United States 

Environmental Protection

Agency 

Office of Research and 

Development 

Washington, DC 20460

EPA/600/R-07/004 

 January 2007 

A Literature Review of Wipe 

Sampling Methods for 

Chemical Warfare Agents and 

Toxic Industrial Chemicals 

EPA/600/R-07/004 

 January 2007 

A Literature Review of Wipe 

ampling Methods for Chemical 

Warfare Agents and Toxic 

Industrial Chemicals 

S

Prepared by 

Battelle 

505 King Avenue 

Columbus, Ohio 43201 

Contract No. GS23F0011L-3 

Task Order No. 1125 

Stephen Billets 

Environmental Sciences Division 

National Exposure Research Laboratory 

Office of Research and Development 

U.S. Environmental Protection Agency 

Las Vegas, NV 89119 
ii

Notice

This document was prepared for the U.S. Environmental Protection Agency (EPA) under 

Contract No. GS23F0011L-3, Task Order No. 1125. The document has met the EPA’s 

requirements for peer and administrative review and has been approved for publication. Mention 

of corporation names, trade names, or commercial products does not constitute endorsement or 

recommendation for use. 
iii

Abstract 

Wipe sampling is an important technique for the estimation of contaminant deposition in 

buildings, homes, or outdoor surfaces as a source of possible human exposure. Numerous 

methods of wipe sampling exist, and each method has its own specification for the type of wipe, 

wetting solvent, and determinative step to be used, depending upon the contaminant of concern. 

The objective of this report is to concisely summarize the findings of a literature review that was 

conducted to identify the state-of-the-art wipe sampling techniques for a target list of 

compounds. This report describes the methods used to perform the literature review; a brief 

review of wipe sampling techniques in general; an analysis of physical and chemical properties 

of each target analyte; an analysis of wipe sampling techniques for the target analyte list; and a 

summary of the wipe sampling techniques for the target analyte list, including existing data gaps. 

In general, no overwhelming consensus can be drawn from the current literature on how to 

collect a wipe sample for the chemical warfare agents, organophosphate pesticides, and other 

toxic industrial chemicals of interest to this study. Different methods, media, and wetting 

solvents have been recommended and used by various groups and different studies. For many of 

the compounds of interest, no specific wipe sampling methodology has been established for their 

collection. Before a wipe sampling method (or methods) can be established for the compounds 

discussed in this report, two steps must be taken: (1) conduct investigative research to fill in the 

gaps in wipe sampling knowledge, and (2) conduct method validation to optimize the methods. 
iv
Table of Contents 

Chapter 1 Introduction ................................................................................................................... 1 

Chapter 2 Literature Search Methods ............................................................................................ 3 

2.1 Literature Review................................................................................................................ 4 

2.2 Search of Physical and Chemical Properties of Compounds.............................................. 4 

Chapter 3 General Wipe Sampling Information ............................................................................ 7 

3.1 Background......................................................................................................................... 7 

3.2 Environmental Applications ............................................................................................... 7 

3.3 Occupational Applications................................................................................................ 13

3.4 Homeland-Security Related Applications......................................................................... 13 

3.5 Other Applications............................................................................................................ 14 

3.6 Wipe Sampling Performance Information........................................................................ 14 

3.7 Miscellaneous Notes on Other Surface Sampling Methods ............................................. 16 

3.8 Summary........................................................................................................................... 18 

Chapter 4 Physical and Chemical Properties............................................................................... 19 

4.1 Chemical Agents and TICs of Interest.............................................................................. 19 

4.2 Summary........................................................................................................................... 27 

Chapter 5 Wipe Sampling Methods for CWAs and TICs............................................................ 29 

5.1 OP Pesticides/Pesticides .................................................................................................... 29 

5.2 CWAs, CWA Precursors, and CWA Degradation Products.............................................. 33 

5.3 Rodenticides....................................................................................................................... 34 

5.4 Controlled Substances........................................................................................................ 34 

5.5 Summary........................................................................................................................... 34 

Chapter 6 Summary and Data Gaps............................................................................................. 35

6.1 Summary of Available Wipe Sampling Information for Compounds of Interest............. 35 

6.2 Gaps .................................................................................................................................. 37 

6.3 Conclusions....................................................................................................................... 38 

Chapter 7 References ................................................................................................................... 39 

Appendix A Chemical Structures for the Compounds of Interest .............................................. A-1 

List of Tables 

Table 1. Summary of Resources for MSDS Information for Compounds of Interest ................... 4 

Table 2. General Uses of Wipe Sampling Techniques .................................................................. 8 

v
vi

Table 3. Physical/Chemical Properties of CWAs – Blister Agents............................................. 20 

Table 4. Physical/Chemical Properties of CWAs – Nerve Agents.............................................. 21 

Table 5. Physical/Chemical Properties of CWA Precursors and Degradation Products ............. 22 

Table 6. Physical/Chemical Properties of OP Pesticides and Other Pesticides........................... 23 

Table 7. Physical/Chemical Properties of Rodenticides and Controlled Substances .................. 25 

Table 8. Summary of Wipe Sampling Information Found in the Literature for the Compounds of 

Interest......................................................................................................................... 30 
vii

Abbreviations, Acronyms, and Symbols 

 

 

ASTM American Society for Testing and Materials 

CBIAC Chemical and Biological Defense Information Analysis Center 

CHEERS Children’s Environmental Exposure Research Study 

cm centimeter 

cm

2

 square centimeter 

cm/s centimeter per second 

Children's Total Exposure to Persistent Pesticides and Other Persistent CTEPP Organic Pollutants 

CWA chemical warfare agent 

DCM dichloromethane 

EPA U.S. Environmental Protection Agency 

FPD flame photometric detector 

ft2

 square foot 

GC gas chromatography 

HPLC high-performance liquid chromatography 

HVS3 High Volume Small Surface Sampler 

IPA isopropyl alcohol 

LC liquid chromatography 

m

2

 square meter 

mL milliliter 

mm millimeter 

MS mass spectrometry 

MSDS material safety data sheet 

NERL National Exposure Research Laboratory 

NHEXAS National Human Exposure Assessment Survey 

NHSRC National Homeland Security Research Center 

NIOSH National Institute for Occupational Safety and Heath 

OP organophosphate pesticide 

OPCW Organisation for the Prohibition of Chemical Weapons 

OSHA Occupational Safety and Health Agency 

PBDE polybrominated diphenyl ether 

PBS phosphate buffered saline 

PBT phosphate buffer with Tween 

PCB polychlorinated biphenyl 

PCP phencyclidine 

PUF polyurethane foam 

SSP swab sample processing 

TEPP tetraethyl pyrophosphate 

TIC toxic industrial chemical 

TSA Transportation Security Administration 

USDA U.S. Department of Agriculture 
viii
ix

Acknowledgements 

This report was prepared for the U.S. Environmental Protection Agency (EPA) under the 

direction and coordination of Stephen Billets of the EPA’s National Exposure Research 

Laboratory (NERL), Environmental Sciences Division, in Las Vegas, Nevada. EPA NERL 

acknowledges funding support for this project from EPA’s National Homeland Security 

Research Center (NHSRC), and specifically Oba Vincent and Rob Rothman for their 

contributions. The EPA NERL thanks the following peer reviewers for their review of this 

report: Brian Schumacher (EPA NERL); Eric Koglin (EPA NHSRC); Dan Stout (EPA NERL); 

and Kevin Ashley (Centers for Disease Control and Prevention, National Institute for 

Occupational Safety and Health). This report was prepared for the EPA by Battelle. 

Acknowledgment is given to Stephanie Buehler, who was the Battelle lead author, and to Sarah 

Attenberger, Jane Chuang, and Amy Dindal, for their contributions to the preparation of this 

report. 
x
1

Chapter 1 

Introduction 

Collection of contaminants from surfaces, referred to as “wipe sampling”, is an important 

technique for the estimation of contaminant deposition on a variety of surfaces, including those 

in buildings, homes, outdoor areas, and hands (dermal wipes). Wipe sampling techniques are 

used for environmental sampling, industrial hygiene monitoring, monitoring of remedial 

processes, security monitoring, compliance monitoring, and various other related applications. 

Examples of wipe sampling applications include testing of household surfaces for lead; airport 

luggage screening for explosives; post-remediation sampling of methamphetamine houses; 

dermal wipe sampling techniques for personal exposure to pesticides; post-decontamination 

sampling; and spill clean-up verification of environmental contaminants. These are just a few of 

the many applications of wipe sampling techniques that are applied by government agencies and 

the private sector on any given day. 

Procedures for the collection of contaminants from surfaces have several components in 

common, including the wipe sampling media, the wetting solvent, and the collection technique. 

However, wipe sampling procedures can vary widely, depending on the contaminant(s) of 

interest and the surface to be sampled. Reliability of the sample results begins with accurate 

collection of a sample for analysis. Thus, the wipe sampling procedures used for a particular 

analyte on a given surface, including the proper combination of the wipe sampling components 

described above, are an integral aspect of whether or not the results generated will be 

representative of the contamination. 

The objective of this report is to concisely summarize the findings of a literature review that was 

conducted to identify the state-of-the-art wipe sampling techniques for a target list of 

compounds. This report describes the methods used to perform the literature review; a historical 

review of wipe sampling techniques in general; a review of chemical and physical properties of 

each target analyte; an analysis of wipe sampling techniques for the target analyte list; and a 

summary of the findings, including data gaps. 
2
3

Chapter 2 

Literature Search Methods 

2.1 Literature Review

In the first task of this project, a two-phased approach was used to conduct a literature review to 

determine what is already known about wipe sampling techniques for a target list of analytes. 

First, a broad search was conducted that explored what general information was available on 

wipe sampling (i.e., how different organizations are using wipe sampling). This search did not 

focus on the specific compounds of interest for this project, but instead focused on what wipe 

sampling procedures could be found for various government agencies or other groups. Extensive 

internet searching was used as the primary tool for this phase of the review process. Various 

government agency websites were also searched using the available search options on that site 

using keywords such as “wipes(s)” or “wiping” and “sample(s)”. The following government 

agency websites were included in the search: Drug Enforcement Administration, Federal Transit 

Administration, Occupational Safety and Health Administration (OSHA), National Institute for 

Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention, Bureau 

of Alcohol, Tobacco and Firearms, Coast Guard, Consumer Product Safety Commission, U. S. 

Department of Agriculture (USDA), U.S. Department of Defense, U.S. Department of Homeland 

Security, U.S. Department on the Interior, Agency for Toxic Substances and Disease Registry, 

Federal Aviation Administration, Transportation Security Administration (TSA), Federal Bureau 

of Investigation, Food and Drug Administration, National Aeronautics and Space 

Administration, National Institute of Standards and Technology, the U.S. Army Corp of 

Engineers, and the U.S. Environmental Protection Agency (EPA). These agencies and 

departments were selected because they seemed most likely to conduct wipe sampling for some 

branch of their operations. In spite of this effort, only limited information was obtained from this 

search process. 

