kSIST FprEN ISO 11916-3:2021

Soil quality - Determination of selected explosives and related compounds - Part 3: Method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) (ISO/FDIS 11916-3:2021)

8. Scope
Scope of the proposed deliverable.
This International Standard specifies the measurement of explosive and related nitrocompounds
compounds using liquid chromatography–tandem mass spectrometry (LC-MS/MS) in soil and soilmaterials. This method is applicable to 12 compounds (1,3-DNB, 1,3,5-TNB, 2,4-DNT, 2,6-DNT, 2,4,6-TNT, 4-A-2,6-DNT, 2-A-4,6-DNT, Tetryl, Hexyl, RDX, HMX, PETN) listed in ISO 11916-1(soil, HPLC/UV method) except nitrobenzene, 2-nitortoluene, 3-nitrotoluene and 4-nitrotoluene. In particular,this method is effective for the analysis of PETN, 1,3,5-TNB and tetryl which showed poor interlaboratory trial results with ISO 11916-1. Under the conditions specified in this document, concentrations as low as 0,005 mg/kg to 0,014 mg/kg-dry matter can be determined, depending on the substance.
Purpose and justification of the proposal*
Currently two ISO standards exist for the analysis of explosives and related compounds in soil: ISO 11916-1(HPLC/UV method), ISO 11916-2(GC-ECD or MS method). According to the results of interlaboratory trial with ISO 11916-1, it showed some problematic aspects to analyze PETN, 1,3,5-TNB and tetryl. In case of ISO 11916-2, it also gave poor inter-laboratory trial results for 1,3,5-TNB. Therefore, it is necessary to develop new method effectively applicable to the determination of PETN, 1,3,5-TNB and tetryl.
In addition to this, lower risk-based PRGs (Preliminary Remediation Goal), new regulatory concerns, and change of land use have created the atmosphere to apply more sensitive and selective instruments to determine explosive and related compounds. From the view of these aspects, liquid chromatography–tandem mass spectrometry (LC-MS/MS) is one of alternative methods for these purposes. LC-MS/MS method provides 10-20 times or much lower detection limit than that of HPLC/UV method and is recommendable to determine PETN, 1,3,5-TNB and tetryl.
Also LC-MS/MS method is getting more familiar in ISO standard development (e.g. ISO/CD22104 Water quality--Microcystins, ISO/NP21677 Water quality--HBCD, ISO/CD21675 Water quality--PFAS).
Consider the following: Is there a verified market need for the proposal? What problem does this
standard solve? What value will the document bring to end-users? See Annex C of the ISO/IEC
Directives part 1 for more information. See the following guidance on justification statements on ISO Connect:
https://connect.iso.org/pages/viewpage.action?pageId=27590861

Bodenbeschaffenheit - Bestimmung von ausgewählten Explosivstoffen und verwandten Verbindungen - Teil 3: Verfahren mittels Flüssigkeitschromatographie mit Tandem-Massenspektrometrie (LC-MS/MS) (ISO/FDIS 11916-3:2021)

Dieses Dokument legt ein Verfahren zur Messung von Explosivstoffen und verwandten Nitroverbindungen (wie in Tabelle 1 angegeben) in Böden und Bodenmaterialien fest. Dieses Dokument ist für die Spurenanalyse von Explosivstoffen und verwandten Verbindungen mittels Flüssigkeitschromatographie mit Tandem Massenspektrometrie (LC MS/MS) vorgesehen. Im Allgemeinen zeigt die LC MS/MS Messung für jede Verbindung in Tabelle 1 die niedrigere Bestimmungsgrenze (LOQ) (en: limit of quantification) als bei der Verwendung von Hochleistungs Flüssigkeitschromatographie (HPLC) mit UV-Detektion.
Unter den in diesem Dokument festgelegten Bedingungen können in Abhängigkeit von der jeweiligen Substanz Konzentrationen von 0,005 mg/kg bis 0,014 mg/kg, bezogen auf die Trockenmasse, bestimmt werden. Ähnliche Verbindungen, insbesondere verschiedene Nitroaromate, Nebenprodukte und Abbaupro¬dukte von Explosivstoffen, dürfen nach diesem Verfahren analysiert werden. Die Anwendbarkeit sollte jedoch im Einzelfall geprüft werden.
[Tabelle 1]

