Accepted Manuscript Title: Demonstration of Spread-on Peel-off Consumer Products for Sampling Surfaces Contaminated with Pesticides and Chemical Warfare Agent Signatures Author: Deborah L. Behringer Deborah L. Smith Vanessa R. Katona Alan T. Lewis Jr. Laura A. Hernon-Kenny Michael D. Crenshaw PII: DOI: Reference:

S0379-0738(14)00183-2 http://dx.doi.org/doi:10.1016/j.forsciint.2014.04.030 FSI 7589

To appear in:

FSI

Received date: Revised date: Accepted date:

21-1-2014 17-4-2014 25-4-2014

Please cite this article as: Deborah L.Behringer, Deborah L.Smith, Vanessa R.Katona, Alan T.Lewis, Laura A.Hernon-Kenny, Michael D.Crenshaw, Demonstration of Spread-on Peel-off Consumer Products for Sampling Surfaces Contaminated with Pesticides and Chemical Warfare Agent Signatures, Forensic Science International http://dx.doi.org/10.1016/j.forsciint.2014.04.030 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Demonstration of Spread-on Peel-off Consumer Products for Sampling Surfaces Contaminated with Pesticides and Chemical Warfare Agent Signatures Deborah L. Behringer, Deborah L. Smith, Vanessa R. Katona, Alan T. Lewis, Jr., Laura A. HernonKenny and Michael D. Crenshaw a,*[email protected] [email protected] a

* Corresponding author: Tel.: +1 614 424 3367; fax: +1 614 458 3367.

ip t

CBRNE Defense, Battelle Memorial Institute, 505 King Avenue, Columbus, Ohio 43201, USA

d

M

an

us

cr

Abstract A terrorist attack using toxic chemicals is an international concern. The utility of rubber cement and latex body paint as spray-on/spread-on peel-off collection media for signatures attributable to pesticides and chemical warfare agents from interior building and public transportation surfaces two weeks post-deposition is demonstrated. The efficacy of these media to sample escalator handrail, stainless steel, vinyl upholstery fabric, and wood flooring is demonstrated for two pesticides and eight chemicals related to chemical warfare agents. The chemicals tested are nicotine, parathion, atropine, diisopropyl methylphosphonate, dimethyl methylphosphonate, dipinacolyl methylphosphonate, ethyl methylphosphonic acid, isopropyl methylphosphonic acid, methylphosphonic acid, and thiodiglycol. Amounts of each chemical found are generally greatest when latex body paint is used. Analytes with low volatility and containing an alkaline nitrogen or a sulfur atom (e.g., nicotine and parathion) usually are recovered to a greater extent than the neutral phosphonate diesters and acidic phosphonic acids (e.g., dimethyl methylphosphonate and ethyl methylphosphonic acid).

Ac ce pt e

Keywords: Surface sampling, Chemical warfare agents, Pesticides, Latex body paint, Rubber cement, Building materials

1. Introduction 1.1 Basis for need Prevention and investigation of potential acts of terrorism has necessarily become a concern of all nations. Within the U.S.A., the Department of Homeland Security (DHS), Federal Bureau of Investigation (FBI), local law enforcement and first responders take on this responsibility. One of the concerns is an act in which indiscriminant mass chemical poisoning occurs in a crowded venue such as public buildings or transportation. An example of this type of attack is the sarin release in the Tokyo subway on 20 March 1995. When such an event occurs, sample collection for forensic analysis will include samples from surfaces suspected of being contaminated as well as from the victims. To this end, the ability to collect samples from potentially contaminated surfaces for subsequent analysis is required, not only to characterize the nature and extent of the poison but to link the attack to individuals and groups. In these situations, the degradation products and byproducts of the toxic substance are more useful for linking the perpetrators to the act. Chemical attribution signatures are defined by DHS as impurities, unreacted precursors, additives, byproducts, physical and chemical characteristics, and other anomalies that persist in a chemical agent or its degradation products that can be used for forensic purposes [1].