As a subset to this search, the Federal Register was explored to see if any further information 

could be obtained on the agencies listed above. It was determined that this approach was not 

productive as little practical information was found. 

In the second phase of the literature search, information was sought on wipe sampling as it 

relates to the compounds of interest. These focused searches were conducted by using databases 

available through a regular library system as well as by the Chemical and Biological Defense 

Information Analysis Center (CBIAC), which has special access to documents related to 

chemical, biological, radiological, and nuclear technology information. Searches were 

conducted using keywords similar to the following: 

wipe OR wipes OR wiping AND sample OR sampling AND compound 
4

Each compound being investigated was included in individual searches. CBIAC searches 

focused on the chemical warfare agents (CWAs) and related compounds; the library database 

searches focused on the remaining compounds (pesticides and other toxic industrial chemicals 

(TICs). These searches yielded more than 140 references. The references were reviewed further 

for information regarding wipe sampling methodology, covering areas such as wipe material, 

wetting solvent, wipe procedure, and sampling surface. As a result of this further examination, 

only 39 citations were deemed relevant to this study and are included as references in this report. 

As part of the overall reference collection effort, knowledgeable experts in the field of wipe 

sampling were contacted and relevant references were gathered based on their suggestions and 

input. 

2.2 Search of Physical and Chemical Properties of Compounds 

Part of the literature review also included gathering physical and chemical property information 

on each of the compounds of interest. Specifically, material safety data sheets (MSDSs) were 

collected from various publicly available internet sites as shown in Table 1. Information from 

the MSDSs was compiled into tables in Chapter 4. When the information contained on the 

MSDS seemed sparse, physical property information for a particular compound was crosschecked using CHEMINFO (through the Canadian Centre for Occupational Health and Safety 

(CCOHS)) and Ecotoxnet (http://extoxnet.orst.edu/). MSDS information from a subscription 

service (OHS at www.ohsworks.com) was also used. For the CWAs, information on chemical 

and physical properties was also obtained from two literature sources (1,2), in which detailed 

information on these compounds had been collected and summarized. The chemical structures 

for each of the compounds of interest are provided in Appendix A. 
5

Table 1. Summary of Resources for MSDS Information for Compounds of Interest 

Compound CAS No. Resource

 Chloropicrin 76-06-2 www.e1.greatlakes.com/common/msdspdf/00026.pdf 

 Dichlorvos 62-73-7 http://www.cdc.gov/niosh/ipcsneng/neng0690.html

 Dicrotophos 141-66-2 http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryldicrotophos/dicrotophos-ext.html 

 Dimethylphosphite 868-85-9 http://www.cdc.gov/niosh/ipcsneng/neng1599.html

 Distilled Mustard 505-60-2 http://www.gulfweb.org/bigdoc/report/apphd.html 

(HD)/Mustard Gas (H) 

 1,4-Dithiane 505-29-3 http://physchem.ox.ac.uk/MSDS/DI/1,4-dithiane.html 

 Mustard (HT) 172672-28-5 http://chppm-www.apgea.army.mil/dts/docs/detht.pdf

 Ethyldichloroarsine (ED) 598-14-1 http://environmentalchemistry.com/yogi/chemicals/cn/E

thyl%A0Dichloroarsine.html 

 Fenamiphos 22224-92-6 http://www.cdc.gov/niosh/ipcsneng/neng0483.html

 Lewisite (1) 541-25-3 http://www.uscg.mil/mlclant/KDiv/Envrn%20Hlth/IHMSDS/MSDS/LewisiteMSDS.doc 

 Lewisite (2) 40334-69-8 MSDS not available; information presented from: 

http://www.epa.gov/opptintr/aegl/pubs/rest133.htm

 Lewisite (3) 40334-70-1 MSDS not available; information presented from:

http://www.epa.gov/opptintr/aegl/pubs/rest133.htm

 Methyl parathion 298-00-0 http://www.cdc.gov/niosh/ipcsneng/neng0626.html

 Mevinphos 7786-34-7 http://pmep.cce.cornell.edu/profiles/extoxnet/metirampropoxur/mevinphos-ext.html 

 Nicotine 54-11-5 http://physchem.ox.ac.uk/MSDS/NI/nicotine.html

 Phencyclidine 77-10-1 http://www.cerilliant.com/search.htm

(search cat no P-001) 

 Phorate 298-02-2 http://www.piindustries.com/tech_main.htm

 Sarin (GB) 107-44-8 http://www.gulfweb.org/bigdoc/report/appgb.html 

 Soman (GD) 96-64-0 http://www.gulfweb.org/bigdoc/report/appgd.html 

Cyclohexyl sarin (GF) 329-99-7 MSDS not available; information presented from: 

Abercrombie, PL (September 2003) 

 Strychnine 57-24-9 http://www.cdc.gov/niosh/ipcsneng/neng0197.html

 Tabun (GA) 77-81-6 http://www.gulfweb.org/bigdoc/report/appga.html 

 Tetraethyl pyrophosphate 107-49-3 http://www.segulab.com/en/t_msds.htm

(TEPP) 

 Thiodiglycol 111-48-8 http://www.cdc.gov/niosh/ipcsneng/neng1601.html

 1,4-Thioxane 15980-15-1 http://www.fluorochem.net/msds.asp?txtCatNo=001450

&x=25&y=6 (search for cat no 001450) 

 Trimethyl phosphite 121-45-9 http://www.osha.gov/SLTC/healthguidelines/trimethylp

hosphite/recognition.html

 VX 50782-69-9 http://www.gulfweb.org/bigdoc/report/appvx.html 

Crimidine 535-89-7 http://yosemite.epa.gov/oswer/ceppoehs.nsf/profiles/535

-89-7?opendocument 

Methyl fluoroacetate 453-18-9 http://www.fluorochem.net/msds.asp?txtCatNo=006800

&x=29&y=10 (search for cat no 006800) 
6
7

Chapter 3 

General Wipe Sampling Information 

3.1 Background

Wipe sampling is one of the primary techniques for assessing surface contamination. When using 

the appropriate wipe sampling media coupled with an appropriate solvent (or used dry, as 

warranted), the type and amount of chemical on a particular surface can be identified by wiping a 

sufficient area of the surface and analyzing the wipe. This technique is a quick and easy means 

of determining what chemicals reside on a surface. Though wipe sampling is often employed, 

the methods and materials associated with wipe sampling vary greatly. Most wipe sampling 

procedures are a manual process, and the pressure applied for each wiping procedure could vary 

significantly among field operators. Different government agencies use different wipe methods 

for various compounds. Even within a particular field (such as occupational exposure 

assessments), variations in wipe sampling methodologies have been reported. 

In this section, the general uses of wipe sampling techniques by different government agencies, 

various researchers, and studies are described in three primary areas: environmental, 

occupational, and homeland security-related applications. This information is summarized in 

Table 2. Performance information on wipe sampling methods is provided in Section 3.6. This 

chapter is meant to provide only a brief overview of wipe sampling applications and performance 

data. It is not meant to provide exhaustive coverage of all available studies but rather a synopsis 

of relevant information that describes what wipe sampling methods have been performed by 

various organizations to help establish the credibility of wipe sampling as a useful technique. 

3.2 Environmental Applications

Wipe sampling is an integral part of the sampling protocol for many environmental assessments 

including evaluating remedial progress, environmental compliance, and for human exposure 

monitoring. A review of the literature for wipe sampling techniques in these areas is described in 

this section. 

EPA has devised wipe sampling methods for polychlorinated biphenyl (PCB) analysis (3, 4). 

This technique is used to verify PCB cleanup on hard, smooth, non-porous surfaces. In this 

application, filter papers (such as Whatman 40 ashless or Whatman 50 smear tabs) or a gauze 

pad are used for the wipe material. The wipes are wetted with a solvent, such as isooctane or 

hexane, held with forceps or rubber gloves, and rubbed over a 100 square centimeter (cm2

) area. 

 
8

Table 2. General Uses of Wipe Sampling Techniques 

Agency or Agency 

Compound Affiliation Wipe Material Wetting Solvent Wipe S

Pesticides polar pesticides ASTM cotton gauze pads IPA 

smooth, no100 cm2 

malathion ASTM cotton gauze pads isooctane, DCM 

smooth, no100 cm2 

2,4-D 

EPA gauze pads 

70:30 phosphate buffer:acetonitrile; IPA 

uncarpeted table tops, sills, carpe

- 2m2 

ASTM cotton gauze pads isooctane 

smooth, no100 cm2 

EPA, New JerseyDepartment of 

chlorpyrifos Environmental 

Protection gauze pads DI water 

carpet; 100 

2 cm 

New Jersey Department of Environmental Protection and Energy gauze pads DI water turf; 100 c

hard floors

chlorpyrifos, diazinon EPA gauze pads IPA surfaces 

EPA gauze pads DI water window si

Other Organics PCBs 

EPA filter paper, gauze pad isooctane, hexane 

hard, smooporous; 10

NIOSH glass wool filter hexane 

hard, non-pft2 

general 1 filter paper dry, water 

floors, wal

2 cm 

general 1 Kleenex® dry, water 

floors, wal

2 cm 
9

Table 2. (continued) 

Compound 

Agency or Agency 

Affiliation Wipe Material Wetting Solvent Wipe S

PCBs 

general 1 Cloth wipes octane NA general 1 Whatman filter paper hexane 

ventilation ft2 

general 1 Whatman smear tabs methanol 

work and tsurfaces; 1

ASTM cotton gauze pads hexane, isooctane 

smooth, no100 cm2 

organic residues USDA gauze pads IPA 100 cm2 tetrachlorophenol general 1 gauze pads NA 

wood; 231 

chlorophenols general 1 Whatman filter paper NA wood 2,4-ditertbutylphenol general 1 cotton swabs ethanol rubber 2,3,7,8-tetrachlorodibenzo-pdioxin 

general 1

Whatman glass microfiber 

paper none 

laboratory 625cm2 

Metals As, Cu, Cr EPA 

TexWipe TX1009 clean roomwipe (100% polyester) 

DI water, 0.9% saline 

wood; 314 

Pb, Be, As, Cd, Cr, Ni 

Brookhaven National Lab/NIOSH 

cotton gauze pads, ashless filter paper, GhostWipesTM

DI water, IPA, ethanol, methanol, hexane 

metal, plaswood, con

2 cm 

Pb 

ASTM Disposable towellete pre-moistened 1 ft2 general 1 Wash'nDry® paper towels pre-moistened 

household 1 ft2 

EPA Swiffer® dry and wet cloths pre-moistened floors, win
10

Table 2. (continued) 

Compound 

Agency or Agency 

Affiliation Wipe Material Wetting Solvent Wipe S

Othersmethamphetamine 

MN State Department of Health gauze sponge methanol 

dry, hard, nporous; 10

WA State Department of Health filter paper methanol 

dry, hard, nporous; 10

anthrax general 1 Swipe, Heavy Wipe, swab PBT 

vinyl, tile, laminate, m

2 cm 

general 1 rayon gauze pad, swab water, PBS hard surfac

1 No particular agency was found to be affiliated with the referenced study. 

NA = Not Available. DCM = dichloromethane IPA = isopropyl alcohol PBT = phosphate buffer with 0.05 percent Tween PBS = phosphate buffer saline
11

Other PCB wipe methods are used to determine the extent of PCB contamination. PCB 

contamination on walls and transformers has been determined by the National Institute for 

Occupational Safety and Heath (NIOSH) using glass wool filter wipes wetted with hexane over a 

1 square foot (ft2

) area (5). Other studies by various researchers have used filter paper and 

Kleenex®, cloth wipes, Whatman filter paper, and Whatman smear tabs as a sampling medium. 

