drywall
laminate tile
wood
EPA/600/R-16/189 I September 2016
www.epa.gov/homeland-security-research
United States
Environmental Protection
Agency
Evaluation of Chemical Warfare Agent
Wipe Sampling Collection Efficiencies
on Porous, Permeable, or Uneven
Surfaces
coated glass
Office of Research and Development
Homeland Security Research Program
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EPA/600/R-16/189
September 2016
Evaluation of Chemical Warfare Agent Wipe
Sampling Collection Efficiencies on Porous,
Permeable, or Uneven Surfaces
Technical Report and Sampling, Extraction, and Analysis Procedure
United States Environmental Protection Agency
Cincinnati, OH 45268
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Disclaimer
The U.S. Environmental Protection Agency through its Office of Research and Development funded and
managed the research described here under contract DE-AC52-07NA27344 to U.S. Department of Energy
by Lawrence Livermore National Laboratory under Interagency Agreement #DW89922616-01-0. It has
been subjected to the Agency's review and has been approved for publication. Note that approval does not
signify that the contents necessarily reflect the views of the Agency. Mention of trade names, products, or
services does not convey official EPA approval, endorsement, or recommendation.
Questions concerning this document or its application should be addressed to:
Stuart Willison, Ph.D.
U.S. Environmental Protection Agency
National Homeland Security Research Center
26 W. Martin Luther King Drive, MS NG16
Cincinnati, OH 45268
513-569-7253
Willison.Stuart@epa.gov
or
Romy Campisano (EPA Project Officer)
U.S. Environmental Protection Agency
National Homeland Security Research Center
26 W. Martin Luther King Drive, MS NG16
Cincinnati, OH 45268
513-569-7016
Campisano.Romy@epa.gov
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Acknowledgements
We would like to acknowledge the following individuals and organization for their contributions towards
the development and/or review of this method.
United States Environmental Protection Agency (EPA)
Office of Research and Development, National Homeland Security Research Center
Stuart Willison
Romy Campisano
Lukas Oudejans
Office of Site Remediation and Restoration
Elise Jakabhazy
Office of Land and Emergency Management
Larry Kaelin
Lawrence Livermore National Laboratory (LLNL)
Forensic Science Center
95th Civil Support Team (CST), Weapons of Mass Destruction (WMD), Hayward, CA.
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Executive Summary
Despite the fact that wipe sampling is commonly performed and the data produced by this technique
is used to make numerous decisions, there is no strong consensus on the best method for collecting a wipe
sample(s). It is generally agreed upon that in order to produce reproducible quantitative results, consistent
wetting solvents, wipe materials, sampling techniques, and sampling areas must be used. Furthermore,
proper wetting solvents should be selected with consideration of the analyte of interest. Conventional
practices dictate that wet wipes are better than dry wipes for the collection of organic chemicals. This study
was designed to understand factors affecting wipe sampling for specific chemical warfare agents (CWAs),
including sarin (GB), soman (GD), cyclosarin (GF), sulfur mustard (HD), and <9-cthvl-Y-(2-
diisopropylaminoethyl) methylphosphonothioate (VX) from non-ideal (e.g., porous and permeable)
surfaces, including drywall, vinyl tile, laminate, coated glass, and wood. Pesticides, diazinon (DZN) and
malathion (MA), were tested in addition to CWAs because literature data already exists and a comparison
is possible between previous work and the experimental investigations described in this report.
The experimental strategy for this study is considered follow-on work stemming from previous
collected data. The previous work identified Kendall-Curity® gauze as a preferred wipe when sampling for
CWAs based on holding time stability studies and the absence/low levels of contaminants/interferences
present in the wipe material. However, additional commercially available wipe materials will need to be
tested. Therefore, a Dukal™ gauze wipe was tested to investigate potential contaminants that might interfere
with CWA detection and a two-week long stability study was performed to determine the stability of CWA
spiked onto the Dukal™ wipe when stored under refrigerated conditions (2-4 °C). Experiments were
performed with coupon surface areas of either 10 cm2 or 100 cm2. The 10-cm2 coupons were of a size that
could easily be extracted in a 2-ounce jar (to provide comparative data for CWA recoveries generated by
direct extraction) and the 100-cm2 coupons better represented the area of a surface that might typically be
sampled by wipe extraction. In addition, CWA, at a normalized surface concentration of 0.1 |_ig per cm2
surface area, were spiked on coupons of the tested surfaces. Wipes were wetted with either dichloromethane
(DCM) or isopropanol (IPA) before sampling for CWA. The effects of wipe type, coupon surface area,
and solvent used to wet the wipe (i.e., wetting solvent) were tested. The utility of VX-dw as an extracted
internal standard was also tested.
Although different wipe wetting solvents were investigated, dichloromethane was used as the only
extraction solvent for both the Kendall-Curity® and Dukal™ wipes. Both wipe materials were found to have
similar alkane and phthalate contaminants, at fairly comparable concentrations. Thus, both the Kendall-
Curity® and Dukal™ wipes were recommended to be cleaned prior to use, if possible, by solvent extraction.
CWA spiked on the Dukal™ wipes, at tested concentrations of 0.1 (.ig and 1 jag, were stable on wipes stored
under refrigeration, except for VX. The Dunnett's Test showed that VX concentrations measured at Day
14 were statistically significantly lower than those measured at Day 0 (e.g., only 53% of the VX spiked at
1 |ag was recovered).
Recoveries for CWA and the pesticides from the surfaces of painted drywall, vinyl tile, laminate,
coated glass, and wood were analyte-dependent, matrix-dependent, and highly variable, as might be
expected when working with porous/permeable surfaces. Average recoveries (n = 3) of GB, GD, HD, GF,
VX, diazinon, and malathion from large (100 cm2 surface area, spiked with 10 (ig each analyte) and small
iv
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(10 cm2 surface area, spiked with 1 (.ig each analyte) coupons were determined under various extraction
conditions. Wipe sampling experiments were performed with Kendall-Curity® and Dukal™ wipes using
DCM or IPA as the wetting solvent. ANOVA was used to test for statistically significant differences in the
average recoveries. The tables presented in the report contain recovery efficiencies for the target CWAs
using both wipe types on each tested surface and direct extraction. Other factors that were tested in this
investigation (e.g., wetting solvent) and statistical analyses for each surface type are presented. Based on
the data within the tables, the findings are summarized below and should be viewed as general statements
for porous/permeable surfaces as the trend may not apply to all tested analytes and/or matrices.
• Painted drywall matrix
o In general, analyte recoveries by wipe sampling were < 50%
o Coupon size may affect analyte recoveries (in general, use of the small coupon
yielded greater analyte recoveries)
• Vinyl tile
o Analyte recoveries were highly variable
o Coupon size, wipe type, and wetting solvent may affect analyte recoveries
o Wipe type, wetting solvent, and coupon size may affect analyte recovery
• Laminate
o The more volatile CWAs (GB, GD, HD, and GF) were unable to be recovered from
the surface
o VX, malathion, and diazinon recoveries were typically > 30%
o Coupon size, wipe type, and wetting solvent may not affect VX, malathion, and
diazinon recoveries
• Coated glass
o GB and GD were unable to be recovered from the surface
o HD and GF recoveries ranged between non-detect (ND) to ~ 20%
o VX, malathion, and diazinon recoveries were typically > 50%
o Coupon size may affect GF, VX, malathion, and diazinon recoveries
• Wood
o Recoveries of target analytes from wood were consistently lower than other
matrices; GB, GD, HD, and GF were unable to be recovered by wipe sampling
o VX was only detected on the small coupon when IPA was used as a wetting solvent
o Malathion and diazinon were only detected when the Kendall-Curity® wipe was
used to sample the small coupon and recoveries were <45%
o ANOVA tests could not be performed for any of the analytes due to the high
number of non-detects (or the low number of detectable recoveries)
The following experiments performed in this study suggest that there was no clear "universal
wetting solvent" when sampling the tested surfaces. Recoveries with the Kendall-Curity® wipes appeared
to be higher than those observed with the Dukal™ wipes. Presumably, this was due to the larger size of the
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Kendall-Curity® wipes (3" x 3", versus the 2" x 2" size of the Dukal™ wipe) and the fact that the Kendall-
Curity® wipe had the ability to hold more solvent (5 mL, versus the 1.5 mL held by the Dukal™ wipe).
Further investigation is needed to compare wipes of similar size, ply, and wetting solvent volumes to
confirm whether a specific wipe type is preferred or if material characteristics are a determining factor for
analyte recoveries. Analyte recoveries could also be affected by coupon size. There are many factors
(material type, wipe type, wetting solvent, wetting solvent volume, etc.) that can affect analyte recovery
from porous/permeable surfaces and further investigation is needed to determine if surface area, or a
combination of any of the factors listed above, play a significant role with respect to recovery efficiencies.
CWA and pesticide recoveries by direct extraction and by wipe sampling of the small coupons were
compared using ANOVA. Direct extraction yielded statistically-significant, higher CWA recoveries than
wipe sampling for the removal of GB from painted drywall, GD from vinyl tile, GF from painted drywall,
HD from painted drywall and vinyl tile, VX, from vinyl tile and coated glass, malathion from painted
drywall and vinyl tile, and diazinon from painted drywall and vinyl tile. Direct extraction results suggest
that wipe sampling might underestimate CWA concentrations on/in these matrices. Wipe sampling most
likely will only account for analyte on the surface and not necessarily from within a porous/permeable
material. Thus, care must be taken when wipe sampling is performed and when interpreting results produced
from wipe sampling. The resulting implication is that a "non-detect" produced by wipe sampling cannot be
equated with the lack of CWA in a material.
Isotopically-labelled VX (VX- du) was used as an extracted internal standard to improve the
accuracy of VX recovery from the tested surfaces. In almost all cases, measured VX recoveries considering
VX- di4 responses were closer to expected recovery values (i.e., closer to 100 % recovery) than samples
that did not use this extracted internal standard. The use of VX- di4 allowed for a more accurate estimation
of VX concentrations when signals were low either due to background noise and/or matrix interferents.
Data suggest that the use of labelled extracted internal standards for all contaminants of interest are desirable
in future work when dealing with porous/permeable surfaces.
vi
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Table of Contents
Acknowledgements iii
Executive Summary iv
List of Tables viii
List of Figures ix
Abbreviations/Acronyms x
1.0 Introduction 1
2.0 Study Objectives 4
3.0 Experimental Conditions and Procedures 5
• 3.1 Materials 5
• 3.2 Extraction of Alternate Wipe Materials for Possible Interferences 8
• 3.3 Cleaning of Wipes 8
• 3.4 Spiking of Coupons and Wipes 8
• 3.5 Wipe Sampling Procedure for Tested Surfaces 8
• 3.6 Extraction of Wipe Materials for the Detection of CWAs 9
• 3.7 Analysis of Wipe Extracts 9
• 3.8 Holding Time Studies 9
• 3.9 Statistical Analyses 10
4.0 Results and Discussion 10
• 4.1 Evaluation of Dukal™ Wipe Contaminants 10
• 4.2 Surface Sampling with Different Wipes and Wetting Solvents 14
• 4.3 Recoveries from Direct Extraction versus Wipe Sampling 22
• 4.4 Sample Holding Times for CWAs on Dukal™ Wipes 24
• 4.5 VX-di4 as an Extracted Internal Standard 27
5.0 Conclusions and Recommendations 29
6.0 References 31
Appendix A: Sample Preparation and Analysis Method A-l
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List of Tables
Table 1. Wipe Contaminants Tentatively Identified by GC/MS; Peaks Numbers Correspond to
Those Listed in Figure 3 12
Table 2. Average51 Recoveries (%) for CWA, Pesticides(Shaded), and Surrogates from Painted
Drywall 15
Table 3. Statistical Analyses (ANOVA p-values) of CWA and Pesticide Recoveries (Table 2)
from Drywall 15
Table 4. Average51 Recoveries (%) for CWA, Pesticides, and Surrogates from Vinyl Tile 18
Table 5. Statistical Analyses (ANOVA p-values) of CWA and Pesticide Recoveries (Table 4)
from Vinyl Tile 18
Table 6. Average51 Recoveries (%) for CWA, Pesticides, and Surrogates from Laminate 19
Table 7. Statistical Analyses (ANOVA p-values) of CWA and Pesticide Recoveries (Table 6)
from Laminate 19
Table 8. Average51 Recoveries (%) for CWA, Pesticides, and Surrogates from Coated Glass.... 21
Table 9. Statistical Analyses (ANOVA p-values) of CWA and Pesticide Recoveries (Table 8)
from Coated Glass 21
Table 10. Average51 Recoveries (%) for CWA, Pesticides, and Surrogates'3 from Wood 22
Table 11. Statistical Analyses (ANOVA p-values) of CWA and Pesticide Recoveries from
Direct Extraction and Wipe Extraction (Small Coupons Only) 24
Table 12. Holding Time Study Data, 1 |ig Each CWA on Wipes 26
Table 13. Statistical Analysis of Holding Time Study Data, 1 |ig Each CWA on Dukal™ Wipes
26
Table 14. Holding Time Study Data, 0.1 |ig Each CWA on Wipes 27
Table 15. Statistical Analysis of Holding Time Study Data, 0.1 |ig Each CWA on Dukal™ Wipes
27
Table 16. Average51 Recoveries (%) for VX, from Various Matrices, With and Without
Consideration of VX-di4 Extracted Internal Standard (Listed as VX by IS) 28
viii
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List of Figures
Figure 1. Kendall-Curity® wipe (left) and Dukal™ wipe (right) 5
Figure 2. Materials tested in this study (100 cm2 and 10 cm2 coupons) 7
Figure 3. TICs for wipes that were received, extracted, and analyzed by GC/MS. Compounds
were tentatively identified by library search and summarized in Table 1 11
Figure 4. TICs for method blank and Dukal wipes pre-cleaned and "as received" 13
Figure 5. TICs for method blank and Kendall-Curity wipes pre-cleaned and "as received" 13
IX
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Abbreviations/Acronyms
2-FB
2-fluorobiphenyl
ANOVA
Analysis of Variance (statistical analysis technique)
CCV
Continuing calibration verification
CWA
Chemical Warfare Agent
DCM
Dichloromethane
DZN
Diazinon
EPA
United States Environmental Protection Agency
GB
Sarin
GC
Gas Chromatograph
GC/MS
Gas Chromatography/Mass Spectrometry
GD
Soman
GF
Cyclosarin
HD
Sulfur mustard (distilled)
IPA
Isopropanol
IS
Internal Standard
KC
Kendall Curity® gauze wipe
LLNL
Lawrence Livermore National Laboratory
MA
malathion
MS
mass spectrometer
NB-ds
Nitrobenzene-ds
ND
non-detect
NIST
National Institute of Standards and Technology
NMR
Nuclear Magnetic Resonance Spectroscopy
OP
Organophosphorus pesticideoz Ounce
PFTBA
Perfluorotributylamine
P/N
part number
PTFE
polytetrafluoroethylene
ter-dw
Terphenyl-d-14
TIC
Total Ion Chromatogram
VOA
Volatile Organic Analysis
v/v
Volume/volume percent
VX
O-ethyl-,S'-(2-diisopropylaminoethyl) methylphosphonothioate
VX- di4
Deuterated <9-cthyl-S'-(2-diisopropylaminocthyl) methylphosphonothioate
X
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1.0 Introduction
Recovering from a chemical warfare agent (CWA) incident in an urban setting can present
a myriad of challenges when characterizing the site and determining the extent of contamination.
Contaminated areas within this setting can include materials of different morphologies and types,
such as walls, floors, and furniture. Although direct extraction may be the preferred process, it is
often not feasible when investigating these surfaces; thus, wipe sampling becomes the preferred
technique. Direct extraction and wipe sampling each have advantages and disadvantages. Wipe
sampling, as a collection technique, can be performed easily, rapidly, and without destruction of
the tested surface; however, wipe sampling might not remove as much analyte from a material as
direct extraction. For example, wipe sampling can only remove analyte from the surface of a
material and not from within a material, which can be problematic when sampling porous surfaces.
Direct extraction of a bulk material has the potential to remove analytes that have penetrated into
a material, but may also extract numerous interferents from the material as well resulting in the
potential for false positives or difficulty identifying target analytes. For this reason, it is important
to understand analyte recovery efficiencies when interpreting wipe sampling and direct extraction
data from bulk materials. Furthermore, it is important to understand the quantities of CWA that
might still be present in a material after wipe sampling and direct extraction procedures are
performed and the potential maximum recovery efficiencies from each technique.
Despite the fact that wipe sampling is commonly performed, and the data produced by this
technique can be used to make numerous decisions, a recent review of wipe sampling (1)
concluded that "there is not an overwhelming consensus on how to take a wipe sample for
collecting CWAs, organophosphorus pesticides, and other toxic industrial chemicals from
surfaces." In order to produce quantitative results, consistent wetting solvents, wipe materials,
sampling techniques, and sampling areas must be used. Earlier work by the U.S. Environmental
Protection Agency (EPA) found that "Experience and consistency of technique were determined
to play significant roles concerning the overall accuracy and precision, in obtaining surface
samples" (2). In addition, that same study concluded that: wetted wipes collected more analyte
than dry wipes; wetting solvents should be selected with consideration of the analyte of interest;
there was an apparent correlation between surface area of the wipe material and analyte recovery;
and that analyte recoveries depended, in part, on the porosity of a surface.
This investigation was a follow-on project from a previous study that examined wipe
sampling on non-porous surfaces contaminated with CWAs (3, 4). The interpretation of CWA
wipe efficiency results was complicated because of the compounding effects of analyte
volatilization and degradation. CWA wipe sampling from the previous investigation included a
stainless steel and glass surface. Each surface was tested with several different wipe materials,
including cotton gauzes (one from Kendall-Curity® and one from Certified Safety®), a glass fiber
filter, and a cellulose fiber filter. The investigated wetting solvents included DCM, 50/50 (v/v)
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acetone/DCM, hexane, and IP A. The previous study focused on wipe sampling of non-
porous/impermeable surfaces, such as stainless steel and glass, because these surfaces are expected
to provide optimum analyte recoveries, thus, a best case scenario for recovering the analyte from
the surface. The current study, described herein, sought to expand the knowledge of CWA wipe
sampling from surfaces that are more difficult to sample because they are porous and/or permeable.
Findings from the previous work (3) influenced the direction of this investigation and were used
to implement some of the experimental parameters listed below:
Previous investigation concluded that the Kendall-Curity® gauze was a generally
acceptable material, because of its ability to be effectively pre-cleaned, its structural
integrity, and its ability to retain wetting solvent. Other commercially-available
wipes still need to be tested to ensure proper optimal wipes are available in addition
to the Kendall-Curity® gauze wipe. Therefore, another commercially-available
gauze wipe (Dukal™) was tested.
