prEN 17845

Construction products: Assessment of release of dangerous substances - Determination of biocide residues using LC-MS/MS

This document describes a method for the determination of the content of biocides in construction products, (either finished (dried) or in a ready-to-use state) and in eluates thereof, using liquid chromatography and tandem mass spectrometric detection (LC-MS/MS).
For content analysis liquid chromatography with UV-detection can also be used, if sufficient sensitivity and selectivity is ensured (see Annex A).
The method in this document is validated for the product types listed in Annex D. For eluate analysis quantification limits of 0,1 µg/l can be achieved.

Bauprodukte: Bewertung der Freisetzung von gefährlichen Stoffen - Bestimmung von Biozid-Rückständen mittels LC-MS/MS

Dieses Dokument beschreibt ein Verfahren für die Bestimmung des Gehalts an Bioziden in Bauprodukten (entweder im fertigen (getrockneten) oder im gebrauchsfertigen Zustand) und in deren Eluaten mittels Flüssigchromatographie und Tandem-Massenspektrometrie (LC MS/MS).
Für die Analyse des Gehalts kann auch Flüssigchromatographie mit UV-Detektion verwendet werden, wenn eine ausreichende Empfindlichkeit und Selektivität sichergestellt ist (siehe Anhang A).
Das in diesem Dokument beschriebene Verfahren ist für die in Anhang D aufgeführten Produkttypen validiert. Bei der Analyse von Eluaten können Quantifizierungsgrenzen von 0,1 µg/l erreicht werden.

Produits de construction - Évaluation des émissions de substances dangereuses - Détermination de la teneur en biocides par LC-MS/MS

Le présent document décrit une méthode pour la détermination de la teneur en biocides dans les produits de construction [(finis (séchés) ou prêts à l'emploi] et dans leurs éluats, par chromatographie en phase liquide et détection par spectrométrie de masse en tandem (LC-MS/MS).
Pour l'analyse de contenu, la chromatographie en phase liquide avec détection d'UV peut également être utilisée, si une sensibilité et une sélectivité suffisantes sont assurées (voir l'Annexe A).
La méthode décrite dans le présent document est validée pour les types de produits énumérés à l'Annexe D. Pour l'analyse des éluats, des limites de quantification de 0,1 µg/l peuvent être atteintes.

Gradbeni proizvodi - Ocenjevanje sproščanja nevarnih snovi - Določevanje ostankov biocidov s tekočinsko kromatografijo in tandemsko masno spektrometrijo (LC-MS/MS)

General Information

• Status: Not Published
• Publication Date: 11-Apr-2021
• Withdrawal Date: 11-Jul-2021
• ICS: 91.100.01 - Construction materials in general
• Technical Committee: CEN/TC 351 - Construction Products - Assessment of release of dangerous substances
• Drafting Committee: CEN/TC 351/WG 5 - Content and eluate analysis in construction products
• Current Stage: 4060 - Closure of enquiry - Enquiry
• Start Date: 28-Jul-2022
• Due Date: 08-Oct-2019
• Completion Date: 28-Jul-2022
• Directive: 305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Mandate: M/366 - Concerning the execution of standardisation work for the development of horizontal standardised assessment methods for harmonized approcaches relating to dangerous substances under the construction products directive (CPD)
• Ref Project: oSIST prEN 17845:2022 - Construction products: Assessment of release of dangerous substances - Determination of biocide residues using LC-MS/MS

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 17845:2022
01-junij-2022
Gradbeni proizvodi - Ocenjevanje sproščanja nevarnih snovi - Določevanje
ostankov biocidov s tekočinsko kromatografijo in tandemsko masno
spektrometrijo (LC-MS/MS)