Page 1 of 26

During the Tokyo subway attack, the nerve agent sarin (agent GB) was released by puncturing one or two plastic bags and then allowing the sarin-containing mixture to evaporate. The plastic bags, each containing 600 to 900 mL, were concealed in newspaper, placed on the floor and punctured with the tip of an umbrella [2,3,4,5]. Once vaporized, much of the sarin is expected to be rapidly adsorbed by the surrounding surfaces [6].

d

M

an

us

cr

ip t

Data from chemical analysis of the residual sarin in the bags used in this attack has been reported (Table 1) [3]. Identified are the threat agent (sarin), reagent and solvent (N,Ndiethylaniline, hexane), byproducts (diisopropyl methylphosphonate, diisopropyl fluorophosphate), and degradation products (methylphosphonofluoridic acid, methylphosphonic acid, isopropyl methylphosphonic acid). Using this information along with the reported densities for each component, the maximum concentration in the air within a subway car would range from approximately 2.2 to 4.4 g/m3, depending on whether the content of one or two 600-mL bags was released [7,8,9,10]. These calculated air concentration values for sarin are well above the 100 mg-min/m3 LCt50 to an individual by inhalation [11]. If all of the agent released was evenly and equally adsorbed by the subway car interior walls and the total body surface area of the 150 to 300 passengers that may be present in the subway car at peak ridership times [12], the amount of sarin on the surfaces would range from about 31 to 98 µg/cm2. While these values are hypothetical, they do provide an estimate of the extent of contamination and amounts that may be available for sampling. Of course, the amount of sarin present in the air and on surfaces is expected to vary greatly. It will be much greater than the hypothetical amounts near the point of release and decrease as the distance from that point increases.

Ac ce pt e

1.2 Current methods and requirements Wipe samples are often used to collect pesticide residues and chemical warfare agent-related chemicals from surfaces to assess the extent of contamination [15,16,17]. Cotton gauze pads are most often used though cotton swabs, filter paper, cloth, and facial tissues also have been used. Wipes may be dry or wetted with a solvent when used to collect samples. Techniques using wipes suffer from short contact time and non-intimate contact with rough surfaces such that collection methods recommend against using wipe methods for rough or porous materials. Confounding the ability to thoroughly characterize a potentially contaminated vehicle or building is the fact that many common materials of construction are neither smooth nor nonporous. This situation results in the reduced ability to verify the presence of toxic chemicals from intentional contamination. This has led to the recommendation that either wipes not be used for sampling porous surfaces or that multiple wipe samples, each wetted with a different solvent, be used [18]. Needed is a convenient method for sampling irregular, non-horizontal, and porous surfaces for an extended duration such as that which may be accomplished using a sampling medium that adheres to the surface, then is peeled and extracted for analysis. This type of technique has been reported using spray booth and radiological decontamination materials (Floorpeel 4000, Vinol E15/45 VL and UCAR 451 UC) for the simultaneous sampling of eight liquid chemicals from glass immediately after contamination [19]. The potential advantages of using a peelable sampling medium include the ability to readily and non-destructively collect deposited vapors,

Page 2 of 26

mists and small particles over any size area while maintaining intimate contact between the surface and sampling medium for increased efficiency.

cr

ip t

Ideally, the sampling media should be safe and inexpensive to use with a long shelf-life and no special storage requirements. The sampling media and technique must be applicable to varying surface areas and for the collection of hundreds or thousands of samples. That is, the method for preparing the samples for analysis also must be as quick and simple as possible and not require a large amount of materials or labor. Commercial-off-the-shelf (COTS) materials were considered for fulfilling these requirements to avoid costly development efforts for designing and preparing new sampling media.

M

an

us

1.3 Preliminary tests To determine if some existing COTS products are suitable for collecting residual contaminants from materials commonly found in buildings and public transportation, rubber cement and latex body paint were explored for sampling escalator handrail, stainless steel, vinyl upholstery fabric, and finished wood flooring. Rubber cement (RC) is natural rubber latex dissolved in heptane and the latex body paint (BP) is a white body paint containing natural rubber, centrifuged latex, and water. In addition to meeting the above requirements, the RC and BP were selected because the polarities of these materials, based on the solvent, are quite different and they may have different abilities to sample potential analytes. To demonstrate the potential utility of the rubber cement and latex body paint as spread-on, peel-off collection media, the authors performed preliminary tests by contaminating surfaces with pesticides and chemicals associated with chemical warfare agents (CWAs) at an area density less than that hypothetical density estimated for sarin from the Tokyo subway attack.