These wipes have been used dry, and saturated with octane, hexane, and methanol, respectively. 

The areas wiped range from 100 cm2

 to 900 cm2 (5). 

Wipe sampling for metals such as lead or arsenic is also routinely done. In a wipe comparison 

study to determine the dislodgeable arsenic, copper, and chromium residues on chromated 

copper arsenate treated lumber, EPA used the following wipe media: a TexWipe TX1009 clean 

room wipe (100 percent polyester) that was saturated with deionized (DI) water, the same 

polyester wipe moistened with 0.9 percent saline solutions at two times the dry weight of the 

wipe, and an acid-washed polyester wipe saturated with DI water, though this particular wipe 

was found to contain traces of the acid wash still in the wipe (6). Wiping was done using a 1.1 

kilogram disc that was approximately 8.5 centimeter (cm) in diameter, as a wiping block. 

The American Society for Testing Materials (ASTM) has a lead-specific wipe sampling standard 

method for collecting settled dust on surfaces in and around buildings (7). A packaged, 

disposable towellette that is pre-moistened with a wetting solvent is used for the sample 

collection. Overlapping “S” and “Z” patterns are used when collecting the sample from an area 

of 100 cm2. 

The Industrial Hygiene Group at Brookhaven National Laboratory uses NIOSH Method 9100 

(posted at www.cdc.gov/niosh/nmam) to determine lead and other metals in surface residue (8). 

A range of wipe materials can be used. Either 2" x 2" or 4" x 4" cotton gauze pads; ashless filter 

paper (1.5 to 4 inches in diameter); or pre-moistened wipes such as GhostWipesTM are 

appropriate for lead, beryllium, arsenic, cadmium, chromium, or nickel sampling. 

Approximately 1-2 milliliters (mL) of solvent such as DI water, isopropanol (IPA), ethanol, 

methanol, or n-hexane is used with the wipe. A 100 cm2

 area is supposed to be sampled by this 

method. The solvent used does not appear to be critical for the metal collection, but can impact 

the sampling surface and should be chosen accordingly. 

Other commercially available wipes have also been used for lead sample collection. 

Wash’nDry® disposable paper towels, moistened with 20 percent denatured alcohol and 1:750 

benzalkanium chloride have been used to collect lead dust from general household surfaces (5). 

Other researchers have used methods similar to the NIOSH Method 9100 described previously. 

EPA is currently exploring the potential use of dry electrostatic cloths (Swiffer®), as well as wet 

Swiffer® cleaning pads, for collecting residual dust samples after lead-based paint abatement 

cleaning (9). 

Sampling for organic compounds is an important component of many exposure assessments. 

ASTM offers a method for taking wipe samples from smooth, non-porous surfaces for organic 

compounds (10). ASTM recommends the use of sterile, surgical cotton gauze pads (7.6 cm2

) 

with pre-cleaning only when necessary. Wipe wetting solvents are recommended on a 

compound basis. For example, for PCBs and most pesticides, isooctane is recommended (54 to 
12

80 percent recovery). Hexane can also be used in wipes for PCBs. For carbamates or polar 

pesticides, IPA is an appropriate solvent for use with the wipe (84 to 96 percent recovery). 

Acetone is not desirable because it can remove interfering compounds from the sampling 

surface. A 100 cm2

 wiping area is recommended as is 2 mL of any solvent that is used to wet the 

wipe. The area should be wiped vertically and then horizontally using firm strokes with minimal 

overlap. 

The USDA also has a published wipe sampling method for detecting organic residues or dusts 

from surfaces (11). As with the ASTM method, their technique uses a 3" x 3" sterile gauze pad 

moistened with IPA. A 100 cm2

 area is also sampled. 

EPA has conducted multiple exposure studies where wipe sampling for organic compounds on 

household surfaces played a key role in the assessment. As part of the Children’s Total 

Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study 

assessing children’s exposures to particular persistent organic pollutants, such as chlorpyrifos 

and polycyclic aromatic hydrocarbons, wipe samples were taken for residues on hard floors 

using pre-cleaned, 4" x 4" Johnson and Johnson (J&J) SOF-WICK gauze pads moistened with 2 

mL of 75 percent IPA in DI water (12). The J&J SOF-WICK gauze pads were also used in the 

National Human Exposure Assessment Survey (NHEXAS) exposure study in collecting wipe 

samples for chlorpyrifos and diazinon from window sills. In this case, the wipes were moistened 

with 2 mL of DI water and were also pre-cleaned with methylene chloride prior to their use (13). 

Window sills were wiped in this study by wiping the length of the sill using moderately firm 

pressure. After wiping the sill in one direction, the wipe was folded in on itself and the sill was 

wiped in reverse. 

EPA’s Children’s Environmental Exposure Research Study (CHEERS) pilot study also used 

gauze pads for wipe sampling to determine children’s exposure to various pesticides, phthalates, 

polybrominated diphenyl ethers (PBDEs), and fluorinated compounds. At the time of this study, 

however, the J&J SOF-WICK gauze pads had been discontinued, so an alternative, Kendall 

Excilon wipes were used instead. The wipes were the same size as the J&J brand wipes and 

were also pre-cleaned prior to use with dichloromethane (DCM). They were saturated with 10 

mL of IPA before a sample was taken. This amount of IPA has the potential to extract more of 

the compounds from the surface and sub-surface of the sample area than are otherwise available 

for human contact and thus dermal absorption. 

Black et al. (14) also used wipe samples for measuring dislodgeable chlorpyrifos residues on 

Kentucky bluegrass turf. The wipes were pre-extracted 7.6 cm x 7.6 cm gauze pads sprayed with 

DI water. A 100 cm2

 area was sampled based on Occupational Safety and Health Agency 

(OSHA) methods. Specifically, the area was wiped with one pad in a single direction for 10 

strokes. Wipe samples recovered 1 percent to 6 percent of the initial chlorpyrifos deposit from 

the turf (1 to 3 hours after application). Wipe sampling variability ranged from 37 to 74 percent 

between different studies performed during the research. Within a particular study, wipe 

sampling variability averaged 21.5 percent. 

Nishioka et al. wiped uncarpeted floors, table tops, and window sills using J&J SOF-WICK 

cotton gauze dressing sponge moistened with 2 mL of sweat stimulant (70:30 phosphate 
13

buffer:acetonitrile) (15,16). An area from 850 cm2 to 2 m2 was sampled by first wiping in one 

direction, then folding the wipe in on itself, and then wiping the same area in an orthogonal 

direction. 

Multiple other methods of wipe samples for various compounds have been used over the years, 

as noted by McArthur (5). Wooden surfaces (231 cm2) were sampled for tetrachlorophenol with 

12-ply surgical pads using 10 strokes for each of four samples. Chlorophenols were also 

collected from wooden surfaces using Whatman 1 filter paper (4.25 cm) with a 300 gram weight 

placed on top. Surface contamination of rubber with 2,4-ditertbutylphenol was determined using 

ethanol-soaked cotton swabs. 2,3,7,8-tetrachlorodibenzo-p-dioxin contamination of laboratory 

surfaces was found by wiping a 625 cm2 area with dry Whatman glass microfiber paper. 

3.3 Occupational Applications 

Wipe sampling is an important component of occupational exposure analysis. OSHA has 

multiple wipe sampling methods and recommendations depending on the chemical of interest. 

OSHA has developed guidelines to provide chemists with a uniform method of evaluating 

surface sampling wipes (17). As part of these guidelines, information on how to properly 

conduct wipe sampling is presented. Among the steps is selecting a sampling medium. OSHA 

recommends the following list of media for wipe sampling: DURX 670 (polyester and cellulose), 

Pro-Wipe 880 (polypropylene), Ghost Wipes (cross linked polyvinyl alcohol), AlphaWipes 

(polyester), and even charcoal impregnated discs. Various wetting agents are also 

recommended: DI water for metals, DI water or IPA for non-volatile organics, or other solvents 

if the compound being sampled will react with water or IPA. The guidelines also indicate that 

the ideal sampling surface is a smooth and non-porous, and that the sampling area should be 100 

cm2

. 

OSHA has also prepared a chapter in their Technical Manual with more detailed information 

about wipe sampling (18). Similar to the previous document, each step of the wipe sampling 

procedure is discussed. Particular attention is paid to the media choice for sampling a surface. A 

filter is described as the classic wipe sampling technique. Paper filters, mixed cellulose ester 

filters, and smear tabs are best for metals. For things that are unstable on paper filters, polyvinyl 

chloride filters are recommended. Squares of a gauze material that are used either wetted (with 

solvent or water) or dry are purported to be best for organic compounds while volatile solvents 

are best sampled with charcoal impregnated pads. To sample a surface for isocyanates or 

aromatic amines, a filter treated with derivitizing reagent is recommended. Glass fiber filters, 

either wetted or dry, are recommended for many of the chemicals that will be analyzed by gas 

chromatography (GC) or high-performance liquid chromatography (HPLC). 