A clear "best solvent" for CWA sampling could not be identified from the previous
work. From an operational perspective; however, IPA was favored because it was
least prone to evaporation and not destructive to the tested surfaces. CWA analytes
are stable in DCM solvent; thus, IPA and DCM, were selected as wetting solvents
for the wipes. Both are expected to easily penetrate the surface of the tested
materials.
The previous study used small sampling surface area coupons of 10 cm2. The
current investigation used a larger surface area (100 cm2), which is a better
representation of a wipe sampling area used to collect analytes. For comparative
purposes, coupons having both 10 cm2 and 100 cm2 surface areas were tested.
Direct extraction was also used to compare wipe efficiency results.
Diazinon and malathion were included to investigate the behavior of these
pesticides as CWA surrogates. Literature data exists regarding the wipe sampling
of these chemicals for comparative purposes and these analytes were included in
the previous work.
The purpose of this study was to investigate recovery efficiencies from sampling of
porous/permeable surfaces by direct extraction and wipe sampling techniques. Specific CWAs,
including sarin (GB), soman (GD), cyclosarin (GF), sulfur mustard (HD), and (9-ethyl -S-(2-
diisopropylaminoethyl) methylphosphonothioate (VX), and the pesticides diazinon (DZN) and
malathion (MA) were tested. The tested surfaces evaluated in this study (painted drywall, vinyl
tile, laminate tile, coated glass, and wood) represent a wide range of materials (e.g., chemical
composition and properties, surface characteristics) that are commonly found in many urban
locations. Some of these materials might be expected to be left in place during a remediation
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process. Two different coupon sizes were used during the investigation (10- cm2 and 100- cm2).
The 10-cm2 coupons represent a size that could easily be extracted in a 2-oz jar (to provide
comparative data for CWA recovery efficiencies generated by direct extraction) and the 100-cm2
coupons represent the area of a surface that might typically be sampled by wipe extraction. Tests
were performed with 1 |ig of each CWA per small sample coupon and 10 jug of each CWA per
large sample coupon so that in each test, a consistent, normalized surface coverage of 0.1 |ig/cm2
of CWA was used. Specific combinations of wipes and wetting solvents were investigated to
determine an optimal extraction of CWAs from the various surfaces. An analysis of variance
(ANOVA) was performed to determine statistical differences in the measured recoveries. ANOVA
provides a statistical test of whether or not the means of several groups are equal or a statistical
significance exists between the measured groups.
To the extent possible, only questions involving analytical methods, and not those of
environmental persistence of CWAs (i.e., the persistence of the CWAs on the surfaces), were
examined. During the previous investigation, where CWAs were evaluated on surfaces (3), the
study did not indicate a preferred wetting solvent, so both dichloromethane (DCM) and
isopropanol (IPA) were evaluated. IPA was tested in addition to DCM because it was expected to
be less destructive to surfaces than DCM.
The Kendall-Curity® gauze wipe (KC) was previously tested and determined to be the preferred
wipe to use during CWA sampling activities (3); however, a similar wipe, Dukal™ gauze, was
evaluated during this investigation for comparative purposes and to simulate the use of
potentially multiple wipe types that might be used as part of the sampling process during an
incident. The cleanliness of the Dukal™ wipe was assessed and compared to that of the Kendall-
Curity® wipe. Additional testing of the Kendall-Curity® wipe was performed in parallel with
tests of the Dukal™ wipe to ensure that both extraction and analysis processes for each wipe was
performed under equivalent experimental conditions and that accurate comparisons between the
two wipe materials were possible. The wipes tested "as is" (i.e., as received, directly from their
packages) were extracted with DCM with the same procedure used to extract the wipe samples
from surfaces (see Appendix A). The "pre-cleaned" wipes were cleaned by Soxhlet extraction
with DCM for 10 cycles. GC/MS analyses were performed to determine the nature of
contaminants that were present in the Dukal™ wipes and to determine if cleaning of these wipes
was necessary prior to use for sample collection.
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2.0 Study Objectives
Previously-tested wipe sampling methods (on metal and glass) were used to determine
study objectives for CWA wipe collection efficiencies on the non-ideal (e.g., porous, permeable,
or uneven) surfaces (3). Tested (non-ideal) surfaces included vinyl tile, wood, laminate, coated
glass, and painted drywall. Objectives were designed to address the following questions listed
below. Answers to these questions will help define the usefulness (and limitations) of wipe
sampling versus direct sampling on non-ideal surfaces.
Are there contaminants and/or interferents found within alternate wipe materials (e.g.,
Dukal™ wipes) that could potentially interfere with targeted CWA analysis?
What is the stability of a CWA, spiked at 0.1 |ig and 1.0 |ig, on an alternate wipe
material (e.g., Dukal™ wipe)?
Do extraction efficiencies for Kendall-Curity® and Dukal™ gauze wipes differ when
tested on non-ideal surfaces and is there a preferred wipe material for CWA sampling?
Does a preferred wetting solvent exist for ideal or non-ideal surfaces (e.g., isopropanol
or dichloromethane)?
What is the effect (if any) from sampling a different surface area (e.g., 10-cm2 coupon
versus 100-cm2 coupon of similar material) and will the result yield equivalent or
different CWA recovery concentrations?
Are collection efficiencies of wipe sampling and direct extraction techniques
equivalent for coupons of the same surface area (e.g., 10 cm2 surface area)?
Does the use of a deuterated surrogate (e.g., VX-di4) as an extracted internal standard
(i.e., spiked prior to sample processing and analysis) provide better measurements for
VX recovery concentrations and is this information applicable to other CWAs?
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3.0 Experimental Conditions and Procedures
3.1 Materials
The following wipe materials were tested and are described below (Figure 1):
Kendall-Curl tv' cotton gauze wipes. 3 in. x 3 in., sterile, cotton gauze (Kendall-Curity,
12-ply, P/N 1903, Tyco ITeathcare Group LP, Mansfield, MA)
Dukal™ gauze wipes. 2 in. x 2 in., sterile gauze (sold by Fisher Scientific, Pittsburg,
PA, as North Co. by Honeywell, P/N 17986486; it should be noted that the wipe
received was a gauze wipe, 12-ply, made by Dukal Corp. Ronkonkoma, NY)
Game Sponges
GAUZE PAD
KenDALL
111*1*1)*
|(75cm*rsc*>
lAIOt
VWRScientific
vw" Products
Figure 1. Kendall-Curity® wipe (left) and Dukal " wipe (right).
5
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The following building materials were tested and are described below (Figure 2):
Painted drywall - Standard, V2" drywall was obtained as surplus from onsite Lawrence
Livermore National Laboratory (LLNL) facilities and are representative samples from
commercial hardware stores. Two coats of combination paint and primer (Ultra-Pure
White, Interior Matte, Behr Premium Plus Ultra, acrylic paint, P/N 175001, Behr Corp.,
Santa Ana, CA) were applied to the drywall.
Polymer-coated glass - Glass coupons were cut from commercial window glass by
Livermore Glass Company (Livermore, CA). Once cut, a coating (Prestige coating,
P/N PR-70, run number 3024324013, 3M, St. Paul, MN) was applied per
manufacturer's instructions (8). Dilute baby shampoo (Top Care by Topco Assoc. LLC,
Skokie, IL), a couple of drops added to a liter of tap water, in a spray bottle, was used
as a slip solution to position the coating. A squeegee tool was used to simultaneously
adhere the coating to the glass, to remove all air bubbles, and to remove excess slip
solution.
Wood - Surplus plywood was obtained from onsite LLNL facilities and are
representative samples from commercial hardware stores (top layer of solid wood is
3/32" thick).
Vinyl tile - White vinyl tile materials (1/8" thickness) were purchased from
commercial hardware stores and cut to appropriate size. (Excelon Sanddrift, P/N VCT
51858-45SF, Armstrong, Lancaster, PA).
Laminate (laminate countertop) - The white 3' x 8' sheet, was obtained from
commercial hardware stores and cut to appropriate size. (Designer White, P/N d354-
60), Wilsonart LLC, Temple, TX).
All materials were cut to coupon sizes of approximately 10 cm2 and 100 cm2. The smaller
coupon size was selected to allow the direct extraction of surface materials in 2-ounce (oz) jars.
Furthermore, a direct comparison is possible between direct solvent extraction of a surface and
wipe extraction of a coupon with the same surface area. The larger coupon size (100 cm2) was
selected to be comparable in size to a 10 cm x 10 cm surface area that might be sampled during an
environmental remediation.
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Solvents used for the wipe study included dichloromethane (DCM) (AMD Chromasolv®,
>99.8% for gas chromatography (GC), P/N 34897-6X1L, Sigma-Aldrich, St. Louis, MO) and
isopropanol (IPA) (anhydrous, 99.5%, P/N 278475-1L, Sigma-Aldrich, St. Louis, MO).
CWA analytes were synthesized at LLNL and spiked onto the various surfaces from a 10
ug/'inL solution in DCM. They included sarin (GB), soman (GD), cyclosarin (GF), sulfur mustard
(HD), and 0-ethyl-»Y-(2-diisopropylaminoethyl) methylphosphonothioate (VX). Spiking solutions
were made from neat agent in DCM. The purities of the neat agents were determined by nuclear
magnetic resonance (NMR) spectroscopy to be 95%, 95%, 95%, 99%, and 96% for GB, GD, GF,
HD, and VX, respectively. Malathion was obtained as a 100-ug/mL solution in cyclohexane (P/N
31558, Sigma Aldrich, St. Louis, MO). Diazinon, was obtained as a 100 ug/mL in acetonitrile
(part number 45842, Sigma Aldrich, St. Louis, MO).
drywall
laminate til
woo
Figure 2. Materials tested in this study (100 cm2 and 10 cm2 coupons).
7
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3.2 Extraction of Alternate Wipe Materials to Investigate Possible Interferences
with Target CWAs
A single Dukal™ wipe was extracted with DCM, using the method described in Appendix
A, §8, but without surrogate/internal standards. The resulting sample extract was reduced in
volume to 1.0 mL and analyzed by gas chromatography/mass spectrometry (GC/MS) to investigate
any potential contaminants or interferents that may be present in the native wipe materials prior to
use with CWAs and target surfaces (Appendix A). Potential interferents were tentatively identified
by comparison of their mass spectra to those contained in the NIST '08 Mass Spectral Database
and discussed in Section 4.1. Duplicate samples were analyzed to determine if interferences were
present in the Dukal™ wipe material.
3.3 Cleaning of Wipes
As suggested during the previous investigation (3), all wipes used for CWA analysis should
be pre-cleaned prior to use to reduce any interference with CWA signal intensities and analytical
capabilities. Because both wipes contained some interferents in the region where VX elutes (Table
1), all wipes used in this study were cleaned by Soxhlet extraction (10 cycles) with DCM as
prescribed. Further details are discussed in Section 4.1.
3.4 Spiking of Coupons and Wipes
Coupons were spiked with CWAs, malathion, and diazinon from a multi-component, dilute
solution (10 |ig/mL each component) in DCM (see Appendix A, §8, for details of spiking
procedure). The spiking solution standard was used within a day of preparation. Appropriate
volumes of the solution were deposited on the matrices of interest using calibrated pipettes
(Appendix A, §8). All 10-cm2 coupons were spiked with 1 |ig of each CWA and pesticide (spiked
with 100 |iL solution, deposited as five, 20-|iL drops, of the 10 ng/|iL stock solution). All 100-cm2
coupons were spiked with 10 ng of each CWA and pesticide (spiked with 1000 |iL solution,
deposited as fifty, 20-|iL drops, of the 10 ng/|iL stock solution). Both sizes of coupons were spiked
with the same normalized concentration of CWA (i.e., both size coupons were spiked with 0.1 |ig
CWA per square centimeter of surface area). The coupons were directly extracted or wiped as soon
as solvent evaporation was complete (~ 5 minutes) to minimize the possibility of CWA loss due
to evaporation or surface reactions as DCM will degrade surfaces (e.g., plastics).
3.5 Wipe Sampling Procedure for Tested Surfaces
A consistent, predetermined volume of solvent (Appendix A, 8.3) was used to wet each
wipe material so that the wipe was saturated, 5.0 mL for the Kendall Curity® gauze wipes and 1.5
mL for the Dukal™ gauze wipes. Surfaces were sampled by first using a horizontal "Z" shaped
pattern to wipe the entire surface of the coupon; then the wipe was folded inward so that the used
portion is concealed. Once folded inward, the newly exposed part of the same wipe was used to
sample the same surface in a vertical "Z" pattern. The coupons were held stationary during the
wiping operation with solvent-rinsed forceps. The wipe or coupon was immediately placed in a
8
-------
40-mL volatile organic analysis (VOA) vial and extracted with the appropriate amount of DCM
solvent volume (Section 3.6 and Appendix A, §8) to determine CWA removal from the surface.
3.6 Extraction of Wipe Materials for the Detection of CWAs
The extraction process is summarized below and described in detail in Appendix A. After
surface wiping was completed, the gauze wipe (or smaller coupon used for direct extraction) was
placed in a pre-cleaned, 40-mL, clear, glass vial with polytetrafluoroethylene (PTFE)-lined screw
cap. Surrogate solutions were added, in appropriate amounts (1 |ig each compound), directly onto
the wipe samples. All samples were extracted, twice, for 15 minutes each with 15 mL of DCM,
using a shaker table. Prior to analysis, the combined sample extracts were evaporated using a gentle
stream of clean, dry nitrogen (RapidVap unit and a Pierce Reacti-Therm™ III, with an evaporation
module) to just below 1 mL. The sample extract was adjusted to a final volume of 1.0 mL with
DCM and the appropriate amount of internal standard (to provide a concentration of 1.0 |ag/m L
for each internal standard compound - see Appendix A) was added prior to analysis.
Quality assurance and control samples and method blanks were included during the wipe
extraction process. All quality assurance and control samples are presented in Appendix A.
Method blanks did not contain CWA, but were extracted and treated in an identical manner to
wipes used to sample CWA. Control samples consisted of 1 |ig each CWA and pesticide, 1 |ig
each surrogate (see Appendix A, §7.0), and 1 |ig each internal standard (see Appendix A, §7.0)
spiked directly into 1.00 mL DCM.
3.7 Analysis of Wipe Extracts
Analysis conditions are briefly summarized below, but are described in greater detail in
Appendix A, §10. The GC/MS analyses were performed with an Agilent 5975C MS coupled with
an Agilent 7890 GC (both from Agilent Technologies, Inc., Santa Clara, CA). The GC/MS was
tuned and calibrated, as needed, with perfluorotributylamine (PFTBA), using the vendor's
algorithms and specifications. Prior to analysis of samples, a calibration curve in DCM was
analyzed, followed by the analysis of a CWA test mixture, equivalent to the continuing calibration
verification (CCV) standard, to establish that the GC/MS was functioning properly. Each batch of
samples was analyzed with a corresponding method blank and control samples (Section3.6 and
Appendix A). During the course of analysis, CCV standards, at 1 ng/|iL, were analyzed for each
analysis batch, which consisted of no more than twenty samples (Appendix A). The responses of
these standards must be within 20% of the response of the initial calibration in order for the
collected data between CCV checks to be considered valid. For GC/MS analyses, the surrogate
and internal standards were consistent with those of EPA Method 8270 (4).
3.8 Holding Time Studies
A holding time study was previously performed by spiking CWAs on the Kendall-Curity®
wipe (3). For comparison, experiments were conducted to determine the stability of CWAs spiked
on DCM-wetted (0.5 mL) Dukal™ wipes, at amounts of 1 |ig and 0.1 |ig. CWAs were spiked on
9
-------
the wetted wipes, stored in closed VOA vials in a refrigerator (2-4 °C), and analyzed on Days 0,
2, 7, and 14to determine the stability of the analytes.
3.9 Statistical Analyses
A program called "R" (5) was used to perform statistical analyses to determine whether
differences in measured CWA concentrations were statistically significant. Three statistical
parameters were examined. The Dunnett's method was used in analysis of variance (ANOVA) to
create confidence intervals for differences between the mean of each factor level and the mean of
a control group. The Dunnett's Test was used to determine if there was a statistically significant
decrease in CWA concentrations at various time points sampled during the holding time study.
Secondly, a three-way ANOVA was used to determine if wipe type, solvent type, and coupon size
significantly affected the concentrations of measured CWA. Finally, ANOVA was also used to
test if concentrations measured by direct extraction of the small coupons were statistically different
than those measured using wipe extraction of the small coupons.
4.0 Results and Discussion
4.1 Evaluation ofDukal™ Wipe Contaminants
The cleanliness of the Dukal™ wipe was assessed and compared to that of the previously-
investigated Kendall-Curity® wipe (3). Figure 3 represents the total ion chromatograms (TICs)
produced by analyzing the wipe extracts from both the Dukal™ and Kendall-Curity® wipes; the
tentative identities (i.e., determined by match with the NIST mass spectral library) of the numbered
peaks are presented in Table 1. Table 1 also contains the "reverse fit" value, which indicates how
well the recorded mass spectrum agreed with its best match in the NIST database (with a value of
1000 being a perfect fit). The "reverse fit" value is generated by comparing the spectrum of the
unknown and the library spectrum and ignoring any peaks in the unknown that are not in the library
spectrum. Both wipes contained similar alkane and phthalate contaminants.
Figures 4 and 5 indicate a reduction of contaminants for both the Kendall-Curity® and for the
Dukal™ wipes in the TIC region, the region in which VX, diazinon, and malathion elute, after
cleaning. For comparative purposes, under the GC/MS conditions described in Appendix A, GB,
GD, HD, GF, VX, diazinon, and malathion elute at retention times of approximately 6, 11, 13,
14, 22, 23, and 25 minutes, respectively. Thus, the TIC data suggest that both the Dukal™ and the
Kendall Curity® wipes should be cleaned, if possible, before use. This conclusion is in agreement
with that of the previous study, which also recommended that the Kendall-Curity® wipe be
cleaned before use (3). In the previous study, CWA recoveries for pre-cleaned and "used as
received" Kendall-Curity® gauze wipes were the same, with the exception that both VX and
malathion showed statistically significant higher recoveries from uncleaned gauze than from pre-
cleaned gauze. This, in part, was attributed to co-eluting interferences in the region of
approximately 20-25 minutes in the TIC.
10
-------
12
1 4e+08
Dukal wipe, not precleaned
1 23 4 5 6 78
11
9 10 |
L3
14
5.00
10.00
15.00
20.00
25.00
1.4e+08
Kendall Curity wipe, not precleaned
30.00 35.00
11
10
?§yHa_l*aJk(i
L
JUJL
5.00
10.00
17
1819
20
' 22
21 |
13
14
12 1516
1 -*
15.00 20.00 25.00
Retention Time (min)
30.00
35.00
Figure 3. TICs for wipes that were received, extracted, and analyzed by GC/MS. Compounds
were tentatively identified by library search and summarized in Table 1.