Construction products: Assessment of release of dangerous substances - Determination

of biocide residues using LC-MS/MS
Bauprodukte: Bewertung der Freisetzung von gefährlichen Stoffen - Bestimmung von
Biozid-Rückständen mittels LC-MS/MS
Produits de construction - Évaluation des émissions de substances dangereuses -
Détermination de la teneur en biocides par LC-MS/MS
Ta slovenski standard je istoveten z: prEN 17845
ICS:
13.020.99 Drugi standardi v zvezi z Other standards related to
varstvom okolja environmental protection
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
91.100.01 Gradbeni materiali na Construction materials in
splošno general
oSIST prEN 17845:2022 en,fr,de

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

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oSIST prEN 17845:2022
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oSIST prEN 17845:2022
DRAFT
EUROPEAN STANDARD
prEN 17845
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2022
ICS 91.100.01
English Version
Construction products: Assessment of release of
dangerous substances - Determination of biocide residues
using LC-MS/MS

Produits de construction - Évaluation des émissions de Bauprodukte: Bewertung der Freisetzung von

substances dangereuses - Détermination de la teneur gefährlichen Stoffen - Bestimmung von Biozid-

en biocides par LC-MS/MS Rückständen mittels LC-MS/MS

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 351.

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, 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.

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

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17845:2022 E

worldwide for CEN national Members.
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Contents Page

European foreword ............................................................................................................................................. 4

Introduction .......................................................................................................................................................... 5

1 Scope .......................................................................................................................................................... 6

2 Normative references .......................................................................................................................... 6

3 Terms and definitions ......................................................................................................................... 6

4 Abbreviations ......................................................................................................................................... 8

5 Principle ................................................................................................................................................... 9

6 Sample preparation .............................................................................................................................. 9

7 Reagents ................................................................................................................................................... 9

8 Apparatus and equipment ...............................................................................................................11

9 Procedure...............................................................................................................................................12

9.1 Preparation and storage of the samples .....................................................................................12

9.2 Preparation of eluates .......................................................................................................................12

9.3 Sample preparation for content analysis ...................................................................................12

9.4 Determination ......................................................................................................................................13

9.5 Test for interference and recovery ...............................................................................................13

10 Evaluation of results ..........................................................................................................................13

10.1 Identification ........................................................................................................................................13

10.2 Quantification .......................................................................................................................................13

10.3 Quality assurance ................................................................................................................................14

11 Calculation of results .........................................................................................................................15

11.1 Calculation of biocide concentrations without standard addition ...................................15

11.2 Calculation of biocide concentrations with standard addition ..........................................16

12 Precision .................................................................................................................................................18

13 Test report .............................................................................................................................................19

Annex A (normative) LC-UV method for content analysis .................................................................20

A.1 Extraction and clean-up ....................................................................................................................20

A.2 HPLC analysis ........................................................................................................................................20

A.3 Example of chromatographic conditions ....................................................................................20

A.4 Calibration .............................................................................................................................................21

A.4.1 General ....................................................................................................................................................21

A.4.2 Calibration curve .................................................................................................................................21

A.5 Calculation of biocide content in the construction product ................................................22

Annex B (informative) Solid phase extraction of eluates (example) .............................................23

Annex C (informative) Example conditions for suitable LC-MS/MS systems ..............................24

C.1 Example LC-MS/MS operating conditions ..................................................................................24

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C.2 HPLC system 1 ...................................................................................................................................... 24

C.3 HPLC-System 2 ..................................................................................................................................... 24

C.4 HPLC-System 3 ..................................................................................................................................... 25

C.5 HPLC-System 4 ..................................................................................................................................... 26

C.6 UHPLC system ...................................................................................................................................... 26

C.7 MS/MS system 1 .................................................................................................................................. 27

C.8 MS/MS system 2 .................................................................................................................................. 27

Annex D (informative) Precision data ...................................................................................................... 29

Bibliography ....................................................................................................................................................... 31

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European foreword

This document (prEN 17845:2022) has been prepared by Technical Committee CEN/TC 351

“Construction products - Assessment of release of dangerous substances”, the secretariat of which is held

by NEN.
This document is currently submitted to the CEN Enquiry.