3.4 Homeland-Security Related Applications 

Over the last five years, the increased focus on homeland-security related techniques has 

generated new applications for wipe sampling. For example, airport luggage is screened by wipe 

sampling followed by ion mobility spectrometry analysis for explosives detection. In recent 

years, the detection of anthrax has become a critical analytical need. More specifically, the 

determination of whether or not any anthrax remains in a building after building decontamination 
14

has become an important use for wipe sampling. Buttner et al. (19) tested the efficiencies of 

decontamination strategies for b. anthracis by taking wipe samples of vinyl tile, wood laminate, 

and metal surfaces after a simulated dispersion and subsequent decontamination. Three different 

kinds of wipe samples were used: (1) a Swipe (Speci-sponge) moistened with 30 mL of 0.01M 

phosphate buffer with 0.05 percent Tween (PBT); (2) a Heavy Wipe (Handy Wipes) moistened 

with 40 mL of PBT; and (3) a swab sample processing (SSP) kit moistened with 20 drops of 

buffer. In all cases, a 929 cm2

 area was sampled. For the Swipe and Heavy Wipe samplers, the 

surface was sampled by wiping the area in a horizontal direction. The wipe was then turned over 

and the unused surface was used to sample the same area while wiping in a vertical direction. 

For the SSP kit, the foam swab was used to sample the first half of the pre-moistened surface, 

then the swab was turned over and the remaining half of the surface was sampled. Removal 

efficiencies were not presented for any of the methods used in this study, but all three wipe 

materials collected similar levels of the b. anthracis surrogate used during testing, and similar 

levels of the bacteria were obtained from all three surfaces tested. 

In another study by Sanderson et al. (20), two different b. anthracis sampling methods were 

tested. Wipe samples were taken using actual wipes as well as a swab. The wipe was 7.62 cm x 

7.62 cm sterile rayon gauze pad that was wetted with 5 mL of sterile water. The sampling area 

was first wiped using vertical strokes, the wipe was then folded in on itself and the area was 

wiped using horizontal strokes. The swab was a sterile, rayon swab that was moistened with 

phosphate buffered saline (PBS) at pH 7.2. Several strokes of the area were first taken with the 

swab. The swab was then rotated during sampling to ensure that all of the swab was used. Dry 

swab samples were also taken. Samples were collected from air ducts, machinery, window 

boxes, and mail sorting bins from a postal facility (all non-porous surfaces). Wet swabs 

performed better than dry, detecting b. anthracis in 54 percent vs. 14 percent of the instances. 

Wipe sampling detected b. anthracis in 87 percent of the instances. 

3.5 Other Applications

Illegal methamphetamine labs have become a serious problem for many cities and states. Wipe 

sampling methods for methamphetamines were found for two state departments, the Minnesota 

Department of Health (along with the Minnesota Pollution Control Agency) and the Washington 

State Department of Health (21, 22). Though both methods used 2 mL of methanol as the 

wetting solvent for their wipes, the wipe material itself was quite different for the two states. 

Minnesota used a 3" x 3" general use gauze sponge while Washington used filter paper. In both 

cases, a dry surface was to be sampled. The Washington State procedure specified a hard, nonporous surface be sampled; this was implied in the Minnesota protocol. An overlapping “Z” and 

“N” pattern are used for sampling. 

3.6 Wipe Sampling Performance Information 

The wipe sampling studies presented in this chapter mainly discuss applications of wipe 

sampling. While various applications are important in verifying the validity of the technique, it 

is also important to discuss and understand the validation and performance of the sampling 

methods. Some studies have focused on determining performance criteria for various wipe 

sampling methods. 
15

Chavalitnitkul et al. (23) conducted an evaluation of wipe sampling variability using lead oxide 

dust as the test contaminant. This study aimed to evaluate wipe testing methods in general as 

well as the OSHA wipe testing method, more specifically, for quantitative recovery and 

repeatability. The study used moistened Whatman filter paper, commercial paper towels, 

adhesive paper labels, and adhesive tape as wipe media. Formica (a non-porous, smooth surface) 

and plywood (a rough, porous surface) were tested. Personal variations in performing wipe 

sampling were first tested using 12 different individuals to collect samples. A wide variation in 

removal efficiencies was found across participants, indicating potential issues in duplicating 

sample results between field staff. Much of the variation was caused by the pressure applied 

during sampling as well as the lack of a consistent sampling area. Removal efficiencies ranged 

from 31 percent to 212 percent across the 12 samplers in this portion of the study. The degree of 

sample variation decreased when the area to be sampled was measured prior to sampling, thus 

allowing for a consistent sampling area across all samples. 

In evaluating the different wipe media and wipe surfaces, as described earlier, Chavalitnitkul et 

al. (23) found that most Whatman filter paper and moist paper towels gave similar, and good, 

removal efficiencies (80 to 90 percent). The surface sampled, however, was found to have a 

significant impact on the removal efficiency of the wipe sample. The smooth, non-porous 

surface (Formica) showed better removal efficiencies than the rough, porous surface (plywood). 

Removal efficiencies ranged from 57 percent to 91 percent across all sampling media and 

various applied pressures on formica, while efficiencies ranged from 30 percent to 77 percent on 

plywood. For plywood, the adhesive tapes gave better removal efficiencies than the paper towels 

or Whatman filters used. Applying the maximum pressure while sampling increased the removal 

efficiency of the adhesive media on both surfaces, but provided little impact for the paper towel 

and Whatman filter. 

As part of another lead dust study, Vostal et al. (24) evaluated the efficacy of the wipe sampling 

procedure using moist, disposable paper towels on household floors. They found low variability 

between wipe samples and across four different investigators, indicating that the amount of lead 

obtained by these wipe samples could be reliably reproduced. 

As McArthur describes (5), others have also explored the effect of wipe media, surface, and wipe 

techniques on the wipe sampling collection efficiency. They have determined, as Chavalitnitkul 

et al. (23) did, that wipe sampling removal efficiency decreased for rough surfaces. Variation 

was also found between samples taken by different individuals when the sampling area was 

estimated instead of measured. 

Fenske et al. (25) evaluated the applicability of wipe sampling to determine exposure to 

pesticides in indoor environments. They sampled chlorpyrifos using a surgical gauze pad wetted 

with either distilled water or IPA. Wipe samples were taken on carpet and aluminum foil 

surfaces. Wipe samples were taken using a modification of the OSHA method where a 100 cm2

area was wiped with three strokes in one direction, then a second gauze pad was used to wipe the 

same area in an orthogonal direction. Removal efficiency was 86 percent to 96 percent from the 

spiked aluminum foil samples with low variability between the different technicians taking the 

samples. For wipe samples taken on carpeted surface, the variability was much higher, 40 
16

percent to 60 percent. Fenske et al. (25) concluded that much of this variability was related to 

the deposition of the pesticide onto the carpet, not the wipe sampling itself. They further 

concluded that wipe sampling provides a simple way of estimating the pesticide residues on a 

surface, but precision for the method could be improved by defining the wipe area and 

standardizing materials and methods. 

3.7 Miscellaneous Notes on Other Surface Sampling Methods 

As noted from the studies discussed in this section, wipe sampling can involve various materials 

and be used on a variety of surfaces. There are a couple of related sampling techniques that 

warrant mentioning here, but that do not address the surface wipe sampling that is the focus of 

this report. Dislodgeable residues from carpets can be determined using wipe sampling, as 

discussed previously; however, the preferred method of collecting dust samples from carpets is 

using vacuum sampling. For exposure studies a High Volume Small Surface Sampler (HVS3) is 

generally used for such a purpose. This is essentially a modified vacuum that uses cyclonic 

action to collect dust particles from the carpet into an attached sampling container. A sample is 

taken by vacuuming a given area with overlapping path lengths. An ASTM standard method is 

available for this technique (26). 

EPA studies have also used a polyurethane foam (PUF) roller sampler to determine dislodgeable 

or transferable residues from floors (15-16, 27-29). The PUF roller generally consists of an 

aluminum frame with aluminum wheels. A PUF sleeve is the placed on the frame and the 

sample is taken by rolling the sampler back and forth over the selected 100 cm traverse path. 

This technique was used in CTEPP where a 7.6 cm thick pre-cleaned PUF was used on the roller. 

One EPA study compared the PUF roller to the Dow drag sled and the California cloth roller 

methods to determine which was best at estimating the transfer of chlorpyrifos to carpets and 

vinyl flooring to skin (27, 28). The PUF roller used in this study is similar to the one discussed 

previously. The PUF sleeve used in the EPA comparison study measured 90 millimeter (mm) 

outer diameter x 30 mm inner diameter x 76 mm length. A 100 cm sample length was used, with 

sampling consisting of one forward and one backward pass of the length. The roller was 

operated at a rate of 10 centimeters per second (cm/s). The drag sled device consisted of a 3" x 

3" piece of 3⁄4" plywood as the base with an 8 pound weight mounted on top. A pre-cleaned 4"x 

4" undyed denim cloth was used on the underside as the sampling media. The sled was pulled by 

a wire along a 48 inch path at a rate of 10 cm/s. The California roller device resembled a large 

rolling pin made of polyvinyl chloride pipe. The pipe was 63 cm long, 13 cm in diameter 

covered with 1 cm thick foam, and filled with steel ball bearings. A 17" x 17" pre-cleaned 

percale sheet cloth (50 percent cotton, 50 percent polyester) was used to collect the sample by 

placing the cloth on the sampling area, covering it with the plastic, and pushing the roller over it. 

The study found the drag sled and PUF roller to be better methods than the cloth roller technique. 

All three methods had reasonable precision (24 to 46 percent). Transfer efficiencies ranged from 

2 percent to 7 percent, with the drag sled method averaging 2.1 percent. 

 

Other exposure studies have also relied on the PUF roller for sampling. Nishioka et al. (15-16, 

29) used the sampler to determine the available dislodgeable residue or surface dust of 2,4-D on 

indoor carpets. The PUF sleeves used were 8 cm long x 8 cm outer diameter. The PUF was pre-
17

cleaned before use with water and then 70:30 volume/volume acetonitrile:phosphate buffer. In 

one of these studies, the PUF was moistened with a 70:30 phosphate buffer:acetonitrile mixture 

that simulates human sweat, allowing the PUF roller to simulate a child’s hand contact with the 

sampling surface. A 0.48 m2

 area was sampled at a rate of approximately 17 cm/s. The PUF 

roller provided transfer efficiencies of 0.1 percent to 0.2 percent. 

In a study by Lu and Fenske (30), the PUF roller method was compared to wipe sampling to 

determine which was better at simulating hand pick-up of chlorpyrifos residues from carpet. The 

PUF sleeve used was 8 cm in length and sampling was conducted over a 100 cm length (total of 

800 cm2

 area) using techniques similar to those described previously. The PUF sleeve was 

misted with DI water before use. The wipes used in this study were 12-ply 7.6 cm x 7.6 cm 

surgical gauze pads. They were also moistened with DI water before sampling was conducted. 

In this case, a 100 cm2 area was wiped. The area was first wiped with three strokes, and then the 

sampling was repeated with a second pad in the orthogonal direction. Results showed that 

chlorpyrifos residue transfer as measured by these methods was 23 to 36 times greater than that 

found from normal carpet to skin transfers. 