11
-------
Table 1. Wipe Contaminants Tentatively Identified by GC/MS; Peaks Numbers Correspond to
Those Listed in Figure 3
Peak
Tentative Identification
Retention Time (min)
Reverse Fit
1
2-(2-ethyoxyethyoxy)ethanol
10.39
967
2
2,4-di-tert-butylphenol
19.62
884
3
butylated hydroxytoluene
19.68
920
4
n-hexadecane
20.85
962
5
n-heptadecane
22.28
924
6
n-octadecane
23.63
943
7
n-hexadecanoic acid
25.73
930
8
n-eicosane
26.13
920
9
n-tricosane
29.50
909
10
n-tetracosane
30.53
959
11
n-pentacosane
31.54
907
12
di-n-octyl phthalate
32.09
856
13
n-hexacosane
32.50
909
14
n-heptacosane
33.41
890
15
n-octacosane
34.30
916
16
n-nonacosane
35.16
887
17
Surfynol 104
18.08
876
18
tributylphosphate
21.61
959
19
Uniplex 108
21.84
869
20
pentadecanal
22.51
915
21
dibutylphthalate
25.78
953
22
docosane
28.43
946
12
-------
2e+08
Method blank
3 2e+08
>*
03
_Q
<
Dukalwipe, precleaned
I. a 1. i.. I
. J J. ¦ I I I ¦ Mill. ¦ ¦ ¦
2e+08
Dukal wipe, as is
i_L.
5.00 10.00 15.00 20.00 25.00 30.00 35.00
Retention Time (min)
Figure 4. TICs for method blank and Dukal wipes pre-cleaned and "as received"
1.4e+08
00
+J
'c
3 1.4e+08
>
L_
n:
¦M
JD
<
1.4e+08
l i" i——L-
ii ri-. t,
La ,.
Method blank
Kendall-Curity wipe, precleaned
Kendall-Curity wipe, as is
i i JUUi
5.00 10.00 15.00 20.00 25.00 30.00 35.00
RetentionTime (min)
Figure 5. TICs for method blank and Kendall-Curity wipes pre-cleaned and "as received"
13
-------
4.2 Surface Sampling using Different Wipes and Wetting Solvents
CWAs were spiked onto various surfaces and their average (n = 3) recoveries were
determined for different wipes (Kendall-Curity® or Dukal™) and wetting solvents (IPA or DCM).
Wipe sampling of both small (10 cm2) and large (100 cm2) coupons was conducted for each of the
test materials. CWA and pesticide recoveries are organized by surface type and presented in Tables
2, 4, 6, 8, and 10. Comparison of CWA and pesticide recoveries obtained by direct extraction of
the small coupons and by wipe sampling will be discussed in Section 4.3. Wipe recoveries are
based on the analyte responses generated from calibration curve, unless noted.
Analysis of variance (ANOVA) was performed to determine statistical differences in the
measured recoveries. Non-detections were replaced with random values generated from the
uniform distribution ranging from zero to the detection limit when performing the statistical
analyses. Generated substitute values averaged one-half the detection limit when using this
approach. Overall, the values provided similar results to the existing method for substituting a
fixed, one-half the detection limit. While the substitution of one-half the detection limit for non-
detects is commonly used, the use of random values ranging from zero to the detection limit was
the selected strategy because, with the use of substitute values that are the same, measurement
variability is under-estimated. Using random values in the range from zero to the detection limit
more closely represents the true, but unknown, variability in the data. More sophisticated methods
(6) are not readily available for multi-factor analysis of variance and could not be used. In addition,
nine or more detections within any group were required before performing statistical analyses.
Most groups had 17 or more detections out of 24 results. Results of statistical analyses are
presented in Tables 3, 5, 7, and 9.
Painted Drywall. CWA and pesticide recoveries from drywall were highly variable and
analyte dependent, ranging from non-detect (ND) (for GB, sampled from a small coupon, using a
Kendall-Curity® wipe, wetted with IPA) to 127 % (for malathion, extracted directly from a small
coupon) (Table 2). Direct extraction of painted drywall yielded recoveries for the target analytes
ranging from ~ 60 % (for GB) to > 80 % (for the other target analytes). Wipe sampling recoveries
for the target analytes were 62 % or less.
14
-------
Table 2. Average" Recoveries (%) for CWA, Pesticides, and Surrogates from Painted Drywall
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
57 ±6
15 ± 12
ND
10 ±3
6 ± 1 b
8 ± 4 b
4 ± 4 b
ND
10 ±0
GD
114 ± 19
30 ±26
24 ±6
11 ± 3
13 ±4
18 ±4
15 ± 1
ND
11 ± 1
HD
82 ± 14
13 ± 7
11 ±3
10 ±2
8 ± 1 b
8 ± 3 b
9 ± 1 b
ND
8 ± 0 b
GF
115 ± 20
40 ±20
24 ±4
5 ± 3 b
19 ±3
27 ±7
21 ± 1
ND
5 ± 0 b
VX
94 ±20
62 ± 17
41 ±7
8 ± 1 b
27 ±3
48 ±29
45 ±4
ND
11 ± 3
MA
127 ±9
55 ± 13
17 ± 16
4 ± 1 b
9 ± 7 b
41 ± 7
17 ±2
ND
ND
DZN
84 ± 12
41 ± 19
18 ±5
6 ± lb
12 ±3
29 ± 11
18 ±2
ND
ND
NB-ds
75 ± 10
57 ±8
63 ±5
71 ± 7
ND
74 ±9
39 ±3
81 ± 16
89 ±7
2-FB
69 ±4
56 ±9
79 ±5
78 ±8
140 ±0
70 ±9
83 ±2
74 ±5
91 ± 7
PCP-ds
84 ±9
88 ±9
86 ± 10
71 ± 6
140 ± 1
113 ± 8
101 ± 1
67 ±7
90 ±7
ter-di4
74 ±6
59 ±7
84 ±7
77 ±5
150 ±0
73 ± 11
87 ±3
72 ±6
90 ±6
small =10 cm2 coupon spiked with 1 |ig analyte; large =100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine,
ter-di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements; b estimated average concentration was
below lowest calibration level
Table 3. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table 2) from
Drywall
Tested Variable(s)
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Wipe
0.48
0.10
0.54
0.025
0.19
0.16
0.16
Wetting Solvent
0.21
0.96
0.99
0.63
0.98
0.0008
0.087
Coupon Size
0.54
0.010
0.11
<0.0001
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent
0.030
0.70
0.30
0.91
0.84
0.56
0.41
Wipe +
Coupon Size
0.62
0.41
0.66
0.78
0.75
0.31
0.95
Wetting Solvent +
Coupon Size
0.20
0.31
0.80
0.021
0.32
<0.0001
0.0033
Wipe +
Wetting Solvent +
Coupon Size
0.96
0.98
0.96
0.057
0.12
0.27
0.29
Note: a p < 0.01 indicates statistical significance; statistically significant values are highlighted and in bold font.
15
-------
ANOVA analyses suggests that coupon size may be an important variable contributing to
statistically-significant differences in recoveries (Table 3). CWA and pesticide recoveries on small
coupons tended to be higher when compared to the larger coupon size for all tested solvents,
although the error associated with the smaller coupons is also larger in some cases, which may be
attributed to the solvent/matrix interactions. The increased ratio of solvent to surface area and the
amount of time the target analytes are exposed to the surface (e.g., drying times on small vs large
coupons) might play a role in higher recoveries for the smaller coupon size. Evaporation of solvent
will most likely be facilitated when the solvent is distributed over a larger surface area. Further
investigation is needed to determine the effect of coupon size and solvent for CWA recovery
efficiencies from these surfaces.
Wetting solvent appeared to be a significant variable for the recovery of malathion as
recoveries using DCM solvent were higher than for IP A. Interactions that occur between solvent
and surface are difficult to determine. Although it is anticipated that DCM would be able to
penetrate the surface of painted drywall to a greater extent than IP A, matrix interferences may also
be greater due to the ability of DCM to compromise the surface and can be verified by examining
matrix blanks. The data suggests that malathion may partition better into DCM than IP A, but may
also be subjected to greater interferences associated with the painted drywall surface and use of
DCM solvent. ANOVA tests also suggest a significant correlation of wetting solvent and coupon
size for malathion and diazinon. From a statistical point of view, there was no clear best
combination of wipe and wetting solvent to remove CWA and pesticides studied from the painted
drywall surface.
Vinyl Tile. Recoveries for target CWAs and pesticides on vinyl tile were highly variable
and analyte dependent (Table 4). For this matrix, volatile CWAs (GB, GD, HD, and GF) were not
recovered from the large coupons when the Kendall-Curity® wipe was used with IPA wetting
solvent or when the Dukal™ wipe was used with either IPA or DCM as a wetting solvent. The
Dukal™ wipe holds less solvent (approximately two times less) than the Kendall-Curity® wipe,
which can be attributed to smaller size or the how the material is woven because both wipes are of
the same weight (12-ply). The inability of the Dukal™ wipe to hold a greater volume of solvent,
may explain, in part, the observed non-detects. The ability of CWAs to easily penetrate into the
vinyl tile might also contribute to low or no recoveries by wipe sampling. It is important to note
that VX recoveries from direct extraction of the small coupons resulted in non-detection of the
CWA, which is unexpected. VX is considered less-volatile than any of the tested CWAs and should
result in a recovery result from the direct extraction process, especially since wiping results
produced recoveries. As stated above, results from the vinyl tile surface were highly variable,
which is likely attributed to the matrix interferences produced from the surface. The direct
extraction process will result in greater matrix effects, and larger quantities of interferents, than
surface wiping because the extraction solvent is directly interacting with the matrix for an extended
time period versus surface wiping. Matrix interferences most likely resulted in the inability to
reliably recover VX from the surface. More investigation is warranted.
16
-------
ANOVA analyses suggest that statistically significant differences in recoveries were
identified for most of the tested analytes, the type of wipe, wetting solvent, and coupon size (Table
5). For the vinyl tile, in general, the Kendall-Curity® wipe with DCM wetting solvent (on a small
coupon) resulted in the highest recoveries. Statistically significant interactions between wipe and
wetting solvent and wetting solvent and coupon size were observed.
Laminate. CWAs and pesticides were not recovered for many of the experiments using
the laminate surface (Table 6). Laminate is not a rough surface and is not considered as porous as
vinyl tile, suggesting the lack of recoveries for GB, GD, HD, and GF might be due to volatilization.
Surrogate recoveries for nitrobenzene-ds- and 2-fluorobiphneyl, which are considered to be
volatile chemicals, were poor when spiked directly on the laminate surface for the direct extraction
experiments. Surrogate recoveries for these two analytes were much higher when they were spiked
directly on the wipes, suggesting that analyte volatility may play an important factor in analyte
recovery from the laminate surface. Concentration effects were outside the scope of this study, but
may help when attempting to understand and address volatilization and/or permeation of chemicals
on a surface. Because the contact time with the surface was short and low concentrations of CWAs
were used to spike the surface, the data suggests that CWAs at low concentrations are not well-
recovered from laminate, most likely due to volatilization. Thus, natural attenuation might be a
feasible decontamination approach in a remediation scenario for non-porous surfaces and areas
where low CWA concentrations are known.
ANOVA analyses could not be performed for CWA analytes GB, GD, HD and GF due to
the fact that too few detections were observed. ANOVA analyses for VX, malathion, and diazinon
did not show any statistically significant differences in recoveries recorded using different wipes,
wetting solvents, or coupon sizes (Table 7).
17
-------
Table 4. Average3 Recoveries (%) for CWA, Pesticides, and Surrogates from Vinyl Tile
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
59 ±2
29 ±5
ND
9 ± 1b
ND
19 ± 1
ND
ND
ND
GD
107 ±6
72 ±2
ND
11 ±3
ND
60 ±4
7 ± 0b
ND
ND
HD
84 ±3
43 ± 1
ND
10 ±3
ND
29 ±3
ND
ND
ND
GF
114 ± 5
96 ±2
16 ±3
20 ±7
ND
81 ±4
12 ± 1
ND
ND
VX
ND
125 ±3
72 ±6
19± 11
27 ±7
134 ± 1
62 ± 11
14 ±2
15 ±4
MA
138 ±6
104 ±3
35 ±2
6 ± 3 b
ND
92 ±2
34 ± 1
ND
ND
DZN
111 ±5
84 ±5
23 ±2
13 ±6
ND
86 ± 1
22 ± 1
ND
ND
NB-ds
78 ±6
56 ±2
73 ±9
74 ±6
76 ±6
88± 11
44 ±4
117 ± 8
91 ±2
2-FB
65 ±4
44 ±2
87 ±4
78 ±5
141 ± 1
78 ±8
92 ± 10
119 ± 4
88 ±2
PCP- ds
41 ±4
75 ±2
99 ±3
76 ±6
125 ± 1
86 ±5
109 ±0
106 ±3
100 ±6
ter-di4
53 ±3
51 ±3
100 ±4
81 ±7
151 ± 1
88 ±7
95 ±10
131 ± 4
104 ±6
small =10 cm2 coupon spiked with 1 |ig analyte; large = 100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-d, = deuterated nitrobenzene, ND = non-detect, PCP- d, = deuterated phencyclidine,
ter-di4= deuterated terphenyl
Note: 11 average of three replicates ± the standard deviation of the measurements; b estimated average concentration was
below lowest calibration level
Table 5. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table 4) from
Vinyl Tile
Tested Variable(s)
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Wipe
0.002(»
o.ooss
0.00S2
0.0002
<)<>:i
ii iiv.
0.0003
Wetting Solvent
<11.1 IIIIII
<0.0001
1 I.I IIIIII
<0.0001
dunlin
<0.0001
<0.0001
Coupon Size
0.0001
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent
<0.0001
0.0031
0.0002
0.0003
0.0043
(i <><.1
<0.0001
Wetting Solvent +
Coupon Size
<0.0001
<0.0001
i i.i ii ii ii
<0.0001
1 I.I IIIIII
<0.0001
<0.0001
Wipe +
Wetting Solvent +
Coupon Size
0.17
0.091
0.10
0.48
0.83
0.62
0.023
Note: a p < 0.01 indicates statistical significance; statistically significant values are highlighted and in bold font.
18
-------
Table 6. Average" Recoveries (%) for CWA, Pesticides, and Surrogates from Laminate
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
10 ±2
ND
ND
ND
ND
ND
ND
ND
ND
GD
14 ±5
ND
ND
ND
ND
ND
ND
ND
ND
HD
14 ±4
ND
ND
ND
ND
ND
ND
ND
ND
GF
26 ±7
ND
ND
ND
ND
ND
ND
ND
ND
VX
50 ± 12
38 ±8
41 ± 18
31 ±2
37 ±6
51 ±6
25 ± 200
30 ±4
26 ±6
MA
100 ± 17
80 ± 18
66 ±26
69 ±5
71 ± 7
69 ±2
59 ±20
71 ± 9
50 ± 1
DZN
74 ± 10
51 ± 7
39 ± 12
45 ± 1
44 ±4
43 ±7
33 ±9
47 ±6
38 ±5
NB-ds
ND
93 ±4
60 ±8
87 ±3
95 ±7
77 ± 34°
39 ±2
87 ± 10
100 ±3
2-FB
6 ± 5 b
84 ±3
60 ±7
84 ±5
89 ±3
73 ±7
70 ± 1
87 ±9
94 ±3
PCP- ds
60 ± 10
85 ±2
76 ±4
72 ±3
88 ±3
84 ±6
80 ±3
82 ±9
96 ±3
ter-di4
104 ± 16
99 ±3
81 ±4
85 ±7
93 ±6
92 ±5
83 ±4
89 ±8
94 ±2
small =10 cm2 coupon spiked with 1 |ig analyte; large =100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine, ter-
di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements;b estimated concentration was below lowest
calibration level; 0 one of the three recoveries was noticeably lower than the others
Table 7. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table 6) from
Laminate
Tested Variable(s)
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Wipe
0.44
0.18
0.13
Wetting Solvent
0.26
0.13
0.014
Coupon Size
0.10
0.64
0.51
Wipe +
Wetting Solvent
Too few
Too few
Too few
Too few
0.047
0.49
0.59
detections
for
statistical
analysis
detections
for
statistical
analysis
detections
for
statistical
analysis
detections
for
statistical
analysis
Wipe +
Coupon Size
0.66
0.95
0.51
Wetting Solvent +
Coupon Size
0.17
0.84
0.32
Wipe +
Wetting Solvent +
0.34
0.34
0.41
Coupon Size
Note: a p < 0.01 indicates statistical significance; statistically significant values are highlighted and in bold font.
19
-------
Coated glass. GB and GD were not recovered from coated glass under any of the sampling
conditions, most likely due to volatilization (Table 8). Only 20 % of the applied HD was recovered
by direct extraction from a coated glass coupon and recoveries for HD were < 20 % for all other
wipe sampling experiments. Recoveries for VX, malathion, and diazinon were > 50 % for the
coated glass surface.
ANOVA analyses could not be performed for GB, GD, and HD, as too many non-detects
were observed resulting in insufficient data. ANOVA analyses for GF, VX, malathion, and
diazinon was performed based on coupon size. The analyses produced statistically significant
differences in recoveries for GF, VX, and malathion (note that the statistical test for diazinon
produced a p-value of 0.01; p-values just below this number indicate statistical significance) (Table
9). For VX, malathion, and diazinon, wetting solvent and coupon size produced significant
differences.
Wood. CWA and pesticide recoveries from the tested wood surface were low when the
surface was directly extracted and non-detectable by wipe extraction. Due to the poor recoveries
from the analytes spiked onto this matrix, no statistical analyses could be performed.
20
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Table 8. Average" Recoveries (%) for CWA, Pesticides, and Surrogates from Coated Glass
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
ND
ND
ND
ND
ND
ND
ND
ND
ND
GD
ND
ND
ND
ND
ND
ND
ND
ND
ND
HD
20 ±4
3 ± 5 b'°
ND
9 ± 1 b
ND
ND
ND
3 ± 5 b'°
ND
GF
16 ±2
15 ±2
13 ±0
25 ±4
19 ±6
ND
ND
21 ± 7
15 ± 1
VX
51 ±7
63 ± 10
96 ± 16
83 ±6
70 ±8
69 ± 10
102 ± 17
81 ± 9
36 ±6
MA
104 ±5
92 ±4
109 ±9
101 ±5
49 ±8
102 ± 12
107 ± 15
92 ±7
28 ± 10
DZN
71 ± 13
76 ±4
71 ± 13
92 ±4
52 ±7
77 ±9
85 ± 15
87 ±6
38 ±4
NB-ds
20 ±7
76 ±4
61 ± 1
95 ±4
66 ±8
91 ± 7
71 ± 17
92 ±3
83 ±3
2-FB
16 ±3
70 ±3
69 ±3
85 ±3
136 ±2
78 ±6
78 ± 10
86 ±2
77 ±4
PCP- ds
69 ±7
72 ± 1
84 ± 1
82 ±2
108 ± 1
82 ± 10
95 ± 11
88 ±3
79 ±4
ter-di4
82 ±8
78 ±2
83 ±5
90 ±2
117 ± 1
90 ±9
90 ± 1
91 ± 4
74 ±4
small =10 cm2 coupon spiked with 1 |ig analyte; large = 100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine,
ter-di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements; b estimated concentration was below
lowest calibration level; 0 two of three measurements were "non-detects"
Table 9. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table 8) from
Coated Glass
Tested Variable(s)
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Wipe
0.011
0.19
0.15
0.75
Wetting Solvent
0.025
0.66
<0.0001
<0.0001
Coupon Size
0.0003
0.003X
<0.0001
0.010
Wipe +
Wetting Solvent
Too few
detections
for
statistical
analysis
Too few
detections
for
statistical
analysis
Too few
detections
for
statistical
analysis
0.39
0.10
0.13
0.79
Wipe +
Coupon Size
0.047
0.017
0.022
0.32
Wetting Solvent +
Coupon Size
0.11
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent +
0.62
0.099
0.97
0.16
Coupon Size
Note: a p < 0.01 indicates statistical significance; statistically significant values are highlighted and in bold font.