Qualité du sol - Dosage d'une sélection d'explosifs et de composés apparentés - Partie 3: Méthode utilisant la chromatographie en phase liquide couplée à la spectrométrie de masse en tandem (CL-SM/SM) (ISO/FDIS 11916-3:2021)

Kakovost tal - Določevanje izbranih eksplozivov in podobnih spojin - 3. del: Metoda s tekočinsko kromatografijo s tandemsko masno spektrometrijo (LC-MS/MS) (ISOFDIS 11916-3:2021)

General Information

• Status: Not Published
• Public Enquiry End Date: 03-May-2020
• ICS: 13.080.10 - Chemical characteristics of soils
• Technical Committee: KAT - Soil quality
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 18-Jun-2021
• Due Date: 06-Aug-2021
• Completion Date: 02-Aug-2021
• Ref Project: EN ISO 11916-3:2021 - Soil quality - Determination of selected explosives and related compounds - Part 3: Method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) (ISO 11916-3:2021)

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN ISO 11916-3:2020
01-april-2020
[Not translated]

Soil quality - Determination of selected explosives and related compounds - Part 3:

Method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) (ISO/DIS
11916-3:2020)
Bodenbeschaffenheit - Bestimmung von ausgewählten Explosivstoffen und verwandten
Verbindungen - Teil 3: Verfahren mittels Flüssigkeitschromatographie mit Tandem-
Massenspektrometrie (LC-MS/MS) (ISO/DIS 11916-3:2020)

Qualité du sol - Dosage d'une sélection d'explosifs et de composés apparentés - Partie

3: Méthode utilisant la chromatographie en phase liquide couplée à la spectrométrie de

masse en tandem (CL-SM/SM) (ISO/DIS 11916-3:2020)
Ta slovenski standard je istoveten z: prEN ISO 11916-3
ICS:
13.080.10 Kemijske značilnosti tal Chemical characteristics of
soils
oSIST prEN ISO 11916-3:2020 en,fr,de

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

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oSIST prEN ISO 11916-3:2020
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oSIST prEN ISO 11916-3:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 11916-3
ISO/TC 190/SC 3 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-02-18 2020-05-12
Soil quality — Determination of selected explosives and
related compounds —
Part 3:
Method using liquid chromatography-tandem mass
spectrometry (LC-MS/MS)
ICS: 13.080.10
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 11916-3:2020(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 2020
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oSIST prEN ISO 11916-3:2020
ISO/DIS 11916-3:2020(E)
COPYRIGHT PROTECTED DOCUMENT
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oSIST prEN ISO 11916-3:2020
ISO/DIS 11916-3:2020(E)

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This document was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 3,

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Permission can be requested from either ISO at the address below or ISO’s member body in the

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oSIST prEN ISO 11916-3:2020
ISO/DIS 11916-3:2020(E)
Contents Page

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

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

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

3 Principle ..............................................................................................................................................................2

4 Interferences .....................................................................................................................................................2

5 Reagents ..............................................................................................................................................................2

5.1 General ................................................................................................................................................................2

5.2 Chemicals ............................................................................................................................................................3

5.2.1 Water, with a electrical conductivity of ≥ 0.01 mS/m (25°C). ..........................................................3

5.2.2 Acetonitrile, CH3CN, HPLC grade or equivalent. ...................................................................................3

5.2.3 Methanol, CH3OH, HPLC grade or equivalent. ........................................................................................3

5.2.4 Ammonium acetate in water, 2,5 mmol/l. ...............................................................................................3

5.2.5 Ammonium acetate in methanol, 2,5 mmol/l. .......................................................................................3

5.3 Standard substances and solutions ...........................................................................................................3

5.3.1 Standard substances .......................................................................................................................................3

5.3.2 Standard solutions ..........................................................................................................................................3

6 Apparatus ...........................................................................................................................................................4

6.1 General ................................................................................................................................................................4

6.1.1 Amber glass containers with caps containing PTFE coated lining. ................................................4

6.1.2 Amber glass vials with caps containing septa with PTFE coated lining. ......................................4

6.1.3 Amber glass conical bottles with ground-in stopper. .........................................................................4

