samples should be

checked for negligible native concentrations of the IS and that the IS are not interfered with by sample

Rhodium is suitable for determination of Chromium, Cobalt, Nickel, Arsenic, Cadmium and Antimony,

whereas Lutetium is suitable for determination of Lead. Alternatively, other elements may be used (for

example Indium or Iridium). Scandium, however, is not suitable as an IS due to Calcium interferences.

An IS with a mass (m/z) below 100 is not recommended because it may suffer from interferences from

NOTES : - Internal standard solutions may be added in each sample and calibration solution at the same

- the concentration of the internal standard solutions must be included in the range 1 to 2 mg/l. In the following

Dilute the Rhodium stock solution (4.4.1) 1 + 999 with diluting solution (6.2). This internal standard

Dilute the Lutetium stock solution (4.4.2) 1 + 999 with diluting solution (6.2). This internal standard

The concentrations of these standard solutions are examples and shall be adjusted to the specific

— in the case of single analyte stock solutions, 1 part of each of these 7 solutions to 93 parts of the

— in the case of mixed stock solution, add 1 part of this solution to 99 parts of the diluting solution (6.2).

Dilute 100 times the high concentration standard solution (5.4.1) by adding 1 part of this solution to

99 parts of the diluting solution (6.2). This low standard solution is stable at room temperature for

The calibration blank solution corresponds to the matrix solution without any analyte of interest.

Generally, it corresponds to the diluting solution with the suitable concentration of the appropriate

Mixed calibration solutions are prepared by diluting the low concentration mixed standard solution

(6.4.2) with the diluting solution (6.2) to levels in the linear range of the instrument and within the

targeted concentration range. Include a suitable concentration of the appropriate internal standards,

or add on line the internal standards by means of pumping into the sample flow through a Y-fitting.

At least 3 calibration solutions with various concentrations should be prepared. These calibration

Examples of preparation procedure of calibration solutions are detailed in Table 1a (with addition of

the internal standards in all the calibration solutions) and Table 1b (with on line addition of the internal

Table 1a — Example of calibration solutions of the ICP-MS – addition of the internal standards

Calibration solution Part of low Part of Rhodi- Part of Luteti- Part of the Analyte conc.

Table 1b — Example of calibration solutions of the ICP-MS – online addition of the internal

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

Homogenize the samples by means of suitable devices. After homogenization thoroughly clean the

devices in order to rule out contamination of the subsequent sample. The sample preparation step shall

WARNING 1 Depending on the degree or reactivity of the sample, it may be required to weigh in lower

quantities than specified in Section 7.3.1 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

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

Temperature and pressure into the vessels must be carefully controlled to ensure a proper digestion

(section 5.2.). To avoid differences in temperature and pressure among vessels, one should only digest

Add 1 ml of water (4.1) and thoroughly mix with a shaking device until the sample is completely

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 behavior of the sample the duration of the preliminary

Add then 1 ml of hydrochloric acid (4.3) 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

• For highly water-based cosmetic products, such as lotion, milky lotion, cleanser, micellar water, a

sample mass could reach 400 mg. In this case no addition of water is required before addition of

• For all the other specific cases, sample mass can be adapted but the ratio between sample mass and

In case of high volatile content products, it is highly recommended for safety reason to completely