21
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Table 10. Average3 Recoveries (%) for CWA, Pesticides, and Surrogatesb from Wood
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
ND
ND
ND
ND
ND
ND
ND
ND
ND
GD
37 ±8
ND
ND
ND
ND
ND
ND
ND
ND
HD
33 ±6
ND
ND
ND
ND
ND
ND
ND
ND
GF
60 ± 13
ND
ND
ND
ND
ND
ND
ND
ND
VX
80 ±40
ND
58 ±8
ND
ND
ND
21 ± 8
ND
ND
MA
173 ± lc
17 ± 1
44 ± 11
ND
ND
ND
ND
ND
ND
DZN
130 ±7
14 ± 1
34 ±6
ND
ND
ND
ND
ND
ND
NB-ds
74 ±21
102 ±9
91 ± 1
91 ±3
ND
94 ±3
71 ± 8
100 ±5
99 ± 1
2-FB
34 ±7
92 ±3
98 ±2
90 ±3
100 ±6
90 ±5
118 ± 2
94 ±3
96 ± 1
ter-di4
88 ±6
119 ± 3
112 ± 2
84 ±2
101 ±7
101 ± 1
123 ±3
83 ± 1
89 ±2
small =10 cm2 coupon spiked with 1 |ig analyte; large = 100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine,
ter-di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements; b deuterated phencyclidine was not used
in this experiment; 0 interference noted
4.3 Recoveries from Direct Extraction versus Wipe Sampling
Average recoveries for CWAs and pesticides by direct extraction of the matrices and those
obtained by wipe sampling of the small coupons were compared using ANOVA (Tables 3, 5, 7,
and 9). The data obtained from the statistical analysis involving coupon size suggests a correlation
between direct extraction, potentially coupon size, and analyte recoveries. Therefore, only data
from the small coupons (and not the large coupons) were considered in the statistical analysis.
ANOVA was used because it allowed the consideration of both wipe type (i.e., Kendall-Curity®
and Dukal™) and wetting solvent (DCM and IPA) for the various matrices. Since the analysis
produced recovery data with many "non-detects," it was not possible to statistically test a
difference between direct extraction of the small coupons and that of wipe sampling using various
combinations of solvents and wipes for every comparison. However for several conditions,
p-values less than 0.01 were observed, indicating that statistically significant differences were
noted (Table 11). The analysis suggests that direct extraction yielded statistically-significant, and
higher CWA recoveries, than wipe sampling for the removal of the following analytes and small
surface coupons (except for VX on vinyl tile, see Section 4.2):
22
-------
GB, from drywall
• GD, from vinyl tile
HD, from drywall
GF, from drywall and vinyl tile
Malathion, from drywall and vinyl tile
Diazinon, from drywall, vinyl tile, and laminate
Although numerous factors (e.g., sampling size, permeability of the surface, solvent
compatibility, volatility, concentration, matrix interferents) may play an important role for
recovering CWAs, CWA recoveries via direct extraction may be greater than performing wipe
sampling on the same surface material. Therefore, wipe sampling may underestimate CWA
concentrations on/in these matrices and a "non-detect" produced by wipe sampling cannot be
equated with a lack of CWA in a material. These factors are important to note when attempting to
accurately interpret results produced by wipe sampling. Furthermore, direct extraction results may
be misleading due to matrix interferences. Careful consideration of extraction solvents, matrix
interferences, and other factors described above are important when evaluating and interpreting
results.
23
-------
Table 11. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table 2)
from Direct Extraction and Wipe Extraction (Small Coupons Only)
Tested Variable(s)
ANOVA p-valuesa
GB
GD
HD
GF
vx
MA
DZN
Drywall
Wipe/Direct Extraction
<0.0001
0.44
<0.0001
<0.0001
0.77
<0.0001
<0.0001
Wetting Solvent
0.19
0.75
0.94
0.22
0.48
0.002"7
(i
Wipe +
Wetting Solvent
0.24
0.92
0.76
0.43
0.58
0.53
0.39
Vinyl Tile
Wipe/Direct Extraction
b
<0.0001
b
<0.0001
<0.0001
<0.0001
<0.0001
Wetting Solvent
<11. Ill IIII
<0.0001
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent
0.0004
uui:
0.029
0.73
114"
Laminate
Wipe/Direct Extraction
b
b
b
b
0.48
0.11
0.0007
Wetting Solvent
0.19
0.34
0.069
Wipe +
Wetting Solvent
0.12
0.89
0.88
Coated Glass
Wipe/Direct Extraction
b
b
b
b
0.010
0.77
0.42
Wetting Solvent
0.0012
0.086
0.81
Wipe +
Wetting Solvent
0.98
0.30
0.36
Wood
Wipe/Direct Extraction
b
b
b
b
b
b
b
Wetting Solvent
Wipe +
Wetting Solvent
Abbreviations: DZN = Diazinon, MA = malathion
Notes: a p < 0.01 indicates statistical significance; statistically significant results are highlighted and shown in bold
font; b indicates too few detections for statistical analysis
4.4 Sample Holding Times for CWAs on Dukal™ Wipes
A sample holding time study was previously performed using the Kendall-Curity® gauze
(3). The Kendall-Curity® gauze was spiked with CWAs and pesticides (0.1-|ig and l-|ig levels),
stored in a refrigerator (~ 4 °C), and extracted and analyzed at various times over the course of a
month to establish stability. All agents were detected after 30 days on the Kendall-Curity® gauze
at the 0.1 |ig per wipe concentration, except GB. Sarin (GB), spiked at 0.1 |ig, was never recovered
at any time point during the study. This previous study also suggested that the CWAs appeared to
be stable over the course of a month at a concentration of 1 |ig per wipe. The recommendation
from the previous study regarding CWA stability was that analysis, or at least the extraction, of
24
-------
CWA samples should occur within a week of collection so that measured concentrations of CWA
would be within -80% of their original values; however, depending on the analyte, a holding time
of 14 days might also be acceptable.
A similar holding time study was performed with the Dukal™ wipes; however, based on
the recommendation for the stability of CWAs on the Kendall-Curity gauze, the length of the
holding time study was only up to two weeks. Dukal™ wipes were spiked with a concentration of
either 0.1 |ig or 1.0 |ig for each CWA per wipe, and stored in a refrigerator. A set of three separate
wipe samples were extracted and analyzed on Days 0, 2, 7, and 14. CWA concentrations on the
Dukal™ wipes are presented in Tables 12 and 14 for each tested day (note that Kendall-Curity®
results from Reference 3 are provided for comparison). Similar to the results of the study with the
Kendall-Curity® wipes, all of the CWAs spiked on the Dukal™ gauze at 1 |ig per wipe, were
detectable on Day 14. At Day 14, the concentration of VX was half of its original value, but it still
greater than the recovery of VX from the Kendall-Curity wipe on Day 14. (Note that the cause of
the low, 0.38 |ig, amount of VX measured on the Kendall-Curity gauze on Day 2 in unknown; it
might possibly be attributed to hydrolysis caused by water inadvertently introduced into the sample
or extraction solvent.) Nonetheless, when VX is a target analyte, the data suggests that both wipes
should be analyzed within seven days. At the 0.1 |ig spiking level, all of the CWA were detectable
at Day 14, with the exception of VX, which was no longer detected at Day 14.
Dunnett's test (7) was performed to compare the CWA amounts measured on the Dukal™
wipes at each time point (i.e., t > 0) with the initial measured CWA amounts (t = 0). The null
hypothesis was that the average CWA concentrations at the later times (t = 2, 7, or 14 days) were
greater than or equal to the initial CWA concentration. The alternative hypothesis was that one or
more average CWA concentrations at a later time was less than the initial CWA concentration (a
one-sided test). Results of these comparisons are presented in Tables 13 and 15.
Although each set of experimental conditions was evaluated repeatedly over time, the
wipes from which samples were extracted were different. That is, the wipe extraction solution
analyzed at any given time point was derived from a different wipe than every other time point.
Therefore, the measurements at each time point were statistically independent of those at other
time points. At a significance level (a) of 0.01 (a conservative value of a = 0.01 was chosen over
the commonly used value of a = 0.05 to compensate for the increased rate of statistical false
positives resulting from multiple applications of Dunnett's test), a statistically significant lower
amount of VX was observed for the Dukal™ wipes spiked at 0.1 |ig and 1 |ig at the Day 14 time
point when compared to other days. While statistically significant decreases were observed in GB
and HD spiked at 0.1 |ig on Day 2 and Day 7, a statistically significant decrease was not observed
at these time points for the Dukal™ wipes that were spiked at the l-|ig level. None of the Dukal™
wipes showed a statistically significant decrease in GB or HD on Day 14 when compared to Day
0. Thus, the recommendation that CWA samples should be extracted and analyzed within a week
of collection may also be applied to samples collected with Dukal™ wipes. The holding time period
established for the Dukal™ wipe was consistent with that of the Kendall-Curity® wipe.
25
-------
Table 12. Holding Time Study Data, 1 jig Each CWA on Wipes
Dukal™ Wipe - measured CWA amount" (|ig)
Kendall-Curity® Wipeb- measured CWA amount (|ig)
Day 0
Day 2
Day 7
Day 14
Day 0
Day 2
Day 7
Day 14
GB
1.07 ±0.04
1.07 ±0.07
0.97 ±0.05
1.12 ± 0.12
0.89 ±0.03
0.89 ±0.03
0.91 ±0.03
0.9 ±0.03
GD
1.51 ± 0.11
1.38 ± 0.11
1.51 ± 0.16
1.42 ±0.20
0.96 ±0.03
0.99 ±0.02
1.02 ±0.02
1.01 ±0.02
HD
1.11 ±0.06
1.16 ± 0.10
1.08 ±0.07
1.16 ± 0.13
0.94 ±0.04
0.81 ±0.02
0.92 ±0.02
0.82 ±0.04
GF
1.47 ±0.13
1.27 ±0.10
1.26 ±0.14
1.50 ±0.17
1.08 ±0.06
1.15 ±0.05
1.16 ±0.02
1.18 ±0.03
VX
1.02 ±0.09
0.91 ±0.06
1.06 ±0.09
0.53 ±0.17
1.02 ±0.06
0.38 ± 0.03
0.96 ±0.02
0.32 ± 0.03
a Average amounts ± standard deviation of the measurements of CWA on three wipes, stored in a VOA vial under
refrigeration (2-4 °C) for 0, 2, 7, and 14 days after spiking on Day 0 with 1 |ig of each CWA; b data from previous
study (3). Shaded/bold cells indicate a statistically significant recovery difference from Day 0.
Table 13. Statistical Analysis of Holding Time Study Data, 1 jig Each CWA on Dukal™ Wipes
p-values" from Dunnett's Test
1 fig each CWA on Dukal™ Wipe
Analyte
ti — to
t7~ to
tl4 — to
GB
0.769
0.159
0.940
GD
0.319
0.740
0.436
HD
0.900
0.578
0.915
GF
0.123
0.113
0.842
VX
0.293
0.873
<0.001
Notes: a p-values for comparison of 2, 7, and 14-day time point amounts and the measured amount
at the start of the experiment (t=0); p-value < 0.01 [in bold] indicates statistically significant concentration
decrease.
26
-------
Table 14. Holding Time Study Data, 0.1 jig Each CWA on Wipes
TM
Dukal Wipe (jig)
Kendall-Curity® Wipe3 (jig)
Day 0
Day 2
Day 7
Day 14
Day 0
Day 2
Day 7
Day 14
GB
0.16 ± 0.01
0.13 ±0.00
0.12 ± 0.00
0.21 ±0.01
ND
ND
ND
ND
GD
0.11 ±0.01
0.08 ±0.01
0.10±0.01
0.13 ±0.01
0.11 ±0.01
0.12 ±0.01
0.14 ±0.01
0.15 ±0.01
HD
0.14 ± 0.01
0.10 ±0.00
0.10 ±0.01
0.22 ±0.01
0.10 ±0.00
0.09 ±0.03
0.11±0.01
0.08 ±0.01
GF
0.25 ±0.10
0.19 ±0.00
0.19 ±0.03
0.12 ±0.10
0.11±0.01
0.13 ±0.02
0.13 ±0.01
0.14± 0.00
VX
0.19 ±0.00
0.16 ±0.01
0.13 ±0.01
ND
0.11±0.01
0.09 ±0.02
0.10 ±0.01
0.10± 0.06
a Average amounts ± standard deviation of the measurements of CWA on three wipes, stored in a VOA vial under
refrigeration (2-4 °C) for 0, 2, 7, and 14 days after spiking on Day 0 with 0.1 ng of each CWA; b data from previous
study (3). Shaded/bold cells indicate a statistically significant recovery difference from Day 0.
Table 15. Statistical Analysis of Holding Time Study Data, 0.1 jig Each CWA on Dukal™ Wipes
p-valuesa from Dunnett's Test
0.1 fig each CWA on Dukal™ Wipe
Analyte
ti — to
t7— to
tl4 — to
GB
0.006
<0.001
1
GD
0.029
0.391
0.974
HD
0.001
0.001
1
GF
0.073
0.084
0.011
VX
0.221
0.021
<0.001
Notes: a p-values for comparison of 2, 7, and 14-day time point amounts and the measured amount
at the start of the experiment (t=0); p-value < 0.01 [in bold] indicates statistically significant concentration
decrease.
4.5 VX-di4 as an Extracted Internal Standard
Surrogates and internal standards used in the current CWA method (e.g., Method 8270
surrogates and internal standards [4]) are not similar in chemistry to the CWAs. Furthermore,
CWAs deposited on porous surfaces presents numerous complications, from matrix interferences
to surface interactions and permeation into the surfaces, making recoveries from these matrix types
difficult. VX-di4, synthesized by LLNL, could be used to provide valuable information on some
of these complications and potentially allow for more accurate quantification of VX itself. Thus,
VX-di4 was spiked (at the 1 |ig level) onto the investigated surfaces (immediately after the surfaces
were spiked with unlabeled CWA) and used to quantify VX. Data comparing VX recoveries, from
conventional calibration curves and from the response of the deuterated extracted internal standard
(IS) (VX-di4 listed as VX by IS) are presented in Table 16. In almost all cases, recoveries using
the response of VX-di4to calculate VX responses are closer to 100 % (assuming 100 % recovery
efficiency, i.e., that 100 % recovery is possible from the matrix) than those that do not use the
27
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deuterated extracted internal standard (i.e., calibration curves). The data suggest that the use of
VX-di4 allows for a more accurate estimation of VX concentrations at low concentrations or when
VX recovery efficiencies are problematic. Spiking an isotopically labelled surrogate onto the
surface provided valuable information regarding analyte recoveries and potential matrix
interferents with specific surfaces. Experiments involving the spiking of VX-di4 onto wipe
materials prior to sample processing and wipe extraction are still needed to confirm that VX losses
on wipe materials are minimal. However, data collected from the direct extraction of the coupon
materials provides an approximation of possible losses from these processes. Based on the data
presented in Table 16 (using VX-di4), losses from sample processing procedures appears minimal.
Table 16. Average" Recoveries (%) for VX, from Various Matrices, with VX-di4 as an Extracted
Internal Standard (Listed as VX by IS) and without (listed as VX)
Direct
KC
KC
KC
KC
Dukal
Dukal
Dukal
Dukal
extraction
DCM
I PA
DCM
I PA
DCM
IPA
DCM
IPA
small
small
small
large
large
small
small
large
large
l)n \\iill
VX
94 ±20
62 ± 17
41 ± 7
8 ± 1b
27 ±3
48 ±29
45 ±4
ND
11 ±3
VXbylS
90 ± 7 0
87 ±6
80 ±8
97 ±8
87 ±2
100 ±7
86 ±7
ND
85 ± 10
Yiinl
Tile
VX
ND
125 ±3
72 ±6
19 ± 11
27 ±7
134 ± 1
62 ± 11
14 ±2
15 ± 4
VXty/S'
ND
118 ± 4
129 ±8
127 ±6
84 ± 1
114 ± 5
150 ±9
94 ±2
106 ±9
Laminate
VX
50 ± 12
38 ±8
41 ± 18
31 ±2
37 ±6
51 ±6
25 ± 20 d
30 ±4
26 ±6
WbylS
94 ±5
78 ± 13
64 ± 28 d
80 ±5
75 ±3
72 ± 15
50 ± 18 d
73 ±4
73 ±8
('(tilled (iliISS
VX
51 "
Oj ± 10
96 ± 16
83 ±6
70 ±8
69 ± 10
102 ± 17
81 9
3o ± 6
VXty/S'
101 ±9
107 ±7
97 ±8
118 ± 2
87 ± 10
105 ±4
110 ± 4
116 ± 4
91 ± 10
Wood
VX
80 ±40
ND
58 ±8
ND
ND
ND
21 ± 8
ND
ND
VXbylS
82 ±3
57 ±6
57 ±5
ND
56 ±2
63 ±7
56 ±2
ND
ND
small = coupon of 10 cm2 surface area, large=coupon with 100 cm2 surface area
Abbreviations: DCM=dichloromethane, IPA=isopropanol, KC=Kendall-Curity wipe, ND=not detected.
Note: a average of three, independent replicates ± the standard deviation of the measurements; b estimated average
c d
concentration was below lowest calibration level; average of two values, potential outlier ignored; one of three
measurements markedly different from the others.
28
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5.0 Conclusions and Recommendations
It is recommended that both tested gauze wipes (Dukal™ and Kendall-Curity®) be pre-
cleaned, by solvent extraction, before use due to contaminants present in both wipe materials that
may interfere with the analysis of target analytes (specifically VX). Both wipe materials performed
well and maintained their physical integrities during the wipe sampling process. For several of the
analyte and surface combinations, the Kendall-Curity® gauze wipes yielded higher analyte
recoveries. Several factors, or combinations thereof, may attribute to higher recovery yields when
using either wipe, such as larger wipe size, solvent effects, and surface material effects. It is worth
noting that after both wipes were cleaned, they possessed similar wipe characteristics and
composition based on the signatures presented in the chromatograms from analysis of the
materials. Regardless, a larger solvent volume may result in greater recovery efficiencies for the
target CWA analytes on the tested porous surfaces based on the data presented in the tables.