The Minnesota Children’s Pesticide Exposure Study compared two different surface sampling 

methods to determine which better represents realistic estimates of exposure (31). Malathion, 

atrazine, diazinon, and chlorpyrifos were measured using the Edwards and Lioy (EL) sampler 

and the Lioy, Wainman, and Weisel (LWW) surface wipe sampler. The EL sampler is a press 

sampler designed to collect surface dust from carpets or other surfaces. C18 filters were used 

and a 150 cm2 area was sampled. Samples were collected from both carpet and another noncarpeted surface. The LWW sampler consisted of a C18 impregnated Teflon filter wetted with 

IPA and placed on a pressure plate. A sample was taken by sliding the sampler the length of a 

100 cm2 template three times. Wipe samples from smooth surfaces were collected in this 

manner. The LWW sampler was determined to not be representative of pesticide residues found 

on a child’s hand from dermal contact with contaminated surfaces. The EL sampler, because it 

uses only a single hand press, represents what dislodgeable residues are available via one hand 

contact on the surface, not the total amount that might end up on a child’s hand. 

Other techniques for assessing surface contamination include directly applying a sensing 

instrument at or near the surface. Some examples of direct sensing techniques include: X-ray 

fluorescence devices for metals detection, radiation meters for determining radioactivity, and 

portable photoionization monitors for detecting volatile organic compounds. The application of 

these direct-sensing techniques is usually limited to: qualitative (e.g., presence/absence) results, 

higher detection limits, analyte selectivity, and availability of detection capability for the target 

analyte. For these reasons, wipe sampling techniques are typically used in conjunction with or 

instead of direct sensing techniques. For example, as noted previously, the TSA often collects 

wipe samples of passengers’ luggage and then tests the wipes for explosives residue using ion 

mobility spectrometry, a direct-sensing technique. Because we regard this as more of a directsensing method rather than a wipe sampling method, this technique was not researched as part of 

this report. 

For many studies, it is important to understand what amount of contaminants a person has 

transferred from the surface to his hands. Hand wipe samples or dermal wipes have therefore 
18

played a major role in many exposure studies. Dermal wipes generally consist of some sort of 

gauze sponge or cloth being used as the wipe, the wipe being wetted, and then the hand being 

thoroughly wiped. For the CTEPP study, pre-extracted gauze pads, the same as those used for 

surface wipes, were wetted with 2 mL of 75 percent IPA in DI water and used for hand wipe 

samples (12). NHEXAS dermal wipes were similar but used 4 mL of IPA (13). OSHA 

recommends the use of glass fiber filters, mixed cellulose ester filters or smear tabs, gauze 

sponges, or charcoal impregnated pads moistened with either DI water or a 50 percent solution of 

IPA in water (18). McArthur (5) notes the use of ethyl alcohol for dermal wipe samples. 

Though dermal wipes do not measure the contaminated surface, they can provide a more 

accurate assessment of a person’s exposure to a chemical. 

3.8 Summary 

Numerous wipe sampling methods were found for different government agencies, such as EPA, 

OSHA, and NIOSH, and for various sampling studies that have been conducted by different 

researchers. Wipe media ranged from gauze sponges to Whatman filters to pre-wetted, 

commercially-available wipes. Wipe sampling methods were found for various compounds, 

such as metals, PCBs, drugs, and pesticides. 

Wipe sampling provides a simple way of testing for contamination on a particular surface and 

can provide information on the mass of a contaminant on the surface. However, variability in 

reproducibility and removal efficiencies can result from the lack of standardization within a 

particular wipe sampling method as well as across various other methods. Simply clearly 

measuring the area to be sampled can significantly lower this variability. Different surface 

characteristics can also affect wipe sampling efficiency. It is therefore important that a wipe 

sampling method be fully validated before it is used so that such performance parameters, as 

discussed here, can be determined and improved. 
19

Chapter 4 

Physical and Chemical Properties 

4.1 Chemical Agents and TICs of Interest 

Wipe sampling methods exist for a variety of situations and a diverse number of chemicals. The 

focus of this report, however, is on a select set of compounds. Table 1 lists the compounds of 

interest to EPA that are the subject of this literature review. The ultimate goal of this review is to 

determine what wipe sampling methods are available and have been used for these compounds. 

Before that can be done, however, it is important to better understand the compounds listed in 

Table 1. To this end, the physical and chemical properties of each of the compounds of interest 

listed in Table 1 have been obtained, as available, for this report. The chemical structure of each 

compound has also been collected. The structures are provided in Appendix A. 

 

Tables 3 through 7 provide a summary of some of the physical properties listed in the MSDS 

information that was obtained. Characteristics that are provided where available include the 

chemical family that the compound belongs to; the physical state of the compound; its molecular 

weight and formula; boiling, freezing, and melting points; vapor pressure and density; and 

solubility. The information listed in Tables 3 through 7 was gathered from the MSDSs listed in 

Table 1, two other primary references that were used to fill in gaps in the information (1, 2), and 

those references discussed in Chapter 2. 

There are essentially two major classes of compounds in the following tables: organophosphate 

(OP) pesticides and CWAs and related compounds (e.g., CWA precursors and degradation 

products). A couple other compound classes round out the list, such as rodenticides and 

controlled substances, but the OP pesticides and CWAs and related compounds comprise 83 

percent of the compounds of interest to this literature review. Within the group of CWAs, there 

are two different types: blister agents (see Table 3) and nerve agents (see Table 4). HD, H, HT, 

Lewisite, and ED are all blister agents. Blister or vesicant agents produce burns and blisters on 

the skin of those who come in contact with them. The mustard agents (HD, H, and HT) are 

chemically stable. They are not very soluble in water, but that which does dissolve in water can 

hydrolyze very quickly. HT is actually a mixture of 60 percent H and 40 percent T (a closely 

related mustard). Lewisite and ED are organic arsenicals. They have similar properties to the 

mustard agents but they contain arsenic instead of the sulfur found in mustard agents. Lewisite 

is often found as a mixture of isomers (Lewisite 1, 2, and 3) and is only slightly soluble in water. 
20

Table 3. Physical/Chemical Properties of CWAs – Blister Agents 

Compounds CAS # Chemical Class 

Physical 

State 

Molecular 

Weight 

Molecular 

Formula 

Boiling 

Point 

Freezing 

Point 

Melting 

Point 

Mustard Gas (H)/ Distilled Mustard (HD) 

 505-60-

2 

organic sulfur

compounds liquid 159.08 C4H8Cl2S 

423 oF

(217 oC)

57 oF 

 (14 oC) NA 

Mustard (HT) 

 172672-

28-5 

organic sulfur

compounds liquid 263.3 (T) 

C8H16Cl2S2O 

(T) 

> 228 

oC NA 0.0 - 1.3 oC 

Ethyldichloroarsine (ED) 

 598-14-

1 

halogenated, 

aliphatic liquid 174.89 C2H5AsCl2 NA < -65 oC NA 

 Lewisite (1) 

 541-25-

3 

halogenated, 

aliphatic liquid 207.31 C2H2AsCl3

159.8 

oC

32.2 oF 

(0.1 oC) NA 

 Lewisite (2) 

 40334-

69-8 

halogenated, 

aliphatic liquid 233.36 C4H4AsCl3 230 oC NA NA 

 Lewisite (3) 

 40334-

70-1 

halogenated, 

aliphatic liquid 259.39 C6H6AsCl3

215.4 

oC NA NA 

NA = Not Available 
21

Table 4. Physical/Chemical Properties of CWAs – Nerve Agents 

Compounds CAS # Chemical Class 

Physical 

State 

Molecular 

Weight 

Molecular 

Formula 

Boiling 

Point 

Freezing 

Point 

Melting 

Point 

 Sarin (GB) 

 107-

44-8 

esters, halogens, 

phosphine liquid 140.11 C4H10FO2P 

297 oF

(147 oC)

-71 oF (-

57 oC) NA 

 Soman (GD) 

 96-64-

0 

esters, halogens, 

phosphine, 

organophosphorus liquid 182.19 C7H16FO2P 

333 oF

(167 oC)

-94 oF (-

70 oC) NA 

Cyclohexyl sarin (GF) 

329-99-

7 

 esters, halogens, 

phosphine liquid 180.16 C7H14FO2P 228 oC 

-30 to -

50 oC NA 

 Tabun (GA) 

 77-81-

6 

organophosphorus, 

phosphoryls, 

amides liquid 162.13 C5H11N2O2P 248 oC 

-51 oF (-

46 oC) NA 

 VX 

 50782-

69-9 

phosphono, sulfur 

compounds liquid 267.36 C11H26NO2PS

568 oF

(298 oC)

< -60 oF 

(< -51 

oC) NA 

NA = Not Available 
22

Table 5. Physical/Chemical Properties of CWA Precursors and Degradation Products 

Compounds CAS # Chemical Class 

Physical 

State 

Molecular 

Weight 

Molecular 

Formula 

Boiling 

Point 

Freezing 

Point 

Melting 

Point 

Dimethylphosphite 

 868-

85-9 

phosphoryls, esters, 

alkyl phosphite liquid 110.05 C2H6O3P+

336-342 

oF (169-

172 oC) NA NA 

1,4-Dithiane 

 505-

29-3 

heterocyclic, sulfur, 

hydrocarbons solid 120.24 C4H8S2

390-392 

oF (199-

200 oC) NA 

226-235 oF

(108-113 

oC) 

 Thiodiglycol

 111-

48-8 

hydroxyls, 

aliphatic, 

mercaptans liquid 122.18 C4H10O2S 

541 oF

(283 oC)

3 oF (-16 

oC) NA 

 1,4-Thioxane

 15980-

15-1 

ethers, alicyclic, 

sulfur compounds, 

ethers liquid 104.17 C4H8OS 

297 oF

(147 oC)

1 oF 

 (-17 oC) NA 

 Trimethyl phosphite 

 121-

45-9 

organic, alkyl

phosphites liquid 124.09 C3H9O3P 

232-234 

oF (111-

112 oC) 

-108 oF 

(-78 oC) NA 

NA = Not Available 
23

Table 6. Physical/Chemical Properties of OP Pesticides and Other Pesticides 

Compounds CAS # Chemical Class 

Physical 

State 

Molecular 

Weight 

Molecular 

Formula 

Boiling 

Point 

Freezing 

Point 

Melting 

Point 

Chloropicrin 

 76-06-

2 

nitro, halogenated, 

aliphatic liquid 164.38 CCl3NO2

234 F 

(112 oC)

-83 oF 

 (-64 oC) NA 

Dichlorvos 

 62-73-

7 

heterocyclic, 

organophosphorous liquid 220.98 C4H7Cl2O4P 

183 F 

(84 oC) 