6.1.4 Analytical balance, with a precision of at least 0,1 mg. ......................................................................4

6.1.5 Laboratory centrifuge, capable of producing an acceleration of at least 1 000 G. ...................4

6.1.6 Membrane filter, 0,45 µm pore size. .........................................................................................................4

6.2 Equipment for extraction..............................................................................................................................4

6.2.1 Temperature-controlled ultrasonic bath, 35 Hz, effective HF-power of at least 140 W. .......4

6.2.2 Horizontal mechanical shaker. ...................................................................................................................4

6.3 Liquid chromatograph-tandem mass spectrometer (LC-MS/MS) ..................................................5

6.3.1 LC system, consisting of a pump that supports a pressure of at least 40 MPa (400

bar) and an injection system with an appropriate loop capacity depending on

injection volume. .............................................................................................................................................5

6.3.2 Tandem mass spectrometer ........................................................................................................................5

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

7.1 Sample pretreatment, sample storage and determination of water content ............................5

7.2 Extraction ...........................................................................................................................................................5

7.2.1 General ................................................................................................................................................................5

7.2.2 Extraction using ultrasonic waves .............................................................................................................6

7.2.3 Extraction using mechanical shaking .......................................................................................................6

7.3 Storage of extract .............................................................................................................................................6

8 Liquid chromatography tandem mass spectrometry (LC-MS/MS) ................................................7

8.1 General ................................................................................................................................................................7

8.2 Identification and quantification ...............................................................................................................7

8.3 Calibration ..........................................................................................................................................................7

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9 Calculation of results ..................................................................................................................................... 8

10 Quality assurance/quality control (QA/QC) .......................................................................................... 8

11 Expression of results ...................................................................................................................................... 9

12 Test report ......................................................................................................................................................... 9

Annex A (informative) Conditions of high performance liquid chromatography tandem

mass spectrometry (LC-MS/MS) ............................................................................................................. 11

Annex B (informative) Comparison of LC-MS and LC-MS/MS application for PETN, 1,3,5-TNB

and tetryl ......................................................................................................................................................... 14

B.1 Descriptions of experiment ...................................................................................................................... 14

B.2 Ion chromatogram of LC-MS (SIM) and LC-MS/MS (MRM) ............................................................ 14

Annex C (informative) Comparison of LOD and LOQ in the measurement of HPLC and LC-

MS/MS............................................................................................................................................................... 17

C.1 Analytical conditions of HPLC ................................................................................................................. 17

Annex D (informative) Comparison of extractive capability of acetonitrile and methanol

when using LC-MS/MS ................................................................................................................................ 20

D.1 Descriptions of experiment ....................................................................................................................... 20

D.2 Results .............................................................................................................................................................. 20

Bibliography ................................................................................................................................................................. 22

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Introduction

Currently two ISO standards exist for the analysis of explosives and related compounds in soil: ISO

11916-1(HPLC/UV method), ISO 11916-2(GC-ECD or MS). According to the results of inter-laboratory

trial with ISO 11916-1, it showed some problematic aspects to analyze PETN, 1,3,5-TNB and tetryl. In

case of ISO 11916-2, it also gave poor inter-laboratory trial results for 1,3,5-TNB. Therefore, it is

necessary to develop new method effectively applicable to the determination of PETN, 1,3,5-TNB and

tetryl. In addition to this, lower risk-based PRGs (Preliminary Remediation Goal), new regulatory

concerns, and change of land use have created the atmosphere to apply more sensitive and selective

instruments to determine explosive and related compounds. From the view of these aspects, liquid

chromatography–tandem mass spectrometry (LC-MS/MS) is one of alternative methods for these

purposes. LC-MS/MS method provides 10-20 times or more lower detection limit than that of HPLC/UV

method. In this document, LC-MS/MS method is intended for the trace analysis of explosives and related

compounds and applicable to 12 compounds (1,3-DNB, 1,3,5-TNB, 2,4-DNT, 2,6-DNT, 2,4,6-TNT, 4-A-

2,6-DNT, 2-A-4,6-DNT, Tetryl, Hexyl, RDX, HMX, PETN) listed in ISO 11916-1(soil, HPLC/UV method)

except for nitrobenzene, 2-nitrotoluene, 3-nitrotoluene and 4-nitrotoluene. In case of nitrobenzene and

nitrotoluenes, they have the low sensitivity in LC-MS/MS measurement. In particular, this method is

effective for the analysis of PETN, 1,3,5-TNB and tetryl when comparing with the method using HPLC.