Holding time studies conducted with 1 |ig of each CWA and pesticide spiked on a Dukal™
wipe, placed in a VOA vial, and refrigerated, suggest that most analytes were stable and could be
stored for 14 days. VX was the only exception, which was detected at -50% of its original
concentration after two weeks on the Dukal™ wipe. VX was still within range of its original
concentration on Day 7, suggesting that VX is stable over this time period. The results for the
Dukal™ wipe were similar to an earlier holding time study with the Kendall-Curity® wipes. Thus,
it is recommended that wipe samples containing CWA should be extracted and analyzed within a
week of collection.
Wipe recoveries of CWAs and pesticides varied depending on the analyte, surface, and
(sometimes) wetting solvent used for wipe sampling. There was no clear preferred combination of
wipe and wetting solvent that was optimal for CWA sampling on the various surfaces. In general,
recoveries from the surfaces were greater by direct extraction than those obtained by wipe
sampling, as evidenced from ANOVA analysis for GB, GF, HD, diazinon, and malathion spiked
on painted drywall and GD, HD, VX, diazinon, and malathion spiked on vinyl tile. The more
volatile CWAs were not recovered from laminate or coated glass, which are not considered to be
as porous as the other tested surfaces. Surrogate recoveries for nitrobenzene-ds and 2-
fluorobiphenyl, also considered volatile chemicals, were poor when spiked directly on the surfaces
during the direct extraction experiments. Surrogate recoveries for these two analytes were much
higher when they were spiked directly on the wipes, suggesting that analyte volatility may play an
important factor in analyte recovery from the surface. Concentration effects were outside the scope
of this study, but may help when attempting to understand and address volatilization and/or
permeation of chemicals on a surface. It is likely that the more volatile agents were not detected
in measurable quantities because these volatile CWAs do not persist on these surfaces at low
concentrations. Only a few of the CWAs or pesticides were recovered to a measureable extent on
wood; only VX, diazinon, and malathion were recovered under certain conditions, such as
sampling from the small coupons.
29
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Many of the analyte recoveries were, from a statistically significantly standpoint, higher
for small coupons (surface area 10 cm2) than for the large coupons (surface area 100 cm2). There
may be many factors (material type, wipe type, wetting solvent, volatilization, etc.) that can affect
analyte recovery from porous surfaces and further investigation is needed to decide if surface area
plays a significant role with respect to recovery efficiencies.
The use of VX-di4, to calculate VX quantification, improved recovery values (and were
closer to 100 % recovery efficiency) at low concentrations, or when VX recoveries are
problematic, than those that did not use the VX-di4 extracted internal standard (calibration curve
was used instead). Data suggest that the use of a labelled extracted internal standard is desirable
for a more accurate quantification of VX on porous surfaces. Spiking an isotopically labelled
surrogate onto the surface provided valuable information regarding analyte recoveries and
potential matrix interferents (enhancement/suppression effects) with specific surfaces. However,
it will not be ideal to spike surfaces directly with a hazardous compound, even if it is spiked below
clearance levels. Further investigation is still needed to evaluate the spiking of VX-di4 onto wipe
materials prior to sample processing and wipe extraction instead of the surface itself. Spiking wipe
materials with VX-di4 in the lab, prior to sample processing and analysis, will still provide useful
information with respect to matrix interferences and analyte recoveries without introducing a
hazardous chemical in the field.
Knowing the limitations of wipe sampling for particular surfaces is critical in order to
correctly interpret and use the results that wipe sampling provides, with respect to recovery
efficiency. Before wipe sampling is performed at a contaminated site, it is essential to understand
the data quality objectives and questions that are to be addressed from the sampling efforts. The
results from a wipe sampling campaign can only be interpreted in the context of meeting
preselected study obj ective(s) and with an understanding that the agent of interest might still reside,
in significant quantities, in and/or under the surface of the material sampled by wiping, especially
for porous/permeable surfaces. On such surfaces, a "non-detect" produced by wipe sampling
cannot be equated with result that CWA is not present in a material.
30
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6.0 References
1. A Literature Review of Wipe Sampling Methods for Chemical Warfare Agents and Toxic
Industrial Chemicals, EPA/600/R-07/004, January 2007, prepared by Battelle, Columbus,
OH 43201, for Stephen Billets, U.S. Environmental Protection Agency, Office of
Research and Development National Exposure Research Laboratory, Environmental
Sciences Division, Las Vegas, NV 89119.
2. Sampling of Common Pesticides and PCBs from Inert Surfaces, EPA/3 30/1-90-001,
October 1989, prepared by B. L. Carr and D. F. Hill, National Enforcement
Investigations Center, Denver, CO. Washington DC: Office of Enforcement and
Compliance Testing, U.S. Environmental Protection Agency.
3. Chemical Warfare Agents Wipe Sampling Collection Efficiencies and Holding Time
Studies, LLNL-TR-450992, Lawrence Livermore National Laboratory, August 2010.
4. Method 8270D: Semivolatile Organic Compounds by Gas Chromatography/Mass
Spectrometry (GC/MS), Rev. 4, February 2007, U.S. Environmental Protection Agency.
5. R Core Team. (2012) R: A language and environment for statistical computing. R
Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0. Accessed
September 10, 2014, URL http://www. R-proi ect.org/.
6. Pro UCL Version 5.0.00, Technical Guide, Statistical Software for Environmental
Applications for Data Sets with and without Nondetect Observations, EPA/600/R-07/041,
September 2013, Prepared by Anita Singh and Ashok K. Singh, U.S. Environmental
Protection Agency, Office of Research and Development, Washington, DC 20460.
7. Multiple Comparisons, Theory and Methods (Chapter 3), by Hsu, J. C., 1996, Chapman &
Hall, NY (ISBN 0 412 98281 1).
8. 3M Window Film FAQs, Accessed January 4, 2016, URL
http://solutions.3m.com/vvps/portal/3M/en US/Window Film/Solutions/Resources/Reso
urces List/FAQs/
9. Verification of Methods for Selected Chemical Warfare Agents (CWAs), January 2013,
U.S. Environmental Protection Agency, EPA/600/R-12/653.
31
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Appendix A: Sample Preparation, Extraction, and Analysis of
Chemical Warfare Agents from Porous/Permeable Surfaces
Revision 1
United States Environmental Protection Agency
Cincinnati, OH 45268
A-l
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Disclaimer
The U.S. Environmental Protection Agency through its Office of Research and Development funded and
managed the research described here under contract DE-AC52-07NA27344 to U.S. Department of Energy
by Lawrence Livermore National Laboratory under Interagency Agreement #DW89922616-01-0. It has
been subjected to the Agency's review and has been approved for publication. Note that approval does not
signify that the contents necessarily reflect the views of the Agency. Mention of trade names, products, or
services does not convey official EPA approval, endorsement, or recommendation.
Questions concerning this document or its application should be addressed to:
Stuart Willison, Ph.D.
U.S. Environmental Protection Agency
National Homeland Security Research Center
26 W. Martin Luther King Drive, MS NG16 Cincinnati, OH 45268
513-569-7253
Willison.Stuart@epa.gov
or
Romy Campisano (EPA Project Officer)
U.S. Environmental Protection Agency
National Homeland Security Research Center
26 W. Martin Luther King Drive, MS NG16
Cincinnati, OH 45268
513-569-7016
Campisano.Romy@epa.gov
A-2
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Acknowledgements
We would like to acknowledge the following individuals and organization for their contributions towards
the development and/or review of this method.
United States Environmental Protection Agency (EPA)
Office of Research and Development, National Homeland Security Research Center
Stuart Willison
Romy Campisano
Lukas Oudejans
Office of Site Remediation and Restoration
Elise Jakabhazy
Office of Land and Emergency Management
Larry Kaelin
Lawrence Livermore National Laboratory (LLNL)
Forensic Science Center
95th Civil Support Team (CST), Weapons of Mass Destruction (WMD), Hayward, CA.
A-3
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TABLE OF CONTENTS
SECTION PGNO.
DISCLAIMER A-2
ACKNOWLEDGMENTS A-2
LIST OF TABLES vii
LIST OF ACRONYMS AND ABBREVIATIONS A-5
1. INTRODUCTION A-7
2. SCOPE AND APPLICATION A-7
3. SUMMARY OF SAMPLING AND ANALYSIS PROCEDURE A-8
4. DEFINITIONS A-8
5. INTERFERENCES A-10
6. HEALTH AND SAFETY A-10
7. EQUIPMENT AND SUPPLIES A-10
8. REAGENTS AND STANDARDS A-12
9. SAMPLE COLLECTION, PRESERVATION AND STORAGE A-13
10. QUALITY CONTROL A-15
11. INSTRUMENT CALIBRATION AND STANDARDIZATION A-19
12. ANALYTICAL PROCEDURE A-20
13. DATA ANALYSIS AND CALCULATIONS A-22
14. METHOD PERFORMANCE A-23
15. POLLUTION PREVENTION A-23
16. WASTE MANAGEMENT A-24
17. REFERENCES A-25
18. TABLES AND VALIDATION DATA A-26
A-4
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Abbreviations/Acronyms
2-FB
2-fluorobiphenyl
ANOVA
Analysis of Variance (statistical analysis technique)
AS
Analytical Standard
CAL
Calibration Standard
CCV
Continuing calibration verification
CWA
Chemical Warfare Agent
DCM
Dichloromethane
DZN
Diazinon
EPA
United States Environmental Protection Agency
ERLN
Environmental Response Laboratory Network
GB
Sarin (O-Isopropyl methylphosphonofluoridate)
GC
Gas Chromatograph
GC/MS
Gas Chromatography/Mass Spectrometry
GD
Soman (3,3-Dimethyl-2-butyl methylphosphonofluoridate)
GF
Cyclosarin (O-Cyclohexyl methylphosphonofluoridate)
HD
Sulfur mustard (distilled) (/i/.v(2-chloroethvl)sulfide)
IDC
Initial Demonstration of Capability
IPA
Isopropanol
IS
Internal Standard
KC
Kendall Curity® Gauze
LFMS
Laboratory Fortified Matrix Spike
LFMSD
Laboratory Fortified Matrix Spike Duplicate
LLNL
Lawrence Livermore National Laboratory
LMB
Laboratory Method Blank
MA
Malathion
MDL
Method Detection Limit
MRL
Method Reporting Limit
MS
Mass Spectrometer
NB-ds
Nitrobenzene-ds
ND
Non-detect
NIST
National Institute of Standards and Technology
NMR
Nuclear Magnetic Resonance Spectroscopy
OP
Organophosphorus pesticide
PFTBA
Perfluorotributylamine
P/N
Part Number
PTFE
Polytetrafluoroethylene
QC
Quality Control
SD
Standard Deviation
SDS
Safety Data Sheet
ss
Surrogate Standard
sss
Stock Standard Solution
ter-di4
Terphenyl-d-14
A-5
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TIC
Total Ion Chromatogram
VOA
Volatile Organic Analysis
v/v
Volume/volume percent
VX
<9-cthyl-S'-(2-diisopropylaminocthyl) methylphosphonothioate
VX- di4
Deuterated 0-cthyl-S'-(2-diisopropylaminocthyl) methylphosphonothioate
A-6
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1.0 Introduction
Additional commercially-available materials need to be tested when sampling for Chemical
Warfare Agents (CWAs). A Dukal™ gauze wipe was tested for contaminants that might interfere with CWA
detection and a two-week long stability study was performed to determine the stability of CWA spiked on
a Dukal™ wipe, when stored under refrigerated conditions (2-4 °C). This study is follow-on work stemming
from previous collected data (3), which identified Kendall-Curity® gauze as the preferred wipe based on
holding time stability studies and contaminants/interferences present in the material.
This investigation tested specific (CWAs), including sarin (GB), soman (GD), cyclosarin (GF),
sulfur mustard (HD), and (^-c thy 1 -,S'-(2-di i sopropy 1 am i noethy 1) methylphosphonothioate (VX) on the non-
ideal (e.g., porous and permeable) surfaces of drywall, vinyl tile, wood, laminate, and coated glass.
Pesticides (diazinon and malathion) were used so that a comparison is possible with existing literature data
(1). Experiments included testing with coupons having surface areas of 10 cm2 and 100 cm2. The 10-cm2
coupons were of a size that could easily be extracted in a 2-oz jar (to provide comparative data for CWA
recoveries generated by direct extraction) and the 100-cm2 coupons better represented the area of a surface
that might typically be sampled by wipe extraction. In addition, CWA, at a normalized surface
concentration of 0.1 |_ig per cm2 surface area, were spiked on coupons of the tested surfaces. Wipes were
wetted with either dichloromethane (DCM) or isopropanol (IPA) before sampling for CWA. Experimental
parameters include multiple wipe types, porous/permeable surfaces, coupon surface area, solvent used to
wet the wipe (i.e., wetting solvent), and the utility of VX-di4 as an extracted internal standard.
2.0 Scope and Application
The sampling and analysis procedure was derived from an existing procedure (2, 3, 4) and used to
determine recovery efficiencies of wipe extracts from CWAs on a surface. CWA and the pesticide wipe
recoveries from painted drywall, vinyl tile, laminate, coated glass, and wood surfaces were expected to be
analyte-dependent, matrix-dependent, and highly variable due to the properties associated with
porous/permeable surfaces. Large (100 cm2 surface area, spiked with 10 jj.g each analyte) and small (10
cm2 surface area, spiked with 1 |_ig each analyte) coupons included GB, GD, HD, GF, VX, diazinon, and
malathion and were investigated using various extraction conditions. Wipe sampling experiments were
performed using Kendall-Curity® or Dukal™ wipes and with DCM or IPA as the wetting solvent. The wipe
recovery efficiencies apply to the wipes, wetting solvents, and surfaces tested within this procedure and
should be viewed as general recoveries for surfaces, as the trend may not apply to all tested analytes and/or
matrix.
A-7
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The analytes considered by this procedure include:
Analyte
Abbreviation
CAS RegistrySM
Number
Sarin (GB),
GB
107-44-8
O-Isopropyl methylphosphonofluoridate
Soman (GD),
GD
96-64-0
3,3 -Dimethyl-2-butyl methylphosphonofluoridate
Sulfur mustard (HD),
HD
505-60-2
/i/.v(2-chloroethyl)sulfide
Cyclohexyl sarin (GF),
O-Cyclohexyl methylphosphonofluoridate
GF
329-99-7
vx,
<9-ethyl ,S'-|2-(diisopropylamino)ethyl |
VX
50782-69-9
methylphosphonothioate
3.0 Summary of Sampling and Analysis Procedure
Target CWAs were spiked onto various porous/permeable surfaces such as painted drywall, wood, and
vinyl tile. Polymer-coated glass and laminate surfaces were also tested. Two different-sized coupons (10
cm2 and 100 cm2) from the surfaces were investigated. The smaller coupons were either directly extracted
in vials or wiped; the wipes extracted for analysis using an existing procedure for CWAs (2). The larger
coupons were wiped and extracted for analysis. Both coupon sizes were wiped with either a Kendall-Curity®
or a Dukal™ cotton gauze wipe and the wipe extracts were analyzed by the same analytical procedure.
Wetting solvents consisted of either dichloromethane (DCM) or isopropanol (IPA); there was no definitive
solvent between the two tested solvents. After the surface was wiped with the appropriate wipe material,
the collected wipe sample was spiked with surrogate standards and extracted with dichloromethane, using
a shaker table. The resulting sample extract was concentrated, internal standards were added, and the sample
was analyzed by gas chromatography/mass spectrometry (GC/MS).
4.0 Definitions
4.1 ANALYSIS BATCH - A set of samples analyzed on the same instrument within a 24-hour
period and including no more than 20 field samples, beginning and ending with the analysis
of the appropriate continuing calibration verification (CCV) standards. Additional CCVs
may be required depending on the number of samples (excluding quality control (QC)
samples) in the analysis batch and/or the number of field samples.
4.2 CALIBRATION STANDARD (CAL) - A solution prepared from the analyte stock
standard solution (AS) and the surrogate/internal standard(s). The CAL solutions are used
to calibrate the instrument response with respect to analyte concentration.
A-8
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4.3 CONTINUING CALIBRATION VERIFICATION (CCV) - A calibration standard
containing the method analytes and surrogate standard(s). The CCV is analyzed
periodically to verify the accuracy of the existing calibration for those analytes at or near
the mid-level concentrations. Low calibration concentrations can be added, in addition to
mid-level concentrations, for further accuracy, but are not required.
4.4 EXTRACTION BATCH - A set of up to twenty field samples (excluding QC samples)
extracted together using the same solvents and surrogate (s).
4.5 LABORATORY FORTIFIED MATRIX SPIKE (LFMS) - A field sample to which known
quantities of the method analytes are added in the laboratory. The LFMS is processed and
analyzed exactly like a sample, and its purpose is to determine whether the sample matrix
contributes bias to the analytical results. The background concentrations of the analytes in
the sample matrix must be determined in a separate sample.
4.6 LABORATORY FORTIFIED SAMPLE MATRIX DUPLICATE (LFMSD) - A duplicate
of the field sample used to prepare the LFMS. The LFMSD is fortified and analyzed
identically to the LFMS. The LFMSD is used to assess method precision when the observed
concentrations of method analytes are low.
4.7 LABORATORY METHOD BLANK (LMB) - A blank matrix that is treated exactly the
same as a sample including exposure to all glassware, equipment, solvents and reagents,
and surrogate standards that are used in the analysis batch. The LMB is used to determine
if method analytes or other interferences are present in the laboratory environment, the
reagents, or the apparatus.
4.8 METHOD DETECTION LIMIT (MDL) - The minimum concentration of an analyte that
can be identified, measured, and reported with 99% confidence that the analyte
concentration is greater than zero.
4.9 MINIMUM REPORTING LEVEL (MRL) - The minimum concentration that can be
reported as a quantitated value for a method analyte in a sample following analysis. This
defined concentration can be no lower than the concentration of the lowest calibration
standard for that analyte and can be used only if acceptable QC criteria for this standard
are met.
4.10 SAFETY DATA SHEET (SDS) - Written information provided by vendors concerning a
chemical's toxicity, health hazards, physical properties, fire, and reactivity data including
storage, spill, and handling precautions.
4.11 SURROGATE STANDARD (SS) - A pure chemical(s) added to a standard solution in a
known amount(s) and used to measure the relative response of other method analytes that
are components of the same solution. The surrogate standard must be a chemical that is
structurally similar to the method analytes, has no potential to be present in samples, and
is not a method analyte.
4.12 STOCK STANDARD SOLUTION (SSS) - A concentrated solution containing one or
more method analytes prepared in the laboratory using assayed reference materials or
purchased from a reputable commercial source.