This document has been prepared under a Standardization Request given to CEN by the European

Commission and the European Free Trade Association.
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Introduction

This document deals with the determination of the content of biocides in construction products and

eluates using liquid chromatography and tandem mass spectrometric detection (LC-MS/MS).

Following an extended evaluation of available methods for content and eluate analysis in construction

products (CEN/TR 16045 [1]) and subsequent method evaluation in the robustness validation [2] it was

concluded that eluate analysis and content analysis for biocides can be based on EN 15637 [3] after some

modifications.

This document is part of a modular horizontal approach and belongs to the analytical step. An overview

of all modules which belong to a chain of measurement and the manner how modules are selected is given

in CEN/TR 16220 [4].

In the growing amount of product and sector-oriented test methods it was recognized that many steps in

test procedures are or could be used in test procedures for many products, materials and sectors. It was

supposed that, by careful determination of these steps and selection of specific questions within these

steps, elements of the test procedure could be described in a way that can be used for all materials and

products or for all materials and products with certain specifications.

In this context a horizontal modular approach is adopted in CEN/TC 351. “Horizontal” means that the

methods can be used for a wide range of materials and products with certain properties. “Modular” means

that a test standard developed in this approach concerns a specific step in assessing a property and not

the whole “chain of measurement” (from sampling to analyses). A beneficial feature of this approach is

that “modules” can be replaced by better ones without jeopardizing the standard “chain”.

The use of modular horizontal standards implies the drawing of test schemes as well. Before executing a

test on a certain material or product to determine certain characteristics, it is necessary to draw up a

protocol in which the adequate modules are selected and together form the basis for the entire test

procedure.
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1 Scope

This document describes a method for the determination of the content of biocides in construction

products, (either finished (dried) or in a ready-to-use state) and in eluates thereof, using liquid

chromatography and tandem mass spectrometric detection (LC-MS/MS).

For content analysis liquid chromatography with UV-detection can also be used, if sufficient sensitivity

and selectivity is ensured (see Annex A).

The method in this document is validated for the product types listed in Annex D. For eluate analysis

quantification limits of 0,1 µg/l can be achieved.
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.

prEN 16637-2, Construction products: Assessment of release of dangerous substances — Part 2: Horizontal

dynamic surface leaching test

prEN 16637-3, Construction products: Assessment of release of dangerous substances — Part 3: Horizontal

up-flow percolation test

EN 16687:2015, Construction products — Assessment of release of dangerous substances — Terminology

EN 17087, Construction products: Assessment of release of dangerous substances — Preparation of test

portions from the laboratory sample for testing of release and analysis of content

3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 16687:2015 and the following

apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
blank value

test result obtained by carrying out the test procedure in the absence of a test portion

Note 1 to entry: The blank value is expressed in the same units as for presenting the test results as usual for that

test.
[SOURCE: EN 16687:2015, 4.1.10]
3.2
extract
solution resulting from extraction of a sample with a solvent
[SOURCE: CEN/TR 16045:2010, 2.2.4]
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3.3
extraction
dissolution of substances in a solvent for subsequent chemical analysis

Note 1 to entry: Extraction is usually done with an organic solvent to extract organic substances for chemical

analysis or for special analysis of inorganic substances.
[SOURCE: CEN/TR 16045:2010, 2.2.5]
3.4
laboratory sample
sample or subsample(s) sent to or received by the laboratory
[SOURCE: EN 16687:2015, 3.2.1]
3.5
method detection limit
MDL

smallest analyte concentration that can be detected with a specified analytical method including sample

preparation with a defined statistical probability

[SOURCE: EN ISO 17294-1:2006, 3.12, modified – “including sample preparation” added, symbol replaced

by abbreviation]
3.6
product matrix

main composition of the product dictating the manner of sample preparation and the type of digestion or

extraction for later chemical analysis

Note 1 to entry: For construction products for example the following product matrices can be distinguished:

— bituminous products;
— metals;
— plastics/rubbers;
— silica-based products;
— wood-based products.
[SOURCE: CEN/TR 16045:2010, 2.2.6; edited]
3.7
sample
portion of material selected from a larger quantity of material
[SOURCE: EN 16687:2015, 3.1.5]
3.8
test portion
analytical portion

amount of the test sample taken for testing/analysis purposes, usually of known weight or volume

[SOURCE: EN 16687:2015, 3.2.3]
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3.9
test sample

sample, prepared from the laboratory sample, from which test portions are removed for testing or

analysis
[SOURCE: EN 16687:2015, 3.2.2]
3.10
bitumen

very viscous liquid or solid, mainly consisting of hydrocarbons or their derivatives, that is virtually fully

soluble in carbon disulphide
3.11
asphalt
natural or artificial mixture of bitumen and mineral materials
3.12
Soxhlet extraction

chemical pre-treatment of a solid subsample, where the organic compounds to be determined are

dissolved by the Soxhlet technique
3.13
final extract

solution that is obtained after reprocessing the Soxhlet extract through a purification stage

3.14
external standard

known quantity of the target analytes that is measured in the same series as the solution to be measured

and is used for identification and quantification
3.15
internal standard

known quantity of a substance (where applicable deuterated) not present in the sample, which is added

to the analysis sample in order to determine the recovery
4 Abbreviations
For the purposes of this document, the following abbreviations apply.
EOTA European Organisation of Technical Assessment
LC Liquid chromatography
MS Mass spectrometry;
Mass selective detection
TR Technical Report (ISO, CEN or EOTA)
TS Technical Specification (ISO, CEN or EOTA)
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5 Principle

Quantification of biocides is performed by liquid chromatography with tandem mass spectrometric

detection (LC-MS/MS), using electrospray ionization. Eluates are injected directly into the LC-MS system.

Solid and pasty samples are extracted with methanol or a methanol/water mixture. Clean up may be

applied when necessary by solid phase supported liquid-liquid extraction.

To achieve the required selectivity the mass spectrometer is operated in the multiple reaction monitoring

mode (MRM).
6 Sample preparation

To obtain test samples for extraction (and analysis) guidance on sample preparation as specified in

EN 17087 shall be applied.

Precautions shall be taken before and during transport of the laboratory sample as well as during the

time in which the samples are preserved in the laboratory before being analysed, to avoid alteration of

the sample (see CEN/TR 16220).

Extracts are susceptible to change due to physical or chemical reactions which can take place between

the time of extraction and the analysis.

It is therefore essential to take the necessary precautions to minimize these reactions and in the case of

many parameters to analyse the extract with a minimum of delay. The maximum delay is given in the

respective analytical standards.
7 Reagents

Use reagents of recognized analytical grade, unless otherwise specified. Take every precaution to avoid

possible contamination of water, solvents, inorganic salts, etc.

7.1 Additive for LC-eluent depending on method used, e.g. ammonium formate, formic acid, acetic

acid.
7.2 Water, HPLC quality.
7.3 Dichloromethane, for biocide analysis.
7.4 Methanol, HPLC quality.

7.5 Internal Standard (ISTD) solutions in methanol, mass concentration ρ = 10 µg/ml to 50 µg/ml .

Use as much as possible isotope labelled internal standards, if available and obtainable at reasonable

price. The internal standard solution should be added at the extraction step and to standard solutions.

7.6 Biocide stock solutions.

Prepare individual stock solutions of analytical standards at concentrations that are sufficiently high to

allow the preparation of complex biocide mixtures. The solvent used shall not negatively influence the

stability of the biocides employed.

Usually, store stock solutions at ~ −18 °C. Check the stability of stock solutions during storage regularly.

In some cases, the addition of acids or bases is helpful to enhance stability and extend the acceptable

storage period.
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7.7 Biocide mixtures.