Also LC-MS/MS method is getting more familiar in ISO standard development (e.g. ISO/CD22104 Water

quality--Microcystins, ISO/NP21677 Water quality--HBCD, ISO/CD21675 Water quality--PFAS).

© ISO 2020 – All rights reserved
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oSIST prEN ISO 11916-3:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 11916-3:2020(E)
Soil quality — Determination of selected explosives and
related compounds — — Part 3: Method using liquid
chromatography-tandem mass spectrometry (LC-MS/MS)
1 Scope

This part of ISO 11916 specifies the measurement of explosives and related nitrocompounds (as given

in Table 1) in soil and soil materials. This document is intended for the trace analysis of explosives and

related compounds by liquid chromatography–tandem mass spectrometry (LC-MS/MS). Generally, LC-

MS/MS measurement shows the lower LOQ (limit of quantification) for each compound in Table 1

than that of high-performance liquid chromatography (HPLC) measurement.

Under the conditions specified in this document, concentrations as low as 0,005 mg/kg to 0,014 mg/kg-

dry matter can be determined, depending on the substance. Similar compounds, in particular various

nitroaromatics, by-products and degradation products of explosive compounds may be analyzed using

this method. However, the applicability should be checked on a case-by-case basis.

Table 1 — Explosive and related nitrocompounds for analysis
Compound Abbreviation CAS-RN
1,3-Dinitrobenzene 1,3-DNB 99-65-0
1,3,5-Trinitrobenzene 1,3,5-TNB 99-35-4
2,4-Dinitrotoluene 2,4-DNT 121-14-2
2,6-Dinitrotoluene 2,6-DNT 606-20-2
2,4,6-Trinitrotoluene 2,4,6-TNT 118-96-7
4-Amino-2,6-dinitrotoluene 4-A-2,6-DNT 19406-51-6
2-Amino-4,6-dinitrotoluene 2-A-4,6-DNT 35572-78-2
N-Methyl-N-2,4,6-tetranitroaniline Tetryl 479-45-8
2,4,6-Trinitro-N-(2,4,6-trinitrophenyl)aniline Hexyl 131-73-7
1,3,5-Trinitrohexahydro-1,3,5-triazine RDX 121-82-4
1,3,5,7-Tetranitroo ctahydro-1,3,5,7-tetrazocine HMX 2691-41-0
Pentaerythrityltetranitrate PETN 78-11-5
CAS-RN: Chemical Abstract Service-Registry Number
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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 11465, Soil quality — Determination of dry matter and water content on a mass basis —

Gravimetric method
3 Principle

Explosive materials in soils are extracted with acetonitrile by using one of the following techniques:

— ultrasonic bath with ultrasonic waves as medium (USE);
— horizontal mechanical shaker at room temperature (MSE);

There are two further extraction procedures such as pressurized liquid extraction (PLE) and soxhlet

apparatus that works isothermically at boiling temperature (SOX). However, they might not be suitable

for PETN, tetryl and 1,3,5-TNB.

The extract containing the analytes is either injected directly, or if necessary diluted prior to injection,

into a reversed-phase high-performance liquid chromatograph–tandem mass spectrometer (LC-

MS/MS).

WARNING — Take care when transporting, storing or treating explosive materials. High

temperature, high pressure and static electricity shall be prevented when storing explosive

materials. Small amounts of explosive materials should be kept moist in a cool, dark place. Soil

samples containing explosives with a mass fraction of less than 1 % do not have a risk of

explosion.
4 Interferences

Solvents, reagents, glassware, and other hardware used for sample processing may yield artifacts

and/or elevated baselines, causing misinterpretation of the chromatograms. All of these materials shall

therefore be demonstrated to be free of contaminants and interferences through the analysis of method

blanks.