A-9
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A-10
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5.0 Interferences
Procedural interferences can be caused by contaminants in solvents, reagents, glassware and other apparatus
that lead to discrete artifacts or elevated baselines in the selected ion current profiles. All of these materials
must routinely be demonstrated to be free from interferences by analyzing Laboratory Method Blanks
(LMBs) under the same conditions as the samples. Subtraction of blank values from sample results is not
performed.
5.1 All reagents and solvents should be of pesticide grade purity or higher to minimize
interference problems. All glassware should be cleaned and demonstrated to be free from
interferences.
5.2 Matrix interferences may be caused by contaminants from the sample matrix, sampling
devices or storage containers. The extent of matrix interferences will vary considerably
from sample source to sample source, depending upon variations in the sample matrix.
Matrix interferences and contaminants are likely to be present and may have an effect on
the recoveries for the analytical procedure. These interferences lead to elevated baselines
and artifacts that may be interpreted as false positives. Wipes were pre-cleaned using
Soxhlet extraction with dichloromethane prior to use to eliminate possible interferences
from the wipe matrix (Figures A-4-6).
6.0 Health and Safety
The toxicity and carcinogenicity of each reagent used in this method have not been defined precisely. For
this reason, each chemical compound was treated as a health hazard. GB, GD, GF, and VX are nerve agents;
HD is a blister agent. Safety Data Sheets (SDSs) for these chemicals, as well as for the solvents, were
reviewed prior to initiating experimental work. Exposure to all chemicals was reduced to the lowest possible
level and proper protective equipment was worn for protection of skin, eyes, etc.
Personal protective equipment used included nitrile gloves, laboratory coats, and safety glasses with side
shields or goggles. Nitrile gloves were changed frequently, between each operation or after known or
suspected contact with hazardous material. All work was performed in chemical fume hoods. Sample
manipulations were performed in secondary containment (e.g., photo trays) to allow quick cleanup in the
event of a spill. Vial trays were used to hold vials and minimize the potential for tipping.
7.0 Equipment and Supplies
The mention of trade names or commercial products is for illustrative purposes only, and does not constitute
an endorsement or exclusive recommendation for use. The products and instrument settings cited here
represent those products and settings used during method development and experimental studies.
Glassware, reagents, supplies, equipment, and settings other than those listed in this procedure may be used,
provided that method performance appropriate for the intended application has been demonstrated and
documented.
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7.1 GC/MS INSTRUMENT
7.1.1 GAS CHROMATOGRAPHY (GC) SYSTEM - An Agilent (Agilent
Technologies, Inc., Santa Clara, CA) 7890 GC analytical system was used and
equipped with all required accessories including syringes, solvent degasser, and
autosampler.
7.1.2 ANALYTICAL COLUMN - GC Agilent (Agilent Technologies, Inc., Santa
Clara, CA) HP-5MS, 30 m x 0.25 mm i.d. x 0.25 (im film thickness
7.1.3 MASS SPECTROMETER (MS) SYSTEM - An Agilent 5975C MS (Agilent
Technologies, Inc., Santa Clara, CA) mass spectrometer was used in the
development of this method. The GC/MS should be tuned and calibrated, as
needed, per the vendor's instructions and specifications.
7.1.4 DATA SYSTEM - The GC/MS should be controlled by software that allows the
continuous acquisition and storage on machine-readable media of all mass spectra
obtained throughout the duration of the chromatographic program. The software
used with the GC/MS system was MSD ChemStation G1701EA, E.02.02.1431.
7.2 EXTRACTION AND CONCENTRATION APPARATUS
7.2.1 Shaker table, digital pulse mixer (model 099A LC1012, Glas-Col, LLC, Terre
Haute, IN)
7.2.2 RapidVap unit, customized to accommodate 40-mL vials (LabConco, Kansas
City, MO)
7.2.3 Pierce Reacti-Therm™ III (P/N 18824, heating module equipped with the Pierce
Reacti-Therm III, P/N 188 evaporation module, ThermoScientific, Hudson, NH)
7.3 GLASSWARE AND MISCELLANEOUS SUPPLIES
7.3.1 Wipes, 3 in. x 3 in., sterile, cotton gauze (Kendall-Curity, 12-ply, P/N 1903, Tyco
Heathcare Group LP, Mansfield, MA) (Figure A-l).
7.3.2 Wipes, 2 in. x 2 in., sterile gauze (sold by Fisher Scientific, Pittsburg, PA, as North
Co. by Honeywell, P/N 17986486; it should be noted that the wipe received was a
gauze wipe, 2 in. x 2 in, 12-ply, made by Dukal Corp. Ronkonkoma, NY) (Figure
A-l).
7.3.3 40-mL VOA vials with PTFE-lined screw caps (P/N 0040-0310-PC,
Environmental Sampling Supply, Oakland, CA)
7.3.4 2-mL autosampler vials with silver crimp caps (P/N 5182-0543 for vials and P/N
5183-4499 for caps, Agilent, Santa Clara, CA)
A-12
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7.3.5 Painted drywall - standard, Yi" drywall was obtained as surplus from onsite LLNL
facilities and are representative samples from commercial hardware stores. Two
coats of combination paint and primer (Ultra-Pure White, Interior Matte, Behr
Premium Plus Ultra, acrylic paint, P/N 175001, Behr Corp. Santa Ana, CA) were
applied to the drywall (Figure A-2).
7.3.6 Polymer-coated glass - glass coupons were cut from commercial window glass by
Livermore Glass Company (Livermore, CA). Once cut, a coating (Prestige
coating, P/N PR-70, run number 3024324013, 3M, St. Paul, MN) was applied per
manufacturer's instructions (5) (Figure A-2).
7.3.7 Wood - surplus plywood was obtained from onsite LLNL facilities and are
representative samples from commercial hardware stores (top layer of solid wood
is 3/32" thick) (Figure A-2).
7.3.8 Vinyl tile - 1/8", White (Excelon Sanddrift, P/N VCT 51858-45SF, Armstrong,
Lancaster, PA) (Figure A-2).
7.3.9 Laminate tile (laminate countertop') - 3' x 8' sheet, White (Designer White, P/N
d354-60, S/O, Wilsonart LLC, Temple, TX) (Figure A-2).
7.3.10 Helium, ultra-high purity (UHP, Airgas, Radnor, PA)
7.3.11 Pipettes, of various volumes (Rainin pipettes from Mettler-Toledo, Columbus,
OH). Need to measure variable volumes ranging from 1 (iL to 10 mL.
8.0 Reagents and Standards
Laboratories should follow QC procedures to determine when the standards should be replaced. Label all
standards and verify the correct grade of solvents. Reagent-grade chemicals should be used, unless
otherwise indicated. Traceability of materials and standards are established by the manufacturer's
specifications provided at time of purchase. Laboratories should follow established, pre-determined QC
protocols and procedures for handling CWAs.
8.1 Solvents and Reagents - Dichloromethane (AMD Chromasolv®, >99.8% for GC, P/N
34897-6X1L, Sigma-Aldrich, St. Louis, MO). Isopropanol (anhydrous, 99.5%, P/N
278475-1L, Sigma-Aldrich, St. Louis, MO).
8.2 The following surrogate standards were used: a mixed standard containing nitrobenzene-
ds, 2-fluorobiphenyl, and terphenyl-di4, all at 1000 (ig/mL (P/N ERB-076, Cerilliant,
Round Rock, TX); phcncyclidinc-ds. 1000 (ig/mL (P/N P-006, Cerilliant).
8.3 The following internal standards were used l,4-dichlorobenzene-d4, naphthalene-ds,
acenaphthene-dio, phenanthrene-dio, chrysene-di2, and perylene-di2 (Semivolatile Internal
Standard Mix, 2000 (ig/mL, P/N 861238, Supelco, Bellefonte, PA).
8.4 CWAs (GB, GD, GF, HD, VX, and VX-dw) were synthesized at LLNL and were used to
make a 10 (ig/mL solution in DCM. Spiking solutions were made from neat agent in
A-13
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dichloromethane. The purities of the neat agents were determined by nuclear magnetic
resonance spectroscopy (NMR) to be 95%, 95%, 95%, 99%, 96%, and 98% for GB, GD,
GF, HD, VX, and VX-di4, respectively.
8.5 Dilute all standards to an appropriate concentration in dichloromethane before use. CWA
standards are available to the Environmental Response Laboratory Network (ERLN) labs
as solutions of 10 (ig/mL each CWA in dichloromethane, sealed in 1-mL ampoules.
Surrogates and internal standards may be diluted in quantities that are needed. Specific
solutions needed include:
8.5.1 10 (ig/mL mixed CWA solution (includes GB, GD, GF, and HD)
8.5.2 10 (ig/mL VX solution
8.5.3 100 (ig/mL surrogate solution (included nitrobenzene-ds, 2-
fluorobiphenyl, terphenyl-di4, and phencyclidine-ds)
8.5.4 100 (ig/mL internal standard solution
8.5.5 10 (ig/mL VX-d 14 solution (if available)
8.6 The above solutions may be diluted with dichloromethane (DCM) to make 1-mL aliquots
of calibration standards, to be used for instrument calibration, as described in the table
below.
Calibration Standards and Concentrations in DCM
Calibration
Level
fiL
10 jig/mL
CWA mix
fiL
10 jig/mL
VX
fiL
100 fig/mL
surrogate mix
fiL
100 jig/mL
internal
standard mix
fiL
10 jig/mL
VX-di4
fiL
DCM
1
10
10
1
10
10
959
2
20
20
2
10
20
928
3
40
40
4
10
40
866
4
80
80
8
10
80
742
5
100
100
10
10
100
680
6
200
200
20
10
200
370
9.0 Sample Collection, Extraction, and Storage
Preparation of Control Samples
This section describes preparation of coupons for wipe sampling as well as the preparation of control wipe
samples. If this procedure is being used to measure CWA on collected wipes only, skip preparation of
samples described in Sections 9.1 - 9.3 and proceed directly to Section 9.4.
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9.1 Preparation of large coupons (equivalent surface coverage of 0.1 fig/cnr).
Spike large coupons of various materials (10 cm x 10 cm) using fifty 20-f.iL drops of a
solution containing 10 (ig/mL each CWA in DCM (total spike amount was 10 jj.g each
CWA). The drops of solution are spread evenly over the surface (see Figure A-3). Allow
the DCM solvent to evaporate for approximately 5 minutes prior to wipe sampling.
9.2 Preparation of small coupons (equivalent surface coverage of 0.1 ug/cnr).
Spike small coupons of various materials (area of approximately 10 cm2) using five 20-j^iL
drops of a solution containing 10 (ig/mL each CWA in DCM (total spike amount was 1 |_ig
each CWA). The drops of solution are spread evenly over the surface (see Figure A-3).
Allow the DCM solvent to evaporate for approximately 5 minutes prior to wipe sampling.
9.3 Wipe sampling of prepared coupons.
Saturate each wipe with solvent prior to sampling. The Kendall-Curity® wipes were
saturated with 5 mL of solvent and the smaller Dukal™ wipes were saturated with 1.5 mL
of solvent (either DCM or IP A). The solvent volume was enough to saturate the wipe
material without leaving it (or the surface being sampled) dripping wet. Fold each wipe
and hold with forceps prior to wiping the surface (NOTE: Depending on the size of the
wipe being used (Figure A-l), more than one fold may be needed. The laboratory should
use their best judgement to ensure that pre-determined size and folds are adequate to obtain
the data quality objectives. The Dukal™ wipes were folded twice and the Kendall-Curity®
wipes were folded four times). Wipe the surface, using a steady pressure, in a "Z" pattern
- first in the horizontal direction and then in a vertical direction, with a clean wipe surface
being exposed each time. After the first pass in the horizontal direction, invert the wipe and
wipe in the vertical direction (Figure A-7).
9.4 Preparation of control wipes
Directly spike wipes with 100 |_iL of a solution containing 10 |_ig/m L each CWA in DCM
(total spike amount was 1 |_ig each CWA). Directly extract the prepared wipes in DCM
(Section 9.5).
9.5 Extraction Procedure
9.5.1 Place wipe into a 40-mL VOA vial for extraction.
Spike with surrogate standards:
9.5.1.1 For small coupons, spike 10 (iL of a surrogate solution with each
component at 100 (iL/mL onto the wipe. This is the recommended
surrogate spike amount when analyzing environmental samples.
9.5.1.2 For large coupons were used, spike 100 |_iL of a surrogate solution with
each component at 100 |_iL/mL onto the wipe.
9.5.2 Add 15.00 mL of DCM to each VOA vial containing a wipe.
9.5.3 Place vials on shaker table (horizontal orientation). Extract for 15 minutes at 600
rpm.
A-l 5
-------
9.5.4 Transfer sample extracts to clean, 40-mL VOA vials and carefully rinse the
original vials with DCM.
9.5.5 Add another 15.00-mL aliquot (total volume) of DCM to each vial containing a
wipe.
9.5.6 Extract for 15 minutes at 600 rpm on the shaker table.
9.5.7 Combine resulting sample extract with previously collected aliquot.
9.5.8 Concentrate sample extract using clean nitrogen. A RapidVap unit (70% speed, 30
°C, N2 pressure of 12-15 psi) was used to bring the sample extract to a volume of
approximately 1 mL. Transfer the sample extract to an autosampler vial and reduce
to a final concentration volume of 1.0 mL (using a gentle stream of N2, no heat,
with the Reacti-Therm unit).
9.5.9 Add internal standard solution; 10 |_iL of a solution containing 100 ng/|_iL each
internal standard.
9.5.10 Analyze extracts by GC/MS.
9.6 Sample Storage
9.6.1 Store wipe samples in VOA vials in DCM solvent under refrigerated conditions
(Section 14.2). Sample stability on wipes is listed in Tables A-12 and A-14.
10.0 Quality Control
10.1 QC requirements include the performance of an initial demonstration of capability (IDC)
and ongoing quality control (QC) requirements that must be met to generate data of acceptable
quality when preparing and analyzing samples. This section describes the QC parameters, their
required frequencies and performance criteria.
10.2 INITIAL DEMONSTRATION OF CAPABILITY
The IDC must be performed successfully prior to the initiation of analysis of field samples.
Prior to conducting an IDC, an acceptable initial calibration must be generated.
10.2.1 INITIAL DEMONSTRATION OF LOW SYSTEM BACKGROUND
Any time new solvents, reagents, filters and autosampler vials are used, the LMB
must be demonstrated to be free of contamination. The LMB is used to ensure that
analytes of interest or other interferences are not present in the laboratory
environment, the solvent, or the apparatus.
A-16
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NOTE: Good laboratory practices indicate the use of solvent and procedure blanks before
and after analyzing a calibration curve for an instrument to ensure that no carryover
will occur. If the required criteria (as noted within each laboratory's QC protocol)
are not met and samples were not free of contamination, then the source of the
contamination should be identified and eliminated before the performance of any
analysis.
10.2.2 MINIMUM REPORTING LEVEL (MRL)
Establish a target concentration for the MRL based on the intended use of the
method. Establish an Initial Calibration. The lowest CAL standard used to establish
the initial calibration must be at or below the MRL concentration. If the MRL
concentration is too low, ongoing QC requirements may fail repeatedly, and the
MRL must be determined again at a higher concentration. The MRL reported
in this study is the lowest calibration level.
10.2.3 CONTINUING CALIBRATION VERIFICATION (CCV)
The CCV is used to check the continued validity of the initial calibration. The CCV
is a mid-range calibration standard and the acceptance criterion is ±35% of the
expected value(s) for all analytes. If the CCV does not meet the acceptance criteria,
it may be reanalyzed. If after reanalysis the ±35% criteria for the CCV are not met,
a new calibration curve must be made and used. The CCVs consist of clean solvent
that is fortified with a specific concentration of CWA (1 (ig/mL each agent). A
CCV check should be done at a minimum frequency of once every 8 hours;
preferably after every 10 field samples.
10.3 METHOD DETECTION LIMIT (MDL)
The procedure for the determination of the laboratory detection and quantitation limits for
the EPA approach follows 40 CFR Part 136, Appendix B. MDLs represent the minimum
concentration at which there is a high degree of statistical confidence that, when the
method reports that an analyte is present, that analyte is actually present (i.e., a low risk
of false positives). MDLs were not calculated in this procedure because they were already
calculated as described in the previous method (2).
10.4 ONGOING QC REQUIREMENTS
10.4.1 LABORATORY METHOD BLANK (LMB)
Method blanks are used to determine the background of each particular matrix. An
LMB is prepared and analyzed with each extraction batch for confirmation that
there are no background contaminants interfering with the identification or
quantitation of the target analytes. If there is a contaminant within the retention
time window preventing the determination of the target analyte, the source of the
contamination should be determined and eliminated before processing samples.
A-17
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The method blanks undergo the same extraction procedure as authentic samples
and are spiked with the surrogate standard; however, the method blanks do not
contain the target CWA analyte. One method blank is prepared for each set of
samples. The maximum number of samples in a set is 20.
10.4.2 CONTINUING CALIBRATION VERIFICATION CHECK
A CCV check should be performed at a minimum frequency of once every 8 hours;
preferably after every 10 field samples. CCVs should be within ±35% of the
expected value(s) for all analytes for the data to be considered valid. CCV values
should be specified by the sample submitter's data quality objectives or fulfill other
QC requirements.
10.4.3 MATRIX SPIKE/LABORATORY FORTIFIED MATRIX SPIKE (LFMS)
A LFMS is analyzed to determine that spike accuracy for a particular sample
matrix is not adversely affected by chemical interactions between target analytes
and experimental matrix. If a variety of sample matrices are analyzed, performance
should be established for each matrix or sample type.
10.4.3.1 When performing sample analyses, it is expected that LFMS and
LFMSD samples will be analyzed. LFMS/LFMSDs are representative
analyte-free environmental matrices that have been fortified with CWA.
These samples are taken through the extraction process to show that the
method is capable of detecting the analytes of interest in the relevant
matrices. LFMS and LFMSD samples should be prepared for each type of
matrix. Records are maintained of the target compound spike analyses, and
the average percent recovery (X) and the standard deviation (SD) are
calculated. Analyte recoveries may exhibit bias for certain matrices.
Acceptable recoveries are 50-150% if a low-level concentration near or at
the MRL (within a factor of 3) is used. If the recovery does not fall within
this range, check with a CCV or prepare a fresh AS solution for analysis.
If the recovery of any analyte still falls outside the designated range and
the laboratory performance for that analyte is shown to be in control in the
CCVs, the recovery is judged to be matrix-biased. The result for that
analyte in the unfortified sample is labeled suspect/matrix to inform the
data user that the results are suspect due to matrix effects.
10.4.4 SURROGATE STANDARD
All samples (CCVs, LMBs, LFMSs, LFMSDs, and CAL standards) are spiked
with surrogate standard spiking solution. An average percent recovery of the
surrogate compound and the standard deviation of the percent recovery are
calculated and updated regularly.