@1 

mmHg NA NA 

Dicrotophos 

 141-

66-2 organophosphorus liquid 237.21 C8H16NO5P 

266 oF

(130 oC) 

@ 0.1 

mmHg NA NA 

 Fenamiphos 

 22224-

92-6 organophosphorus solid 303.39 C13H22NO3PS NA NA 

120 oF

(49 oC) 

Methylparathion 

 298-

00-0 organophosphorus solid 263.22 C8H10NO5PS

228 oF

(109 oC) 

@ 0.05 

mmHg NA 

97 oF (36 

oC)
24

Table 6. (continued) 

Compounds CAS # Chemical Class 

Physical 

State 

Molecular 

Weight 

Molecular 

Formula 

Boiling 

Point 

Freezing 

Point 

Melting 

Point 

 Mevinphos 

 7786-

34-7 organophosphorus liquid 224.16 C7H13O6P 

617 oF 

(325 oC) 

-69 oF (-

56 oC) NA

 Phorate 

 298-

02-2 organophosphorus liquid 260.39 C7H17O2PS3

244-248 

oF (118-

120 oC) 

@ 0.8 

mmHg 

<5 oF (< -

15 oC) NA

 Tetraethylpyrophosphate 

 107-

49-3 organophosphorus liquid 290.22 C8H20O7P2 255 oF NA NA 

NA = Not Available 
25

Table 7. Physical/Chemical Properties of Rodenticides and Controlled Substances 

Compounds CAS # Chemical Class 

Physical 

State 

Molecular 

Weight 

Molecular 

Formula 

Boiling 

Point 

Freezing 

Point 

Melting 

Point 

284-297 

oF (140-

147 oC) 

 535- @ 4 189 oF 

Crimidine 89-7 pyrimidines solid 171.63 C7H10ClN3 mmHg NA (87 oC) Methyl 453- 104.5 fluoroacetate 18-9 ester, acetic acid NA 92.07 C3H5FO2 oC NA -35 oC  Nicotine from 54-11- nicotine sulfate 5 pyridinyl liquid 162.23 C20H30N4O4S 247 oC NA -79 oC 

275-279 

oF (135-

137 oC) 

77-10- @ 1 115-117 oF

 Phencyclidine 1 heterocyclic solid 243.39 C17H25N mmHg NA (46-47 oC) 

547-550 

 57-24- heterocyclic, oF(286-288 

 Strychnine 9 nitrogen, alkaloids solid 334.42 C21H22N2O2 NA NA oC) 

NA = Not Available 
26

The nerve agents (G-series and VX compounds, see Table 4) have a high acute toxicity and 

inhibit acetylcholinesterase throughout the body, disrupting the nervous system. They are 

structurally similar OP compounds and, thus, are quite similar to OP pesticides. However, the 

nerve agents contain a C-P bond that is not found in OP pesticides and that bond is very resistant 

to hydrolysis (1). The nerve agents differ somewhat in the remainder of their structure. VX 

contains sulfur while GB, GF, and GD contain fluorine; GA has a cyanide group. The G-series 

nerve agents are more volatile than VX and present a vapor hazard. Furthermore, GA, GB, and 

GF are more miscible in water, while VX and GD are less soluble (1). As Table 4 indicates, 

hydrolysis rates also differ amongst the nerve agents, with VX having the longest half-life (17 to 

42 days at 25 oC, pH 7). Though the C-P bond in nerve agents may resist hydrolysis, the overall 

hydrolysis half-lives for these compounds is much shorter than those for the OP pesticides 

discussed in this report (see Table 6). The P-F bond is the first to hydrolyze for GB, GD, and 

GF; the P-CN bond for GA; and the P-S bond is prone to hydrolysis for VX. Two of the 

compounds from Table 1 are precursors to the manufacturing of G-series nerve agents. These 

are trimethyl phosphite (TMP) and dimethyl phosphite, both of which are alkyl phosphites (see 

Table 5). TMP can also be used as an intermediate in the manufacturing of OP pesticides. 

The degradation of mustard agents can produce multiple compounds. Table 5 provides 

information on the degradation and hydrolysis products from the list of compounds of concern. 

1,4-Thioxane is a degradation product of mustard gas; 1,4-dithiane is a thermal degradation 

product of HD (1). Thiodiglycol is also known to be a product of the hydrolysis of HD. This 

chemical, though, is also a precursor to the production of sulfur-based blister agents. 

These degradation products are only a small portion of the overall number of degradation 

products associated with the CWAs identified in this report. Not only do CWAs break down in 

the environment, but the agents themselves are full of impurities which can also make their way 

into the environment in the event of a CWA distribution. In fact, the sulfur mustard agents alone 

(H, HD, and HT) have over 40 associated degradation products, hydrolysis products, and 

impurities (1). Lewisite has seven reported impurities and degradation products, while GA has 

22, GB has nine, and GD has seven reported impurities and degradation products; VX alone has 

over 30 (1). A table of the known toxic and persistent degradation products of the 

aforementioned CWAs can be found in Munro et al. (1). 

Dichlorovos, dicrotophos, fenamiphos, methyl parathion, mevinphos, phorate, and tetraethyl 

pyrophosphate (TEPP) are all OP pesticides (see Table 6). OP pesticides work similarly to the 

CWA nerve agents, inhibiting acetylcholinesterase in the insects they target. They can also act 

as acetylcholinesterase inhibitors in humans. OP pesticides are used on many fruit and vegetable 

crops as well as in and around buildings, though their residential uses have been voluntarily 

withdrawn by the manufacturers. Most OP pesticides are only slightly soluble in water, have a 

low volatility, and undergo hydrolysis. However, there are some exceptions to the rule. For 

example, dicrotophos is considered miscible in water but does not undergo hydrolysis quickly. 

Dichlorovos, on the other hand, is not as soluble but can hydrolyze rather quickly under the right 

conditions. Mevinphos and TEPP are also soluble in water, but their hydrolysis rates in neutral 

water differ greatly. For mevinphos, the half-life in water can be up to 35 days. The hydrolysis 

half-life for TEPP in neutral waters is closer to seven hours, with that time decreasing down to 

minutes as the pH increases. Phorate and methyl parathion have similar solubility in water as 
27

well as similar hydrolysis rates. Fenamiphos is more soluble than these OP pesticides, and its 

hydrolysis rate is also much quicker. 

Though the basic structural building block is consistent in all of the OP pesticides, each 

compound has a slightly different overall structure that separates it from the rest. As the name 

implies, dichlorovos has two chlorine atoms, while phorate has three sulfur atoms. Both methyl 

parathion and fenamiphos have a benzene ring, a sulfur atom, and a nitrogen atom, but they are 

not oriented in the same way. Dicrotophos has a nitrogen atom along with multiple methyl 

groups, while mevinphos has oxygen atoms with methyl groups. TEPP is set apart from all of 

the other OP pesticides by having two phosphorous atoms in its structure. These structural 

differences allow for the physical property differences discussed previously. 

The remaining compounds from the list are somewhat diverse. Chloropicrin is a pesticide (see 

Table 5) and is used as an insecticidal fumigant. It is also blended with several other toxic 

fumigants for insect control, but also has roots as a chemical weapon in World War I, where it 

was known as PS. Chloropicrin has also been described as an irritant and something that has 

been used for riot control as a tear gas. As with ED, chloropicrin is aliphatic and halogenated, 

but it contains nitrogen instead of arsenic. As with many other compounds in Tables 3 through 

7, this contaminant is not very water soluble. Crimidine and strychnine are both rodenticides 

(see Table 7) that act on cells in the brain and spinal cord to cause convulsions. Strychnine, 

however, is a very large molecule compared to crimidine, and is even less water soluble, though 

both are barely soluble. Nicotine (see Table 7) is a nerve poison that acts on the nicotinic 

acetylcholine receptors. Nicotine sulfate is an insecticide and nicotine can be generated from it. 

Nicotine shares one similarity with crimidine as well as phencyclidine (PCP) in that they all have 

nitrogen rings in their structure. Nicotine is also considered a drug, as is PCP. PCP (see Table 

7) is a dissociative drug and is also a neurotoxin. Both compounds are readily soluble in water, 

as some of the compounds previously discussed are. As with the other compounds, methyl 

fluoroacetate (see Table 7) is considered a toxin; it has rodenticidal properties. Fluoroacetates, in 

fact, were considered as potential CWAs at one point. As with some of the nerve agents, the 

hydrolysis half life for methyl fluoroacetate is quite long (2.5 percent in 60 hours). 

4.2 Summary 

A good understanding of the properties of each of the compounds of interest is important in 

selecting an appropriate wipe sampling method for them. As such, Tables 3 through 7 provide a 

synopsis of the physical and chemical properties of the compounds listed in Table 1. The CWA 

blister agents are presented in Table 3, CWA nerve agents in Table 4, CWA precursors and 

degradation products in Table 5, OP and other pesticides in Table 6, and the remaining 

compounds (rodenticides and controlled substances) in Table 7. Within each compound class, 

similarities and differences exist, as noted in this chapter. Many of the descriptions in this 

chapter reference the chemical structure of each compound to elucidate a better understanding of 

the compound classes. The chemical structures of each of the compounds listed in Table 1 can 

be found in Appendix A. 
28
29

Chapter 5 

Wipe Sampling Methods for Chemical Warfare Agents and Toxic Industrial 

Chemicals 

A variety wipe sampling techniques have been used for some of the compounds listed in Table 1. 

A summary of the wipe sampling information for the compounds of interest is provided in Table 

8. Information regarding the analyte, wipe material, wetting solvent, wipe surface, and 

determinative step are provided, including the reference where this information was obtained. 

Information gaps are designated as “NA” in the table, and as shown in Table 8, limited specific 

wipe sampling information was found for many of the compounds of interest. The literature 

information which was available and summarized in Table 8 is described in this section, 

organized by chemical class. 

5.1 OP Pesticides/Pesticides 

Surface wipe sampling for methyl parathion was conducted in a number of different studies. In a 

study of 18 pesticides (including methyl parathion) by Lemley et al. (32), living room dust wipe 

samples were taken, usually from a window sill or table, using two Whatman filter papers. One 

wipe was moistened with water and the other with aqueous methanol solution. Approximately 

0.031 m2

 was sampled by wiping across the area with each wipe. Methyl parathion was found in 

one of the 15 wipe samples taken. 

In a study by Clark et al. (33), methyl parathion wipe samples were collected to assess the 

potential exposures and health risks of a population, provide a basis for enforcement action, and 

determine which properties needed decontamination. Wipes consisted of gauze pads wetted with 

IPA. A 100 cm2

 area was wiped in this study. Surface sampled included baseboards, counter 

splashboards, and under the kitchen sink. Similar wipe sampling methods were used by Wasley 

et al. (34) for methyl parathion sampling in another study. Specific wipe sampling information 

was not found for the remaining OP pesticides (dichlorovos, dicrotophos, fenamiphos, 

mevinphos, and phorate). 