Because of the broad applicability of this method and due to the partly divergent pH-stability of biocides,

analyte mixtures of different composition might be needed. These are prepared by mixing together

defined volumes of the required biocide stock solutions (7.6) and appropriately diluting them with

methanol. The analyte concentrations in this mixture should be sufficient to allow the preparation of the

required matrix matched standards (see 7.8.3) with moderate dilution of the blank sample extract (e.g.

less than 20 %).

Usually, biocide mixtures are stored at approximately −18 °C. Since the stability of the biocides in the

mixture can be lower than in stock solutions, stability has to be checked regularly. In some cases, the

addition of acids or bases is helpful to enhance stability and extend acceptable storage times.

7.8 Standard solutions.
7.8.1 Standard solutions prepared in pure solvent (solvent-based standards).

Solvent-based standards are prepared by mixing a certain volume of methanol with known amounts of

biocide mixtures (7.7). The preparation of multiple standards of different biocide concentration is useful

to cover a broad concentration range.

NOTE The linear range of calibration depends on the sensitivity of the instrument and the MS signal response

of the biocide. A calibration range of 0,1 µg/l to 100 µg/l correlates to a biocide content of 0,3 mg/kg to 300 mg/kg

when a 10 g sample is employed (see 9.3.1).
7.8.2 Standard solutions with internal standard prepared in pure solvent.

Solvent-based standards with ISTD are prepared by mixing a certain volume of methanol with known

amounts of biocide mixtures (7.7) and a fixed volume of internal standard solution (7.5).

The volume used shall result in that concentration of ISTD which is obtained in the final extracts after

sample extraction and clean-up (see 9.2 and 9.3). The concentration of internal standard in the final

sample

extract ( c ) is calculated using Formula (1). The preparation of multiple standards of different

ISTD

biocide concentration but with constant ISTD concentration is useful to cover a broad concentration

range.
Vc×× V
sample
ISTD ISTD 1
c = (1)
ISTD
VV×
ex end
where
sample is the concentration of internal standard in the final extract, in µg/ml;
ISTD

V is the volume of internal standard solution (7.5) added to the test portion, in ml;

ISTD
c is the concentration of internal standard solution (7.5), in µg/ml;
ISTD

V is the volume used for solid supported liquid/liquid extraction, in ml (here: 5 ml);

V is the total volume of extraction solvents, in ml (here: 30 ml);
V is the final volume of extract obtained after clean-up, in ml (here: 0,5 ml).
end
In case no clean-up is applied Formula (1) simplifies to:
Vc×
sample ISTD ISTD
c = (1')
ISTD
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7.8.3 Standard solutions prepared in blank matrix extracts (matrix-matched standards).

Prepare matrix-matched standards in the same way as the solvent-based standards, however, instead of

pure methanol use extracts of blank samples (prepared as described in 9.2, but without ISTD addition).

To minimize errors caused by matrix induced effects during chromatography, it is best to choose similar

commodities (e.g. sealant for sealant samples, render for render samples, wood for treated wood samples,

insulation foam for insulation foam samples, etc.).

The stability of biocide in matrix-matched standards can be lower than that of standards in pure

acetonitrile and has to be checked more thoroughly.

7.9 Cartridge for solid supported liquid/liquid extraction of appropriate sample volume (e.g. 5 ml

or 20 ml), diatomaceous earth, for example ChemElut CE 1005 .
7.10 Solid phase extraction (SPE) cartridges, e.g. OASIS HLB 6 ml, 200 mg .
8 Apparatus and equipment
Usual laboratory apparatus and, in particular, the following:
8.1 Suitable equipment for sample comminution and grinding.
8.2 Laboratory balance, accuracy: 0,01 g.
8.3 Volumetric flasks, 10 ml and 20 ml.
8.4 Ultrasonic bath.
8.5 Centrifuge tubes, suitable to withstand acceleration.

8.6 Centrifuge, capable of producing a relative centrifugal force (RCF) of at least 3000 g (at the bottom

of the tube).
8.7 Round bottom flasks, capacity 50 ml and 250 ml.
8.8 Glass syringe, minimum volume 2 ml.
8.9 Microlitre syringes, for sample fortification.
8.10 Rotary evaporator, with temperature-controlled water bath.