A-18
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11.0 Instrument Calibration and Standardization
All laboratory equipment should be tuned and calibrated according to manufacturer's protocols.
Demonstration and documentation of acceptable mass spectrometer (MS) tuning and initial calibration is
necessary prior to sample analysis. Verification of the tuning of the MS must be repeated each time
instrument modification/maintenance is performed and prior to analyte calibration. After initial calibration
is successful, a CCV should be performed at the beginning and end of each analysis batch.
11.1 INITIAL CALIBRATION FOR ANALYTES
11.1.1 Tune and calibrate using the manufacturer's algorithm. When implementing GC/MS
method, ensure that there are at least 10 scans across each peak for optimal precision.
GC/MS parameters utilized during development of this procedure are presented in
Section 12.3.4.
11.1.2 Establish GC operating conditions that will optimize peak resolution and shape.
Suggested GC conditions (listed in Section 12.3.4) may not be optimal for all GC
systems.
11.1.3 The initial calibration contains a six-point curve using the analyte concentrations
prepared (Section 9.6) (NOTE: The highest concentration of the calibration curve will
need to be lowered when analyzing CWA standards in other laboratory settings.
Laboratories will be limited by the ability to accept CWA standards at concentrations
greater than 10 (ig/mL so as to protect worker safety.) The lowest calibration curve
standard is at the MRL. The calibration curve and all samples should be analyzed in a
low to high concentration regimen so carryover is less of a concern in case the GC
thermal cycling does not clean the system adequately between injections. Verify that
all analytes have been properly identified and quantified using software programs
(Section 12.3.3). Integrate manually, if necessary, in accordance with laboratory
quality assurance plans. Depending on the instrument, sensitivity and calibration curve
responses may vary. If the polynomial type excludes the point of origin, use a fit
weighting of 1/X to give more weighting to the lower concentrations. The coefficient
of determination (r2) of the linear fit should be greater than or equal to 0.98. If one of
the calibration standards other than the high or low standard causes the r2 to be <0.98,
this point must be re-injected or a new calibration curve must be analyzed. The r2 of
the quadratic curve should be greater than or equal to 0.99. If one of the calibration
standards other than the high or low standards causes the r2 to be <0.99, follow the
same procedure given above for a linear fit. A calibration curve and an instrument
blank will be analyzed at the beginning of each batch or daily to ensure instrument
stability. When quantitated, each calibration point for each analyte should calculate to
be within 70-130% of its true value. The lowest CAL standard should calculate to be
within 50-150% of its true value. A new curve will be generated daily. The calibration
method is used to quantify all samples.
A-19
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11.2 QUANTITATION OF ANALYTES
The quantitation of the target analytes is accomplished with quantitation software as it relates
to each specific instrument (Section 12.3.3.). The data was collected with the Agilent
Chemstation software, which was used for quantification. Peak areas associated for each
analyte were compared to those of calibration standards. Because deuterated VX (VX-di4)
was synthesized and available for use, VX concentrations were quantitated using the
isotopically-labeled VX as well. A calibration range of 0.1/0.2- 1.0/2.0 (ig/mL is suggested
(note that the mixed CWA standard currently shipped to ERLN laboratories contains 5 (ig/mL
each GD and HD and 10 (ig/mL each GB and GF, which impacts the composition of the
calibration curve). Refer to the table (Section 13.1) for the quantitation and qualifying ions
and retention times utilized for this procedure.
12.0 Analytical Procedure
12.1 SAMPLE PREPARATION
12.1.1 Samples were collected and stored as described in Section 9. The surrogates are
added first, then the DCM solvent is added to the VOA vial.
12.1.2 After extraction, transfer resulting sample extract (via pipette) to a standard, 2-mL
autosampler vial.
NOTE: Calibration standards are not filtered.
12.2 SAMPLE ANALYSIS/ANALYTICAL SEQUENCE
12.2.1 Use the same Gas Chromatography/Mass Spectrometry conditions established per
guidance described below.
12.2.2 Prepare an analytical batch that includes all QC samples and field samples. The
first sample to be analyzed is a 1 jxL injection of a blank solvent on column
followed by the calibration curve.
12.2.3 Update the calibration file and print a calibration report. Review the report for
calibration outliers and make area corrections by manual integration, if necessary
and appropriate. If corrections have been made, update the calibration file, noting
the changes, and regenerate a calibration report. Alternatively, re-analyze
"nonconforming" calibration level(s) and repeat the above procedures.
12.2.4 The first sample analyzed after the calibration curve is an additional blank to
ensure there is no carryover. If the initial calibration data are acceptable, begin
analyzing samples, including QC and blank samples, at their appropriate frequency
injecting the same size aliquots (1 |o,L) under the same conditions used to analyze
CAL standards. The ending CCV must have each analyte concentration within
35% of the calculated true concentration or the affected analytes from that run must
A-20
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be qualified as estimates or the samples must be re-analyzed with passing criteria
to remove the qualification.
12.2.5 If the absolute amount of a target compound exceeds the working range of the GC-
MS system, the prepared sample is diluted with DCM solvent and re-analyzed
along with additional samples that may have run after the sample known to exceed
the calibration range, because of the possibility of carryover. Care must be taken
to ensure that there is no carryover of the analyte that has exceeded the calibration
range. If the amount of analyte exceeds the calibration range, a blank sample
should be analyzed afterward to demonstrate no carryover will occur.
12.2.6 At the conclusion of the data acquisition, use the same software that is used in the
calibration procedure to identify peaks of interest from the predetermined retention
time windows. Use the data software to examine the ion abundances of the peaks
in the chromatogram to identify and compare retention times in the sample
chromatogram with the retention time of the corresponding analyte peak in an
analyte standard.
12.3 CALIBRATION STANDARDS AND GC/MS INSTRUMENT CONDITIONS
12.3.1 Quantification was based on a six-point calibration curve using CWA standards at
0.1, 0.2, 0.4, 0.8, 1, and 2 ng/(iL each agent.
12.3.2 Instrument model and serial number: Agilent 5975C, US 10204302
12.3.3 Instrument software/software version: MSD ChemStation G1701EA,
E.02.02.1431
12.3.4 Instrumental conditions:
GC conditions:
Carrier gas:
Flow control/rate:
Injection mode:
Helium
0.8 mL/min
Pulsed splitless (25 psi until 0.5 min, 40 mL/min
purge flow to split vent at 0.51 min)
1 (iL
250 °C
Agilent, HP-5MS UI
30 m x 0.25 mm x 0.25 (im
40 °C (3 min) - 8 °C/min - 300 °C (3 min)
Injection volume:
Inj ector temperature:
Column brand/phase:
Column Length x ID x Film thickness:
GC temperature program:
MS conditions:
Source temperature:
Transfer line temperature:
250 °C
280 °C
A-21
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Solvent delay time:
• Ionization mode:
Mass resolution:
Scan range/time:
3 min
electron ionization, 70 eV
unit
29-600 m/z in 0.4 sec
13.0 Data Analysis and Calculations
13 .1 QUALITATIVE AND QUANTITATIVE ANALYSIS
13.1.1 Data is acquired by full-scan mass spectrometry. An external calibration is made
by considering the quantification ions for each CWA analyte. Quantitation
software is utilized to conduct the quantitation of the target analytes and surrogate
standards. The ions of each analyte are used for quantitation and confirmation.
Furthermore, VX-di4 was used as an extracted internal standard for VX analysis.
CWA Mass Spectrometry
on Transitions and Retention Times
Analyte
Quant. Ion
(m/z)
Qual. Ions (primary)
(m/z)
Qual. Ions (secondary)
(m/z)
Retention Time (min)
conditions in §12.3.4
GB
99
125
81
6.35
GD, peak 1
99
126
82
11.01
GD, peak 2
99
126
82
11.10
HD
109
158
63
13.66
GF
99
67
81
14.20
VX-di4
128
80
141
21.99
VX
114
72
127
22.12
13.1.2 Computer programs used for analysis of data include instrumentation and
quantitation software. Manual integration may be necessary for some peak areas if
the peak area is not integrated properly (i.e., the integration for the peak is not fully
performed by the instrument's software, which will be noticeable by visual
inspection of each peak). Inspect all integrated peaks for visible integration errors
and manually integrate as necessary to ensure consistent integration of other peaks
and/or known calibration peaks. Any manual integration should be carried out by
a qualified analyst, noted, and checked against quality control procedures.
13.2 Prior to reporting data, the chromatogram should be reviewed for any incorrect
peak identifications. The retention time window of the CWA transitions must be
within 5% of the retention time of the analyte standard. If this is not true, the
calibration curve needs to be re-analyzed to see if there was a shift in retention
times during the analysis and the sample needs to be re-injected. If the retention
time is still incorrect in the sample, the analyte is referred to as an unknown. If
peaks need to be manually adjusted due to incorrect integration by the program,
clarification of where professional judgment was used to alter the peaks should be
A-22
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documented during the data reduction and verification process.
14.0 Method Performance
14.1 RECOVERIES AND PRECISION FOR MATRIX TYPES
14.1.1 Section 18 lists recoveries and precision of target analytes for all tested
matrices.
14.2 STORAGE STABILITY STUDY
14.2.1 Spike CWAs on the wetted wipes (IPA or DCM) and store in closed VOA
vials under refrigeration (2-4 °C). Analyze samples on Days 0, 2, 7, 14 to
determine the stability of the analytes during the course of fourteen-day
storage. CWAs spiked on DCM-wetted (0.5 mL) Dukal™ wipes were at
two different concentrations (1 |_ig and 0.1 (.ig). (NOTE: A holding time
study was previously performed using CWA on the Kendall-Curity® wipe
(3) and compared over the fourteen day study for the two tested wipes
(Tables A-12 and A-14)).
15.0 Pollution Prevention
15.1 This method utilizes small volumes of organic solvent and small quantities of analytes,
thereby minimizing the potential hazards to both analyst and environment. Nevertheless,
proper procedures for handling and disposing hazardous analytes should be described for
each laboratory's health and safety and waste management plans.
15.2 For information about pollution prevention that may be applicable to laboratory operations,
consult "Less is Better: Laboratory Chemical Management for Waste Reduction" available
from the American Chemical Society's Department of Government Relations and Science
Policy, 1155 16th Street N.W., Washington, D.C., 20036 or on-line at
http://www.acs.org/content/dam/acsorg/about/governance/committees/
chemical safetv/publications/less-is-better.pdf (accessed August 15, 2013).
16.0 Waste Management
The analytical procedures described within generate relatively small amounts of waste since only small
amounts of reagents and solvents are used. Laboratory waste management practices must be conducted
consistent with all applicable rules and regulations, and laboratories should protect the air, water, and land
by minimizing and controlling all releases from fume hoods and bench operations. Also, compliance with
any sewage discharge permits and regulations is required, particularly the hazardous waste identification
rules and land disposal restrictions.
A-23
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Each laboratory should determine with federal and local officials how to safely dispose of
field and QC samples. Waste containers should be properly labeled to identify the contents.
Remember to attach the appropriate chemical waste label, date the beginning of collection
before using the container and follow all appropriate federal and local waste disposal
requirements.
A-24
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17.0 References
1) Sampling of Common Pesticides and PCBs from Inert Surfaces, EPA/330/1-90-001,
October 1989, prepared by B. L. Carr and D. F. Hill, National Enforcement
Investigations Center, Denver, CO. Washington DC: Office of Enforcement and
Compliance Testing, U.S. Environmental Protection Agency.
2) U.S. Environmental Protection Agency (EPA), 2012. Selected Analytical Methods for
Environmental Restoration Following Homeland Security Events (SAM). EPA/600/R-
12/555 July 2012. Cincinnati, Ohio: United States Environmental Protection Agency,
Office of Research and Development, National Homeland Security Research Center
3) Chemical Warfare Agents Wipe Sampling Collection Efficiencies and Holding Time
Studies, LLNL-TR-450992, Lawrence Livermore National Laboratory, August 2010.
4) Verification of Methods for Selected Chemical Warfare Agents (CWAs), January 2013,
U.S. Environmental Protection Agency, EPA/600/R-12/653
5) 3M Window Film FAQs, Accessed January 4, 2016, URL
http://soliitions.3m.com/wps/portal/3M/en US/Window Film/Solutions/Resoiirces/Reso
urces List/FAQs/.
A-25
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18.0 Tables, Figures, and Validation Data
List of Tables
Table A-l. Wipe contaminants tentatively identified by GC/MS A-27
Table A-2. Average recoveries (%) for CWA, pesticides, and surrogates from drywall A-27
Table A-3. Statistical analyses of drywall recoveries A-27
Table A-4. Average recoveries (%) for CWA, pesticides, and surrogates from vinyl tile A-28
Table A-5. Statistical analyses of vinyl tile recoveries A-28
Table A-6. Average recoveries (%) for CWA, pesticides, and surrogates from laminate A-29
Table A-7. Statistical analyses of laminate recoveries A-29
Table A-8. Average recoveries (%) for CWA, pesticides, and surrogates from coated glass A-30
Table A-9. Statistical analyses of coated glass recoveries A-30
Table A-10. Average recoveries (%) for CWA, pesticides, and surrogates from wood A-31
Table A-l 1. Statistical analyses of recoveries comparing direct extraction with wipe extraction (small
coupons only) A-3 2
Table A-12. Holding time study data, 1 (ig each CWA on wipes A-33
Table A-13. Statistical analysis of holding time study data, 1 |_ig each CWA on Dukal™ wipes A-33
Table A-14. Holding time study data, 0.1 (ig each CWA on wipes A-33
Table A-15. Statistical analysis of holding time study data, 0.1 |_ig each CWA on Dukal™ wipes A-34
Table A-16. Average recoveries (%) for VX, from various matrices, with and without consideration of
di4-VX extracted internal standard A-34
List of Figures
Figure A-l. Example spiking patterns for 10-cm2 and 100-cm2 coupons A-12
Figure A-2. Kendall-Curity® wipe (left) and Dukal™ wipe (right) A-35
Figure A-3. Materials tested in this study A-3 6
Figure A-4. TICs for wipes that were received, extracted, and analyzed by GC/MS A-l 1
Figure A-5. TICs for method blank and Dukal wipes pre-cleaned and "as received" A-37
Figure A-6. TICs for method blank and Kendall-Curity wipes pre-cleaned and "as received" A-37
Figure A-7. Example of wiping pattern for each tested surface spiked with target analytes A-40
A-26
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A-27
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Table A-l. Wipe Contaminants Tentatively Identified by GC/MS; Peaks Numbers Correspond to
Those Listed in Figures A-4
Peak
Tentative Identification
Retention Time (min)
Reverse Fit
1
2-(2-ethyoxyethyoxy)ethanol
10.39
967
2
2,4-di-tert-butylphenol
19.62
884
3
butylated hydroxytoluene
19.68
920
4
n-hexadecane
20.85
962
5
n-heptadecane
22.28
924
6
n-octadecane
23.63
943
7
n-hexadecanoic acid
25.73
930
8
n-eicosane
26.13
920
9
n-tricosane
29.50
909
10
n-tetracosane
30.53
959
11
n-pentacosane
31.54
907
12
di-n-octyl phthalate
32.09
856
13
n-hexacosane
32.50
909
14
n-heptacosane
33.41
890
15
n-octacosane
34.30
916
16
n-nonacosane
35.16
887
17
Surfynol 104
18.08
876
18
tributylphosphate
21.61
959
19
Uniplex 108
21.84
869
20
pentadecanal
22.51
915
21
dibutylphthalate
25.78
953
22
docosane
28.43
946
A-28
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Table A-2. Average" Recoveries (%) for CWA, Pesticides, and Surrogates from Painted Drywall
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
57 ±6
15 ± 12
ND
10 ±3
6 ± 1 b
8 ± 4 b
4 ± 4 b
ND
10 ±0
GD
114± 19
30 ±26
24 ±6
11 ± 3
13 ±4
18 ±4
15 ± 1
ND
11 ± 1
HD
82 ± 14
13 ± 7
11 ± 3
10 ±2
8 ± 1 b
8 ± 3 b
9 ± 1 b
ND
8 ± 0 b
GF
115 ±20
40 ±20
24 ±4
5 ± 3 b
19 ±3
27 ±7
21 ± 1
ND
5 ± 0 b
VX
94 ±20
62 ± 17
41 ± 7
8 ± 1 b
27 ±3
48 ±29
45 ±4
ND
11 ± 3
MA
127 ±9
55 ± 13
17 ± 16
4 ± 1 b
9 ± 7 b
41 ± 7
17 ±2
ND
ND
DZN
84 ± 12
41 ± 19
18 ±5
6 ± 1 b
12 ±3
29 ± 11
18 ±2
ND
ND
NB-ds
75 ±10
57 ±8
63 ±5
71 ±7
ND
74 ±9
39 ±3
81 ± 16
89 ±7
2-FB
69 ±4
56 ±9
79 ±5
78 ±8
140 ±0
70 ±9
83 ±2
74 ±5
91 ± 7
PCP-ds
84 ±9
88 ±9
86 ± 10
71 ±6
140 ± 1
113 ±8
101 ± 1
67 ±7
90 ±7
ter-di4
74 ±6
59 ±7
84 ±7
77 ±5
150 ±0
73 ± 11
87 ±3
72 ±6
90 ±6
small =10 cm2 coupon spiked with 1 |ig analyte; large = 100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine,
ter-di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements; b estimated average concentration was
below lowest calibration level
Table A-3. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table A-2)
from Drywall
Tested Variable(s)
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Wipe
0.48
0.10
0.54
0.025
0.19
0.16
0.16
Wetting Solvent
0.21
0.96
0.99
0.63
0.98
0.0008
0.087
Coupon Size
0.54
0.010
0.11
<0.0001
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent
0.030
0.70
0.30
0.91
0.84
0.56
0.41
Wipe +
Coupon Size
0.62
0.41
0.66
0.78
0.75
0.31
0.95
Wetting Solvent +
Coupon Size
0.20
0.31
0.80
0.021
0.32
<0.0001
0.0033
Wipe +
Wetting Solvent +
Coupon Size
0.96
0.98
0.96
0.057
0.12
0.27
0.29
Note: a p < 0.01 indicates statistical significance; statistically significant results are highlighted and in bold font.