Though chloropicrin is considered a pesticide (though not an OP pesticide), it is also listed as a 

Scheduled (Schedule 3) chemical by the Organisation for the Prohibition of Chemical Weapons’ 

(OPCW’s) Chemical Weapons Convention (www.opcw.org). Details on sampling methods for 

Scheduled chemicals are discussed in the next section. 
30

Table 8. Summary of Wipe Sampling Information Found in the Literature for the Compounds of Interest 

Compound 

Class Compound Wipe Material Wetting Solvent 

Wipe 

Surface 

Determinative 

Step 

Chloropicrin lint-free cotton DCM, methanol NA NA 

 Dichlorvos NA NA NA NA 

 Dicrotophos NA NA NA NA 

 Fenamiphos NA NA NA NA 

filter paper 

water or aqueous 

methanol 

Window sills 

or tables GC/MS 

Kitchen 

OP Pesticides/ 

Pesticides Methyl parathion (baseboards, backsplash, 

under sink), 

bathroom GC/MS or 

gauze pad IPA (baseboard) GC/FPD 

 Mevinphos NA NA NA NA 

 Phorate NA NA NA NA 

 Tetraethyl 

pyrophosphate NA NA NA NA 

acetone, IPA, painted 

Q-tip, cotton cloth, felt, ethyl acetate, metal, 

 Distilled Mustard 

(HD) 

filter paper DCM concrete GC/MS 

Woven polyester/cotton 

CWAs - Blister 

blend IPA NA GC/MS 

lint-free cotton DCM, methanol NA NA 

Agents Mustard Gas (H) lint-free cotton DCM, methanol NA NA 

 Mustard (HT) lint-free cotton DCM, methanol NA NA 

 Ethyldichloroarsine 

(ED) NA NA NA NA 

 Lewisite (1) 

Woven polyester/cotton 

blend IPA NA GC/MS 

lint-free cotton DCM, methanol NA NA 
31

Table 8. (continued) 

Compound 

Class Compound Wipe Material Wetting Solvent 

Wipe 

Surface 

Determinative 

Step 

Woven polyester/cotton 

CWAs - Blister Agents

 Lewisite (2) blend IPA NA GC/MS 

lint-free cotton DCM, methanol NA NA 

Woven polyester/cotton 

 Lewisite (3) blend IPA NA GC/MS 

lint-free cotton DCM, methanol NA NA 

acetone, IPA, painted 

Q-tip, cotton cloth, felt, ethyl acetate, metal, 

Sarin (GB) filter paper DCM concrete GC/MS 

Woven polyester/cotton 

CWAs – Nerve Agents 

blend IPA NA GC/MS 

 lint-free cotton DCM, methanol NA NA 

 Soman (GD) 

Woven polyester/cotton 

blend IPA NA GC/MS 

 lint-free cotton DCM, methanol NA NA 

Cyclosarin (GF) lint-free cotton DCM, methanol NA NA 

Woven polyester/cotton 

Tabun (GA) blend IPA NA GC/MS 

 lint-free cotton DCM, methanol NA NA 

Woven polyester/cotton 

 VX blend IPA NA GC/MS 

CWA Precursors and Degradation Products 

 1,4-Dithiane NA NA NA NA 

 Thiodiglycol lint-free cotton DCM, methanol NA NA 

 1,4-Thioxane NA NA NA NA 

 Trimethyl 

phosphite lint-free cotton DCM, methanol NA NA 

 Dimethyl

phosphite lint-free cotton DCM, methanol NA NA 
32

Table 8. (continued) 

Compound 

Class Compound Wipe Material Wetting Solvent 

Wipe 

Surface 

Determinative 

Step 

Rodenticides 

Crimidine NA NA NA NA 

Methyl

fluoroacetate NA NA NA NA 

 Strychnine NA NA NA NA 

nonupholstered 

Controlled Substances 0.1% ascorbic 

living room

and bedroom

furniture; 10 

 Nicotine NA acid cm x 10 cm GC/MS 

 Phencyclidine NA NA NA NA 

NA = Information not available in the literature DCM = dichloromethane IPA = isopropyl alcohol GC/MS = gas chromatography/mass spectrometryGC/FPD = gas chromatography/flame photometric detector 
33

5.2 CWAs, CWA Precursors, and CWA Degradation Products 

In a Norwegian study, different types of wipe samples for collecting HD and GB on solid 

surfaces were used after the chemical agents had been applied to the area (35). Q-tips, cotton 

cloth (10 cm2), felt (1.5 cm diameter), and filter paper (1.5 cm diameter) were used as the wipe 

media. Acetone, IPA, ethyl acetate, and DCM were used as the wetting solvent with each wipe 

media. Two surfaces were tested as part of this experiment: a painted metal surface with 

combined layers of epoxy, polyurethane, and alkyd paint (similar to a military vehicle) and a 

concrete surface (to simulate a building). An artery clamp was used to hold the cotton cloth 

during sampling while disposable pincers were used for the filter paper and felt. Wipe materials 

were wetted with one of the aforementioned solvents, and wipe samples were taken from the 

sampling surface at 5 minutes, 6 hours, and 24 hours after the CWA application. Wipe samples 

were also taken using dry wipe media. For surface samples contaminated with HD, ethyl 

acetate-wetted Q-tips had the highest recoveries from painted metal surfaces (between 50 percent 

and 60 percent). Cotton cloths, however, are recommended by the OPCW (36). Higher 

recoveries were seen for wet over dry wipes after six and 24 hours. Recoveries were less than 

0.5 percent for dry Q-tips after six hours and 0.003 percent after 24 hours. Recoveries for Q-tips 

wetted with ethyl acetate were between 2 percent and 6 percent after six hours and 0.05 percent 

after 24 hours. Other wetting solvents gave recovery rates similar to that of ethyl acetate. 

On concrete surfaces, ethyl acetate wetted wipes gave recoveries of < 6 percent after 5 minutes 

for both HD and GB. Recovery rates were even lower after 6 hours (< 1 percent for HD). There 

were no significant differences between Q-tip and cotton cloth wipe recovery rates for HD from 

concrete surfaces. The Q-tip, however, proved to be easier to use in the field. 

Overall, the Q-tip was viewed to be the best medium for sampling solid surfaces for HD and GB 

(35). Better recoveries were found with wetted versus dry wipes, and ethyl acetate was the 

solvent of choice. It was also discovered that an increase in the amount of time that transpires 

between the initial application of the CWA and the wipe sample leads to lower recoveries of the 

agent from the surface. Recovery rates for HD using a Q-tip wetted with ethyl acetate dropped 

from 44 percent after five minutes on a painted metal surface to 2.4 percent after six hours to 

0.05 percent after 24 hours. Thus, the condition of the solid surface as well as the length of time 

after a contamination would influence the ability to determine the presence of CWAs. 

Various other wipe sampling methods have been employed for CWAs. The U.S. and Finland 

Joint Document describes the use of wipe samples for GA, GB, GD, HD, VX, and Lewisite 

using a 3" x 3" portion of as well as full Texwipe Clean Cotton Wipes, which are a 

polyester/cotton blend (37). Further sampling details were not provided. In an extension of the 

U.S./Finnish study evaluating the method’s ability to extract all of the CWAs from one wipe, a 

9" x 9" TXTM 1020 polyester/cotton blend wipe was used (38). The wipe was moistened with 

IPA before spiking tests were performed. 

The OPCW provides guidance for inspectors in collecting on-site wipe samples for scheduled 

chemicals. Scheduled chemicals include HD, H, HT, Lewisite 1, Lewisite 2, Lewisite 3, GB, 

GD, GF, GA, thiodiglycol, trimethyl phosphite, dimethyl phosphite, and chloropicrin. OPCW 
34

indicates that a packaged wipe from the sample collection kit should be used for the wipe 

material (36). This is usually an adsorbent wipe made of lint-free cotton. Some of the wipes are 

wetted with 2 mL of DCM while other are wetted with 2 mL of methanol. To take a sample, a 

DCM-wetted wipe is held with tweezers or haemostats and rubbed with force in a circular 

motion over the surface of interest. As necessary, the procedure is repeated with a methanolwetted wipe. 

5.3 Rodenticides 

No wipe sampling information was found in the literature for crimidine, methyl fluoroacetate or 

strychnine. 

5.4 Controlled Substances 

Matt et al. (39) collected wipe samples for nicotine analysis from living room and bedroom (nonupholstered) furniture using pre-screened wipes. The wipes were soaked in 0.1 percent 

(weight/volume) ascorbic acid. A 100 cm2 area was sampled. No information was found for 

PCP. 

5.5 Summary 

Table 8 summarizes the wipe sampling methods found in the literature for the compounds of 

interest listed Table 1. Unfortunately, much of the information that was sought for this report 

was not found in the literature, as indicated by the large number of “NA” designations in the 

table. In these instances, “NA” indicates that a particular category of information was not found 

in the reference that is cited. In many cases, only the sampling method was presented in the 

paper, not the analytical techniques required to test a given sample. Furthermore, most of the 

cited articles did not specify a particular surface on which to perform the wipe sampling. While 

most wipe sampling is generally performed on smooth, hard, non-porous surfaces, samples are 

often taken from many other surface types, as discussed in Chapter 3. Not providing a sampling 

surface in the referenced documents in Table 8 most likely indicates that the robustness of a 

particular sampling method beyond general non-porous surface sampling has not been explored. 

Before these methods could be used on different or novel surface types, surface residue 

extraction efficiencies would have to be investigated. 
35

Chapter 6 

Summary and Data Gaps 

6.1 Summary of Available Wipe Sampling Information for Compounds of Interest 

Limited wipe sampling information was found in the literature for the compounds of interest 

presented in Table 1. This section summarizes the literature information that was found by 

compound class. Information found in the literature summarized in Chapter 5 is used to discuss 

reasonable extrapolations as to what types of wipe, wetting agents, and techniques might be 

appropriate for the compounds for which no literature information was found. A general 

discussion of the information found throughout the report is also presented. 

 

6.1.1 OP Pesticides 

As shown in Table 8, literature information was only available for chloropicrin and methyl 

parathion. The wipe materials used in these studies were lint-free cotton, filter paper, and gauze 

pads; the wetting solvents used were DCM, methanol, water, and IPA. Surfaces wiped were 

only noted for methyl parathion wipe samples; the surfaces wiped in those studies were smooth 

and non-porous. 