8.11 Syringe filters, 0,45 µm pore size, polytetrafluoroethylene (PTFE) membrane.

8.12 Glass vials and caps, 1,8 ml volume, suitable for an autosampler.

8.13 LC-MS/MS system, triple quadrupole mass spectrometer with electrospray interface.

NOTE Depending on construction product, matrix, system interferences, biocide and LOQ-requirement, it is

possible that reliable results are to be obtained using a less selective detection system, e.g. LC/UV.

8.14 SPE equipment, e.g. vacuum manifold.

ChemElut and OASIS HLB are trade names of products. This information is given for the convenience of users of

this European Standard and does not constitute an endorsement by CEN of the product named. Equivalent products

may be used if they can be shown to lead to the same results.
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9 Procedure
9.1 Preparation and storage of the samples

Sample processing and storage procedures should be demonstrated to have no significant effect on the

biocides present in the test sample. Processing should also ensure that the test sample is homogeneous

enough so that sub-sampling variability is acceptable. If a single analytical portion is unlikely to be

representative of the test sample, larger or replicate portions shall be analysed, to provide a better

estimate of the true value. For content analysis, the degree of comminution of solid samples supports

a quantitative biocide extraction.
9.2 Preparation of eluates

Make eluates according to EN 16637-2 and EN 16637-3; centrifuge the eluates, take a test portion, add

internal standard and proceed to 9.4.

Depending on the sensitivity of the instrument and the required limit of quantification it can be necessary

to concentrate the eluates by solid phase extraction (SPE). An example of an SPE procedure is given in

Annex B.
9.3 Sample preparation for content analysis
9.3.1 Extraction

The reduction of the sample shall be carried out in such a way that representative portions are obtained

(see EN 17087). Follow guidance in this standard for any other aspects of sample pre-treatment. This

results in the test sample. Calculation of the biocide shall be based on the mass of the original test sample.

For dry sample materials weigh a homogenized portion of 5 g (m ) into the centrifuge tube (8.5). Add

10 ml of water and 20 ml of methanol (7.4). Homogenize for approximately 2 min (e.g. using a high-speed

blender). Take at least 10 ml of the resulting extract of 30 ml (= V ) and centrifuge at a minimum of

3 000 g for at least 10 min.

For pasty products, transfer a representative test portion of m = 10 g into a centrifuge tube (8.5). Add

10 ml of water and 20 ml of methanol (7.4). Homogenize for approximately 2 min (e.g. using a high-speed

blender). Take at least 10 ml of the resulting extract (V ) and centrifuge at a minimum of 3 000 g for at

least 10 min. If the product is partly or completely dissolved in the extraction solvent, the volume V has

to be corrected, taken the sample volume into account.

As an option an internal standard may be used additionally. In that case add a small volume (<1 % of V )

of internal standard solution (= V ) to the test portion after addition of 20 ml of methanol.

ISTD
9.3.2 Clean-up

If necessary, apply 5 ml of the diluted centrifugate (= V ) from 9.3.2 to a 5 ml cartridge (7.9). After

approximately 5 minutes, elute into a 50 ml round bottom flask (8.7), using 12,5 ml of dichloromethane

(7.3). Repeat the elution with another 12,5 ml of dichloromethane. Reduce the combined eluates almost

to dryness using the rotary evaporator (8.10). Remaining dichloromethane shall be removed with

a gentle stream of nitrogen. Add 500 µl of methanol (7.4) to the round bottom flask and weigh with

stopper. Carefully dissolve the biocide by swirling the flask in the ultrasonic bath (8.4), but avoid losses

of methanol. If losses of methanol occur (re-weighing), add methanol to obtain the previous total weight.

Filter the obtained sample test solution of 0,5 ml (= V ) through a PTFE-filter (8.11) into a sample vial

end
(8.12) for injection.
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