A-29
-------
Table A-4. Average" Recoveries (%) for CWA, Pesticides, and Surrogates from Vinyl Tile
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
59 ±2
29 ±5
ND
9 ± 1b
ND
19 ± 1
ND
ND
ND
GD
107 ±6
72 ±2
ND
11 ±3
ND
60 ±4
7 ± 0b
ND
ND
HD
84 ±3
43 ± 1
ND
10 ±3
ND
29 ±3
ND
ND
ND
GF
114 ± 5
96 ±2
16 ±3
20 ±7
ND
81 ±4
12 ± 1
ND
ND
VX
ND
125 ±3
72 ±6
19± 11
27 ±7
134 ± 1
62 ± 11
14 ±2
15 ±4
MA
138 ±6
104 ±3
35 ±2
6 ± 3 b
ND
92 ±2
34 ± 1
ND
ND
DZN
111 ±5
84 ±5
23 ±2
13 ±6
ND
86 ± 1
22 ± 1
ND
ND
NB-ds
78 ±6
56 ±2
73 ±9
74 ±6
76 ±6
88± 11
44 ±4
117 ± 8
91 ±2
2-FB
65 ±4
44 ±2
87 ±4
78 ±5
141 ± 1
78 ±8
92 ± 10
119 ± 4
88 ±2
PCP- ds
41 ±4
75 ±2
99 ±3
76 ±6
125 ± 1
86 ±5
109 ±0
106 ±3
100 ±6
ter-di4
53 ±3
51 ±3
100 ±4
81 ±7
151 ± 1
88 ±7
95 ±10
131 ± 4
104 ±6
small =10 cm2 coupon spiked with 1 |ig analyte; large =100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine, ter-
di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements;b estimated average concentration was below
lowest calibration level
Table A-5. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table A-4)
from Vinyl Tile
Tested Variable(s)
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Wipe
0.002(»
o.ooss
0.00S2
0.0002
<)<>:i
llll-
0.0003
Wetting Solvent
II. 1
1 I.I IIIIII
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
Coupon Size
<11. Ill IIII
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent
-0.0001
0.0031
0.0002
0.0003
0.0043
(1 <)-
0.0024
Wipe +
Coupon Size
<0.0001
0 4(1
u 5:
U I I
(1 <>u
1
<0.0001
Wetting Solvent +
Coupon Size
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent +
Coupon Size
0.17
0.091
0.10
0.48
0.83
0.62
0.023
Note: a p < 0.01 indicates statistical significance; statistically significant results are highlighted and in bold font.
A-30
-------
Table A-6. Average" Recoveries (%) for CWA, Pesticides, and Surrogates from Laminate
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
10 ±2
ND
ND
ND
ND
ND
ND
ND
ND
GD
14 ±5
ND
ND
ND
ND
ND
ND
ND
ND
HD
14 ±4
ND
ND
ND
ND
ND
ND
ND
ND
GF
26 ±7
ND
ND
ND
ND
ND
ND
ND
ND
VX
50 ± 12
38 ±8
41 ± 18
31 ±2
37 ±6
51 ±6
25 ± 20 c
30 ±4
26 ± 6
MA
100 ± 17
80 ± 18
66 ±26
69 ±5
71 ± 7
69 ±2
59 ±20
71 ±9
50 ± 1
DZN
74 ± 10
51 ± 7
39 ± 12
45 ± 1
44 ±4
43 ±7
33 ±9
47 ±6
38 ± 5
NB-ds
ND
93 ±4
60 ±8
87 ±3
95 ±7
77 ±34°
39 ±2
87 ± 10
100 ±3
2-FB
6 ± 5 b
84 ±3
60 ±7
84 ±5
89 ±3
73 ±7
70 ± 1
87 ±9
94 ±3
PCP- ds
60 ± 10
85 ±2
76 ±4
72 ±3
88 ±3
84 ± 6
80 ±3
82 ±9
96 ±3
ter-di4
104 ± 16
99 ±3
81 ± 4
85 ±7
93 ±6
92 ±5
83 ±4
89 ±8
94 ±2
small =10 cm2 coupon spiked with 1 |ig analyte; large =100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine, ter-
di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements;b estimated concentration was below lowest
calibration level; 0 one of the three recoveries was noticeably lower than the others
Table A-7. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table A-6)
from Laminate
Tested Variable(s)
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Wipe
0.44
0.18
0.13
Wetting Solvent
0.26
0.13
0.014
Coupon Size
0.10
0.64
0.51
Wipe +
Wetting Solvent
Too few
detections
for
statistical
analysis
Too few
detections
for
statistical
analysis
Too few
detections
for
statistical
analysis
Too few
detections
for
statistical
analysis
0.047
0.49
0.59
Wipe +
Coupon Size
0.66
0.95
0.51
Wetting Solvent +
Coupon Size
0.17
0.84
0.32
Wipe +
Wetting Solvent +
0.34
0.34
0.41
Coupon Size
Note: a p < 0.01 indicates statistical significance; statistically significant results are in highlighted font.
A-31
-------
Table A-8. Average" Recoveries (%) for CWA, Pesticides, and Surrogates from Coated Glass
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
ND
ND
ND
ND
ND
ND
ND
ND
ND
GD
ND
ND
ND
ND
ND
ND
ND
ND
ND
HD
20 ±4
3b'°
ND
9 ± lb
ND
ND
ND
3 b'°
ND
GF
16 ±2
15 ± 2
13 ±0
25 ±4
19 ± 6
ND
ND
21 ±7
15 ± 1
VX
51 ±7
63 ± 10
96 ± 16
83 ±6
70 ±8
69 ± 10
102 ± 17
81 ±9
36 ±6
MA
104 ±5
92 ±4
109 ±9
101 ±5
49 ±8
102 ± 12
107 ± 15
92 ±7
28 ± 10
DI
71 ± 13
76 ±4
71 ± 13
92 ±4
52 ±7
77 ±9
85 ± 15
87 ±6
38 ±4
NB-ds
20 ±7
76 ±4
61 ± 1
95 ±4
66 ±8
91 ±7
71 ± 17
92 ±3
83 ±3
2-FB
16 ±3
70 ±3
69 ±3
85 ±3
136 ±2
78 ±6
78 ± 10
86 ±2
77 ±4
PCP- ds
69 ±7
72 ± 1
84 ± 1
82 ±2
108 ± 1
82 ± 10
95 ± 11
88 ±3
79 ±4
ter-dw
82 ±8
78 ±2
83 ±5
90 ±2
117 ± 1
90 ±9
90 ± 1
91 ±4
74 ±4
small =10 cm2 coupon spiked with 1 |ig analyte; large =100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine, ter-
di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements;b estimated concentration was below lowest
calibration level; 0 two of three measurements were "non-detects"
Table A-9. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries (Table A-8)
from Coated Glass
Variable(s) Tested
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Wipe
0.011
0.19
0.15
0.75
Wetting Solvent
0.025
0.66
<0.0001
<0.0001
Coupon Size
0.0003
0.0038
<0.0001
0.010
Wipe +
Wetting Solvent
Too few
detections
for
statistical
analysis
Too few
detections
for
statistical
analysis
Too few
detections
for
statistical
analysis
0.39
0.10
0.13
0.79
Wipe +
Coupon Size
0.047
0.017
0.022
0.32
Wetting Solvent +
Coupon Size
0.11
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent +
0.62
0.099
0.97
0.16
Coupon Size
Note: a p < 0.01 indicates statistical significance; statistically significant results are highlighted and in bold font.
A-32
-------
Table A-10. Average" Recoveries (%) for CWA, Pesticides, and Surrogatesb from Wood
Analyte
Direct
extraction
small
KC
DCM
small
KC
IPA
small
KC
DCM
large
KC
IPA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
GB
ND
ND
ND
ND
ND
ND
ND
ND
ND
GD
37 ±8
ND
ND
ND
ND
ND
ND
ND
ND
HD
33 ±6
ND
ND
ND
ND
ND
ND
ND
ND
GF
60 ± 13
ND
ND
ND
ND
ND
ND
ND
ND
VX
80 ±40
ND
58 ±8
ND
ND
ND
21 ± 8
ND
ND
MA
173 ± lc
17 ± 1
44 ± 11
ND
ND
ND
ND
ND
ND
DZN
130 ±7
14 ± 1
34 ±6
ND
ND
ND
ND
ND
ND
NB-ds
74 ±21
102 ±9
91 ± 1
91 ±3
ND
94 ±3
71 ± 8
100 ±5
99 ± 1
2-FB
34 ±7
92 ±3
98 ±2
90 ±3
100 ±6
90 ±5
118 ± 2
94 ±3
96 ± 1
ter-dw
88 ±6
119 ± 3
112 ± 2
84 ±2
101 ±7
101 ± 1
123 ±3
83 ± 1
89 ±2
small =10 cm2 coupon spiked with 1 |ig analyte; large =100 cm2 coupon spiked with 10 |ig analyte
Abbreviations: 2-FB = 2-fluorobiphenyl, DCM = dichloromethane, DZN = diazinon, IPA = isopropanol, KC = Kendall-
Curity wipe, MA = malathion, NB-ds = deuterated nitrobenzene, ND = non-detect, PCP- ds = deuterated phencyclidine, ter-
di4= deuterated terphenyl
Note: a average of three replicates ± the standard deviation of the measurements; b deuterated phencyclidine was not used in
this experiment; 0 interference noted
A-33
-------
Table A-ll. Statistical Analyses (ANOVA p-valuesa) of CWA and Pesticide Recoveries from Direct
Extraction and Wipe Extraction (Small Coupons Only)
Tested Variable(s)
per Matrix
ANOVA p-valuesa
GB
GD
HD
GF
VX
MA
DZN
Drywall
Wipe/Direct Extraction
i i.i ii ii II
0.44
<0.0001
<0.0001
0."
<0.0001
<0.0001
Wetting Solvent
0.19
0.75
0.94
0.22
0.4S
0.002"7
U.U32
Wipe +
Wetting Solvent
0.24
0.92
0.76
0.43
0.58
0.53
0.39
Vinyl Tile
Wipe/Direct Extraction
b
<0.0001
b
<0.0001
<0.0001
<0.0001
<0.0001
Wetting Solvent
<11.1 IIIIII
<0.0001
<0.0001
<0.0001
<0.0001
Wipe +
Wetting Solvent
0.0004
0.012
0.029
0.73
0.47
Laminate
Wipe/Direct Extraction
b
b
b
b
0.48
0.11
0.0007
Wetting Solvent
0.19
0.34
(1 <>(,<>
Wipe +
Wetting Solvent
0.12
0.89
0.88
Coated Glass
Wipe/Direct Extraction
b
b
b
b
0.010
0.77
0.42
Wetting Solvent
0.0012
0.086
0.81
Wipe +
Wetting Solvent
0.98
0.30
0.36
Wood
Wipe/Direct Extraction
b
b
b
b
b
b
b
Wetting Solvent
Wipe +
Wetting Solvent
Abbreviations: DZN = diazinon, MA = malathion
Notes: a p < 0.01 indicates statistical significance; statistically significant results highlighted and in bold font.
b indicates too few detections for statistical analysis
A-34
-------
Table A-12. Holding Time Study Data, 1 jig Each CWA on Wipes
TM
Dukal Wipe - measured CWA amount
Kendall-Curity® Wipe a — measured CWA amount
Day 0
Day 2
Day 7
Day 14
Day 0
Day 2
Day 7
Day 14
GB
1.07 ±0.04
1.07 ±0.07
0.97 ±0.05
1.12 ± 0.12
0.89 ±0.03
0.89 ±0.03
0.91 ±0.03
0.9 ±0.03
GD
1.51 ± 0.11
1.38 ± 0.11
1.51 ± 0.16
1.42 ±0.20
0.96 ±0.03
0.99 ±0.02
1.02 ±0.02
1.01 ±0.02
HD
1.11 ±0.06
1.16 ± 0.10
1.08 ±0.07
1.16 ± 0.13
0.94 ±0.04
0.81 ±0.02
0.92 ±0.02
0.82 ±0.04
GF
1.47 ± 0.13
1.27 ±0.10
1.26 ±0.14
1.50 ±0.17
1.08 ±0.06
1.15 ±0.05
1.16 ±0.02
1.18 ±0.03
VX
1.02 ±0.09
0.91 ±0.06
1.06 ±0.09
0.53 ±0.17
1.02 ±0.06
(t.38 ±0.03b
0.96 ±0.02
0.32 ± 0.03
Average amounts ± standard deviation of the measurements of CWA on three wipes, stored in a VOA vial under
refrigeration (2-4 °C) for 0, 2, 7, and 14 days after spiking on Day 0 with 1 |ig of each CWA.
a data from previous study (3); b cause of the low, 0.38 ng, amount of VX measured on the Kendall-Curity gauze on Day
2 in unknown; possible causes might be attributed to hydrolysis (e.g., water inadvertently introduced into the sample or
extraction solvent).
Table A-13. Statistical Analysis of Holding Time Study Data, 1 jig Each CWA on Dukal™ Wipes
p-valuesa from Dunnett's Test
1 fig each CWA on Dukal™ Wipe
Analyte
ti — to
h— to
tl4 to
GB
0.769
0.159
0.940
GD
0.319
0.740
0.436
HD
0.900
0.578
0.915
GF
0.123
0.113
0.842
VX
0.293
0.873
<0.001
Notes: a p-values for comparison of 2, 7, and 14-day time point amounts and the measured amount
at the start of the experiment (t=0); p-value < 0.01 indicates statistically significant concentration
decrease.
Table A-14. Holding Time Study Data, 0.1 jig Each CWA on Wipes
Dukal™ Wipe a
Kendall-Curity® Wipe b
Day 0
Day 2
Day 7
Day 14
Day 0
Day 2
Day 7
Day 14
GB
0.16 ±0.01
0.13 ±0.00
0.12 ±0.00
0.21 ±0.01
ND
ND
ND
ND
GD
0.11 ±0.01
0.08 ±0.01
0.10 ±0.01
0.13 ±0.01
0.11 ±0.01
0.12 ±0.01
0.14 ±0.01
0.15 ±0.01
HD
0.14 ±0.01
0.10 ±0.00
0.10 ±0.01
0.22 ±0.01
0.10 ±0.00
0.09 ±0.03
0.11±0.01
0.08 ±0.01
GF
0.25 ±0.10
0.19 ±0.00
0.19 ±0.03
0.12 ± 0.10
0.11±0.01
0.13 ±0.02
0.13 ±0.01
0.14± 0.00
VX
0.19 ±0.00
0.16 ±0.01
0.13 ± 0.01
ND
0.11±0.01
0.09 ±0.02
0.10 ±0.01
0.10± 0.06
a Average amounts ± standard deviation of the measurements of CWA on three wipes, stored in a VOA vial under
refrigeration (2-4 °C) for 0, 2, 7, and 14 days after spiking on Day 0 with 0.1 ng of each CWA; b data from previous
study (3)
A-35
-------
Table A-15. Statistical Analysis of Holding Time Study Data, 0.1 jig Each CWA on Dukal™ Wipes
p-valuesa from Dunnett's Test
0.1 fig each CWA on Dukal™ Wipe
Analyte
ti — to
h— to
tl4— to
GB
0.006
<0.001
1
GD
0.029
0.391
0.974
HD
0.001
0.001
1
GF
0.073
0.084
0.011
VX
0.221
0.021
<0.001
Notes: a p-values for comparison of 2, 7, and 14-day time point amounts and the measured amount
at the start of the experiment (t=0); p-value < 0.01 indicates statistically significant concentration
decrease.
Table A-16. Average11 Recoveries (%) for VX, from Various Matrices, With and Without
Consideration of VX-di4 Extracted Internal Standard (Listed as VX by IS).
Matrix
Direct
extraction
small
KC
DCM
small
KC
I PA
small
KC
DCM
large
KC
I PA
large
Dukal
DCM
small
Dukal
IPA
small
Dukal
DCM
large
Dukal
IPA
large
Drvwall
VX
94 ±20
62 ± 17
41 ± 7
8 ± 1b
27 ±3
48 ±29
45 ±4
ND
11 ±3
WbylS
90 ± 7 0
87 ±6
80 ±8
97 ±8
87 ±2
100 ±7
86 ±7
ND
85 ± 10
Yiin 1 lile
VX
ND
125 ^
o
19 11
"> _ _
134 1
bl 11
14_2
15 4
VXbylS
ND
118 ± 4
129 ±8
127 ±6
84 ± 1
114 ±5
150 ±9
94 ±2
106 ±9
Laminate
VX
50 ± 12
38 ±8
41 ± 18
31 ±2
37 ±6
51 ±6
25 ± 20 d
30 ±4
26 ±6
VXbylS
94 ±5
78 ± 13
64 ± 28 d
80 ±5
75 ±3
72 ± 15
50 ± 18 d
73 ±4
73 ±8
Coated Glass
VX
51 ±7
63 ± 10
96 ± 16
83 ±6
70 ±8
69 ± 10
102 ± 17
81 ±9
36 ±6
VXbylS
101 ±9
107 ±7
97 ±8
118 ± 2
87 ± 10
105 ±4
110 ± 4
116 ± 4
91 ± 10
Wood
VX
80 ±40
ND
58 ±8
ND
ND
ND
21 ± 8
ND
ND
VXbylS
82 ±3
57 ±6
57 ±5
ND
56 ±2
63 ±7
56 ±2
ND
ND
small=coupon of 10 cm2 surface area, large=coupon with 100 cm2 surface area
Abbreviations: DCM=dichloromethane, IPA=isopropanol, KC=Kendall-Curity wipe
Note: a average of three, independent replicates ± the standard deviation of the measurements; b estimated average
c d
concentration was below lowest calibration level; average of two values, potential outlier ignored; one of three
measurements markedly different from the others
A-36
-------
Gauze Sponges
KenoALL
x/uypScieritific
n Products
Figure A-1. Kendall-Curity® wipe (left) and Dukal' " wipe (right).
A-37
-------
Figure A-2. Materials tested in this study (100 cm2 and 10 cm2 coupons).
o o
0
o o
Figure A-3. Example spiking patterns for 10-cm2 and 100-cm2 coupons.
A-3 8
-------
12
1 4e+08 '
Dukal wipe, not precleaned
1 23 4 5 6 78
11
3 10 j
..II
13
14
| 1151^ ,
5.00
10.00
15.00
20.00
25.00
30.00
35.00
1.4e+Q8
Kendall Curity wipe, not precleaned
11
10
X
,i
17
13
14
5.00 10.00 15.00 20,00 25.00
Retention Time (min)
30.00
35.00
Figure A-4. TICs for wipes that were received, extracted, and analyzed by GC/MS.
Compounds were tentatively identified by library search and summarized in Table A-l.
2e+G8
, 4, ¦, >, i,
Method blank
2e+0B
¦ I. I,... i., l
¦..1 i,i... . , i
Dukal wipe, precleaned
2e+Q8
' »
Dukal wipe, as is
i_u
5 00 10 00 15.00 20.00 30.00 35.00
Retention Time (mm)
Figure A-5. TICs for method blank and Dukal wipes pre-cleaned and "as received".
A-39
-------
1.4e+08
Lf)
¦M
'c
—* 1.4e+08
>
i—
03
i_
¦M
JD
<
1.4e+08
Method blank
I
Kendall-Curity wipe, precleaned
l* | li L f t
rJ-
Kendall-Curity wipe, as is
I.
JL
5.00 10.00 15.00 20.00 25.00 30.00 35.00
Retention Time (min)
Figure A-6. TICs for method blank and Kendall-Curity wipes pre-cleaned and "as received".
Figure A-7. Example of wiping pattern for each tested surface spiked with target analytes.
A-40
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