Specific wipe sampling information was not found for the remaining OP pesticides of interest to 

this study. However, multiple wipe sampling methods were discussed for chlorpyrifos in Section 

3.2. Chlorpyrifos is an OP pesticide. Thus, it would be expected that sampling methodologies 

for chlorpyrifos could also be applied to other OP pesticides. However, the literature does not 

provide a consensus on which wipe sampling method is appropriate for all OP pesticides. The 

chlorpyrifos sampling methods included the use PUF rollers and cotton gauze pads moistened 

with water, IPA, and isooctane. The use of a cotton gauze pad, wetted with IPA has been used by 

more than one study and is the current method supported in multiple EPA studies. 

6.1.2 CWAs, CWA Precursors, and CWA Degradation Products 

The literature on CWAs and their precursor and degradation products indicated that cotton or 

polyester/cotton blend wipes, as well as Q-tips, have been used for sampling these compounds. 

The wetting solvents included mostly IPA, DCM, and methanol; with the exception of one study 

for Sarin (GB) and Mustard (HD) which also used acetone, IPA and ethyl acetate. Water could 

not be used for CWA wipe samples due to rapid hydrolysis. The studies cited in Table 8 did not 

agree on what wipe materials and wetting agents were preferable for CWAs. Limited 

performance data were only available for one study that only focused on wipe sampling for HD 

and GB (35). 
36

Surfaces wiped were only noted in one study by Opstad et al. where painted metal and concrete 

were sampled. This study determined that an increase in the amount of time that transpires 

between the initial application of the CWA and the wipe sample leads to lower recoveries of the 

agent from the surface. This implies that the condition of the solid surface as well as the length 

of time after a contamination would influence the ability to determine the presence of CWAs. 

CWA nerve agents are also OP compounds and behave similarly to OP pesticides. This would 

seemingly indicate that wipe sampling methods for OP pesticides could be used for the nerve 

agents in Table 1. In fact, the joint U.S./Finnish method tested wetting the CWA sampling wipes 

with IPA, the same wipe solvent used in multiple EPA studies (e.g., CTEPP and CHEERS) and 

is recommended in the ASTM method (10). 

 

6.1.3 Rodenticides 

No information was found on wipe sampling for the two rodenticides on the target compound 

list. The ASTM method (10) for organic compounds, however, specifies using a gauze wetted 

with IPA, which could be appropriate for these compounds as well. 

6.1.4 Controlled Substances 

As described in Section 5.4, only literature on wipe sampling for nicotine was found: cotton 

gauze, wetted with 0.1 percent ascorbic acid. Non-upholstered furniture were sampled in the 

cited study. This technique works well for nicotine because of its basic properties. Since PCP is 

also considered a basic drug, this wipe sampling method could be appropriate for it, too. 

6.1.5 General Thoughts on Available Wipe Sampling Information 

The literature review of each compound class indicated that cotton wipes are most commonly 

used. Most hard surface collection techniques for chlorpyrifos (and other OP pesticides) involve 

the use of some type of gauze pad. The OPCW recommends the use of a cotton cloth for CWA 

wipe sampling. Cloth or gauze wipes are easily transported, readily wetted, and are convenient 

for sampling most surfaces. Wipe samples that use cloth or gauze can even be used on more 

uniquely shaped surface areas. Of course, surfaces such as cement could snag or tear such a 

wipe material. In these instances, filters, cotton swabs or Q-tips, found to be the best performers 

in a CWA residue study (35), might be better. However, the amount of area that a swab could 

cover might be problematic. As the ASTM method (11) alludes to, gauze pads have been found 

to contain high background concentrations of potential interferents, depending on what chemical 

is to be sampled. In such instances where there is an interference, the wipes must be pre-cleaned, 

removing the potential interferent, before any sampling can occur. This can be costly and timeconsuming. In this case, Q-tips or even filters might be better, alternative wipe media to avoid 

this issue. 

As Table 3 indicates, most of the target compounds are readily soluble in organic solvents. The 

use of water as a wetting agent would then not be desirable, if not for this reason then for the 

reason that it would cause many of these chemicals to hydrolyze, eliminating the parent 

compound and leaving behind the hydrolysis products. Alcohol can be used as a suitable solvent 

for many of the compounds, and IPA appears to have the potential to be a reasonable wiping 
37

solvent for most of the compounds of interest. Even for studies like CHEERS, the IPA wipe was 

intended not only for sampling of OP pesticides, but also for collecting PBDEs, other pesticides, 

pesticide metabolites, and perfluorinated compounds. The ASTM method also notes IPA’s 

utility in collecting other compounds besides OP pesticides. Thus, IPA might also be an 

appropriate solvent for many of the compounds used in Table 1. 

One issue of potential concern with IPA-wetted wipes is that heavily wetted wipes are thought to 

extract chemical residues from within the sampling surface, not just residues on top of the 

surface. However, when sampling for the chemicals in Table 1, particularly after an attack or 

decontamination effort, this sampling effect may not be a concern. 

IPA was chosen for many studies because of its low toxicity, familiarity to study participants, 

and ability to not disturb most furniture finishes, because it was to be used mainly around 

children in EPA studies and on or near people for other studies. If the compounds in Table 1 are 

to be sampled in a less sensitive environment, then stronger solvents could potentially be used. 

DCM and methanol are recommended by the OPCW for collecting residual CWAs on surfaces. 

Ethyl acetate was determined to be a good wipe wetting solvent for the collection of HD and GB 

from surfaces. This solvent has also proven robust for sampling pesticides and other organic 

contaminants in exposure assessments, but is not often used because it can mar furniture finishes. 

Ethyl acetate wipes can, however, be easier to extract than those containing IPA. Given its past 

performance and ability to work for CWA sampling, ethyl acetate could also be a good wipe 

wetting solvent for most of the compounds in Table 1. Other solvents, including acetone and 

DCM, were also found to work reasonably well. These solvents could likely be applied to wipes 

for other CWAs or pesticides from Table 1, especially if the toxicity of the solvent or the 

possible destruction of furniture finishes is not a concern. 

6.2 Gaps 

As described throughout this report, many gaps still exist in determining the best wipe sampling 

method for the compounds listed in Table 1. Specific wipe sampling information, such as the 

wipe material and wetting solvent, was not available for many of the compounds of interest. 

Furthermore, details on the precise wipe method used as well as the performance of the method 

were often lacking. Before a wipe sampling method can be used for these compounds, existing 

methods must be fully validated and the gaps that exist must be filled in. 

Besides wipe sampling information being missing for many of the compounds of interest (see 

Table 8), one of the largest data gaps that was found was information on the effects of various 

surfaces. Wipe samples could potentially be taken from a variety of surfaces. Limited 

information was obtained from the literature on what techniques or materials are best on different 

surfaces, or even if there are any surface characteristics (e.g., porous versus non-porous) that 

might affect or interact with the compounds of interest and affect what is available for collection 

by a wipe. Gauze pads can be used on most surfaces, and they have been used extensively in the 

past (and present) to sample multiple household surfaces, toys, furniture, carpet, and hands 

among others. As noted in Section 3.7, PUF roller samplers have been used for turf and carpet 

sampling. Most of the sampling methods that were obtained for the compounds in Table 1, 
38

however, do not explore the usefulness of that method on various surfaces. Wiping surfaces from 

a building decontamination effort would include a large array of different surfaces that would 

need to be sampled. Thus, it is important to understand how different surfaces might affect the 

wipe sampling process as well as potentially the compound being sampled. Along these lines, it 

is also important to also determine the extraction efficiency of the wipe sampling method to 

determine which is appropriate to use either for a given surface, a given compound, or a 

combination of the two. 

A complicating issue for collecting wipe samples for CWAs (mainly nerve agents and some OP 

pesticides) is the fact that these compounds can undergo hydrolysis and other environmental 

breakdown, leaving behind degradation products in place of the parent compound. The wipe 

sampling discussed in this report focused on the parent compound, not sampling for degradation 

products, which can also be toxic. Munro et al. (2) contains a literature review of chemical agent 

degradation products and impurities, which can be numerous for a given chemical agent. In this 

article, a list of known persistent or toxic degradation products for many of the CWAs is 

provided. Degradation products included in the list that are not part of the target list for this study 

include diisopropyl methylphosphonate, EA 2192 (S-2-diisopropylaminoethyl 

methylphosphonothionic acid), ethylmethyl phosphonic acid, isopropyl methylphosphonic acid, 

and methylphosphonic acid. These degradation products tend to be small molecules and are more 

polar than the parent compounds. It is possible, however, that the wiping method for the parent 

compounds could be applied for the degradation products (i.e., IPA would most likely be the 

appropriate solvent). Any efforts to implement a wipe sampling method for CWAs will need to 

consider the hydrolysis products and how they fit into the overall sampling and analysis scheme. 

Wipe sampling methods have varied across studies found for this report. Some of the methods 

rely on vertical and horizontal strokes, while others recommend “S” or “Z” patterns, while still 

others call for more or less wipes per area. Sampling specifics for the compounds in Table 1 are 

very sparse, if not non-existent. Sampling areas are provided in a couple of studies. For a wipe 

method to be used properly and provide dependable and repeatable results, specific sampling 

steps must be followed, including how many wipes will constitute a sample, how much solvent 

to apply to the wipe, what pattern the area should be wiped in, and the amount of area that should 

always be wiped. This review did not attempt to investigate sampling designs, or data quality 

objectives, as this was outside the scope of this study, but these are aspects that must also be 

considered when applying a wipe sampling method. 

6.3 Conclusions 

Based on the findings of this literature review, it is clear that there is not an overwhelming 

consensus on how to take a wipe sample for collecting CWAs, OP pesticides, and other TICs 

from surfaces. Different methods, media, and wetting solvents have been recommended and 

used by various groups and studies. Many of the compounds in Table 1 do not even have a 

specific wipe sampling methodology for their collection. If the goal is to establish a wipe 

sampling method (or methods) for the compounds discussed in this report, then the next steps in 

this process must be research to investigate and fill in the gaps in wipe sampling knowledge that 

exist, followed by method validation to optimize the methods. 
39

Chapter 7 

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A-1

APPENDIX A 

CHEMICAL STRUCTURES FOR THE COMPOUNDS OF 

INTEREST 
A-2

Dichlorovos Dicrotophos Dimethyl Phosphite Ethyldichlo1,4-Dithiane 1,4-Thioxane Chloropicrin Crimidine 
A-3

Methyl Fluoroacetate Methyl Parathion Mevinphos Mustard 

Distilled 

Fenamiphos Lewisite (2) Le

Lewisite (1) 
A-4

Mustard (HT) Nicotine Phencyclidine (PCP) Phorate Sarin (GB) Cyclohexyl sarin (GF) Soman (
A-5

Trimethyl phosphite VX 

Strychnine Tabun (GA) Tetraethyl pyrophosphate (TEPP) Th