Samples containing 2,4,6-trinitrobenzoic acid should not be extracted with acetonitrile as it may result

in the overestimation of 1,3,5-TNB due to decarboxylation. To avoid this interference, methanol

extraction can be an alternative method for 1,3,5-TNB.
5 Reagents
5.1 General
All reagents shall be blank-free and of recognized analytical grade.
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5.2 Chemicals
5.2.1 Water, with a electrical conductivity of ≥ 0.01 mS/m (25°C).
5.2.2 Acetonitrile, CH3CN, HPLC grade or equivalent.
5.2.3 Methanol, CH3OH, HPLC grade or equivalent.
5.2.4 Ammonium acetate in water, 2,5 mmol/l.

For the preparation, weigh 96,3 mg of ammonium acetate(C H NO ) into 500 ml measuring flasks

2 7 2

(scale: mg/ml), fill up to the mark with water (5.2.1). Prepare the reagent just before it is used. Before

using as a mobile phase, filter the reagent using filter paper (6.1.7). After filtration, degas the filtrate

using sonic bath or other methods.
5.2.5 Ammonium acetate in methanol, 2,5 mmol/l.

For the preparation, weigh 96,3 mg of ammonium acetate(C2H7NO2) into 500 ml measuring flasks

(scale: mg/ml), fill up to the mark with methanol (5.2.3). Prepare the reagent just before it is used.

Before using as a mobile phase, filter the reagent using filter paper (6.1.7). After filtration, degas the

filtrate using sonic bath or other methods.
5.3 Standard substances and solutions
5.3.1 Standard substances
5.3.1.1 Reference substances
Compounds listed in Table 1.
5.3.1.2 Method-checking standards

Suitable compound(s) not found in the sample (i.e. 2,5-dinitrotoluene or 1,2-dinitrobenzene). It is

recommended that the concentration of method-checking standards in the final extract is ranged from

0,04 mg/l to 0,1 mg/l. Before selecting the method-checking standards, confirm the applicability of

those standards according to the analytical conditions of each laboratory.
5.3.2 Standard solutions
5.3.2.1 General
All standard solutions used in this method shall be prepared as described below.

NOTE If commercially available certified standard stock solutions are used, calibration solutions are

prepared in volumetric flasks by diluting the stock solutions with acetonitrile (5.2.2).

All dilution steps shall not exceed the factor 100.
5.3.2.2 Single-substance stock solutions

For the preparation, weigh 50 mg ± 0,1 mg of the reference substances into 50 ml measuring flasks

(scale: mg/ml), fill up to the mark with acetonitrile (5.2.2) and let the reference substances dissolve

completely.
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oSIST prEN ISO 11916-3:2020
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Transfer the stock solutions to amber-glass flasks and seal with polytetrafluoroethylene (PTFE)-coated

screw caps. The stock solutions can be kept in the refrigerator at 2 °C to 6 °C in the dark for up to 6

month.
5.3.2.3 Multi-component stock solutions

Prepare multi-component stock solutions of different concentrations from the various single-substance

stock solutions (5.3.2.2) by mixing and diluting with acetonitrile (5.2.2).At concentrations below 1

mg/ml, solutions should be checked after one week as reference substances may decompose.

5.3.2.4 Calibration standard solutions

Calibration standard solutions are prepared by the dilution of multi-component stock solutions. The

working range of 0,01 mg/l to 0,2 mg/l is recommendable. A minimum of 5 concentration levels is

needed for the calibration.
6 Apparatus
6.1 General
Usual laboratory apparatus and the followings.
6.1.1 Amber glass containers with caps containing PTFE coated lining.
6.1.2 Amber glass vials with caps containing septa with PTFE coated lining.
6.1.3 Amber glass conical bottles with ground-in stopper.
6.1.4 Analytical balance, with a precision of at least 0,1 mg.

6.1.5 Laboratory centrifuge, capable of producing an acceleration of at least 1 000 G.

6.1.6 Membrane filter, 0,45 µm pore size.

Any adsorption of the target compounds shall be avoided. No interfering material shall be eluated.

PTFE, polyamide or an equivalent material is recommended.
6.2 Equipment for extraction

6.2.1 Temperature-controlled ultrasonic bath, 35 Hz, effective HF-power of at least 140 W.

Water bath capable of maintaining the temperature at (30 ± 5) °C or at (50 ± 5) °C during ultrasonic

extraction.
6.2.2 Horizontal mechanical shaker.

The shaker shall maintain a frequency of 100 cycles/min and offer a shaking width of about 10 cm.

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6.3 Liquid chromatograph-tandem mass spectrometer (LC-MS/MS)

6.3.1 LC system, consisting of a pump that supports a pressure of at least 40 MPa (400 bar) and an

injection system with an appropriate loop capacity depending on injection volume.

6.3.1.1 Stationary phase

Temperature-controlled columns packed with reversed phasematerial. The column should be selected

from those made by filling 25 cm long stainless tubes with inner diameters within the range of 2,1mm

to 4,6 mm with silica gel (particle diameter 5 m) chemically bonded with octadecylsilyl (ODS) group or

those with an equivalent separating ability. If the applicability is verified, other types of column can be

used.

NOTE For verification purposes, where applicable, repeat the chromatographic separation using a

column of different selectivity; CN reversed-phase column or phenyl-hexyl reversed-phase column are

recommended.
6.3.1.2 Mobile phase

A solution made by mixing 2,5 mmol/l ammonium acetate in water (5.2.4) with 2,5 mmol/l ammonium

acetate in methanol (5.2.5) can be used as a mobile phase.
6.3.2 Tandem mass spectrometer

The LC-MS/MS system should be capable of negative ion atmospheric pressure chemical Ionization

(APCI). Use a triple quadrupole tandem mass analyzer (MS/MS) consisting of two successive

quadrupole mass analyzer or a system with at least equivalent performance as a mass spectrometer.

Also, multiple reaction monitoring (MRM) mode should be available for mass analysis.

7 Procedure
7.1 Sample pretreatment, sample storage and determination of water content

While taking a field-moist sample, remove coarse impurities, e.g. plant residues and stones. Put the

sample in an amber glass flask and store immediately in a cool, dark transport container.

Soil samples shall be analyzed as soon as possible. Before analyzing the sample, homogenize the sample

through a sieve with an aperture of 2 mm.

Soil samples shall be stored in a dark place at (4 ± 2) °C. Samples thatare stored for longer periods (i.e. >

than 1 week) prior to analysis, shall be stored at −20 °C.

In order to calculate the dry matter based content of explosive compounds, determine the dry matter

content of the field-moist soil in accordance with ISO 11465. Be aware of potential evaporation of

volatile toxic contaminants.
7.2 Extraction
7.2.1 General
For extraction, the following two methods may be applied:
— extraction using ultrasonic waves;
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oSIST prEN ISO 11916-3:2020
ISO/DIS 11916-3:2020(E)
— extraction using mechanical shaking.

The use of a method-checking standard is recommended. Method-checking standards have to be added

prior to extraction. For the selection of suitable method-checking standards, refer to 5.3.1.2. When

comparing with acetonitrile, methanol has showed serious problem in the recovery test for HMX, RDX

and tetryl with LC-MS/MS detection (refer to Annex D). Also, it should be avoided to extract tetryl at the

temperatures above room temperature.
7.2.2 Extraction using ultrasonic waves

Take approximately 20 g of the field-moist sample and weighit into the extraction container (6.1.1) with

a precision of ± 0,1 g and add the method-checking standard (5.3.1.2), if used, with a concentration

range of 0,04 mg/l to 0,1 mg/l in the final extract. Add 40 ml ± 0,1 ml of acetonitrile (5.2.2) and seal

with a cap containing a PTFE coated lining. Shake the vial briefly by hand, and then apply ultrasonic

extraction in the bath (6.2.1) for 16 h at (30 ± 5) °C or 4 h at (50 ± 5) °C. During extraction, the water

level in the bath should be at least 1 cm above the level of the solvent inside the extraction flasks. This

extraction method might not be proper for tetryl.

After applying ultrasonic extraction, allow the soil particles to settle for 30 min. Do not open the vial

before it has cooled down to room temperature. If necessary, filter an aliquot of the supernatant using a

0,45 µm PTFE or polyamide filter (6.1.7) into the vial (6.1.2) or centrifuge at 1 000 G for 20 min.

It is recommended to li
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