Ac ce pt e

d

The analytes selected are of interest to DHS as potential and representative attribution signatures and include two pesticides and eight chemicals associated with CWAs (Figure 1) This group of chemicals include acids, bases and neutral chemicals, and the group contains a diverse set of functionalities (alcohol, amine, ester, sulfide). The pesticides are toxic to humans and could be used as poisons. The eight chemicals associated with CWAs include precursors and degradation products and are considered potential attribution signatures for CWAs. Nicotine, in addition to being present in and from the use of tobacco products, has also been used for the treatment of aphids and mites and is available in products such as Black Leaf 40 and Fulex Nicotine Fumigator. Parathion is an organophosphorus insecticide and acaricide; it reportedly was used as a CWA through intentionally contaminated clothing during the Rhodesian War in the 1970s [20]. The eight chemicals associated with CWAs are atropine, diisopropyl methylphosphonate (DIMP), dimethyl methylphosphonate (DMMP), dipinacolyl methylphosphonate (DPMP), ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA), methylphosphonic acid (MPA) and thiodiglycol (TDG). Atropine is an anticholinergic alkaloid and used in the treatment of organophosphate poisoning. Its presence at the scene of an incident could be from the efforts of the perpetrators to protect themselves or from first responders treating casualties. DIMP and DPMP are byproducts from the production of the nerve agents sarin (agent GB) and soman (agent GD), respectively, while DMMP is an early-stage intermediate in the synthesis of sarin and soman [21]. EMPA is a hydrolysis product of S(diisopropylaminoethyl) ethyl methylphosphonothiolate (agent VX). IMPA is a hydrolysis product of sarin. MPA is the ultimate hydrolysis product of sarin, soman and VX. TDG is a precursor as well as hydrolysis product of the vesicant sulfur mustard (agent HD). Three of

Page 3 of 26

these chemicals (DIMP, IMPA, MPA) were identified in the sarin recovered from the Tokyo subway attack.

us

cr

ip t

Good attribution signatures must persist and be available for subsequent sampling. Table 2 lists the boiling point (bp), vapor pressure (vp) and octanol/water partition coefficient (Kow) of the target analytes. Based on the reported boiling points and vapor pressures, the most volatile chemical is DMMP, followed by DIMP. Given the low boiling point and high vapor pressure of these chemicals, evaporation is likely a significant loss mechanism from surfaces. With the exception of the two solids, atropine and MPA, it is difficult to predict which of the other analytes are likely to experience a high degrees of loss through evaporation. This uncertainty arises from the fact that many of the vapor pressure values are based on empirical models. For example, EMPA and IMPA are very similar structurally and have similar boiling points but their reported vapor pressures differ by a factor of 10. Similarly, the two reported vapor pressure values for TDG differ by more than a factor of 10. Based on boiling points, evaporation also may be a significant loss mechanism for nicotine, DPMP, and TDG. Using vapor pressure data, evaporative loss of IMPA will be greater than that of nicotine and TDG.

M

an

The Kow provides an indication of the ability of the chemical to be absorbed into a surface substrate and into the sampling medium. Analytes with positive log Kow values are expected to be better absorbed into non-polar surfaces and sampling media. Those with negative log Kow values are expected to be better absorbed into polar surfaces and sampling media. The magnitude of the log Kow indicates the degree of partitioning.

Ac ce pt e

d

The outer surface of the escalator handrail is a mixture of natural and synthetic rubber and is non-polar. The surface of the upholstery fabric and wood flooring is a polyurethane coating which provides protection from water. Polyurethane is composed of the polar carbamate group and non-polar organic aliphatic and aromatic units and is expected to contain both polar and non-polar characteristics. The ability of the rubber cement or body paint to collect specific contaminants is expected to be predominantly determined by the relative polarities of the contaminant and the solvent (heptane or water) in which the latex is dispersed. The natural rubber latex (polyisoprene) contained within the rubber cement and body paint is non-polar. Based on the information presented in Table 2, five of the ten analytes are expected to be better sampled with the water-based body paint and five are expected to be better sampled with the heptane-based rubber cement. Preliminary tests to determine if the body paint and rubber cement are effective sampling media were performed using samples prepared by the authors. These tests were performed to demonstrate the sample collection method prior to receiving contaminated surfaces from Signature Science, LLC. The authors applied the analytes together as a solution in 10 µL of methanol such that the resulting amounts were 1.38 to 11.3 µg/cm2 (26 to 211 µg/surface sample) which is significantly less than the 31 to 98 µg/cm2 of sarin estimated to be present in the Tokyo subway cars. Five minutes after deposition of the solution containing the analytes, by which time the methanol had evaporated, the rubber cement or body paint was applied. Sixty minutes later, the dried sampling material was peeled from the surface, extracted and analyzed (see 2.2 Sampling and extraction and 2.3 Analysis). Sampling with body paint gave greater recoveries than rubber cement in all cases (Table 3). No data from any of the tests was discarded for any reason. Footnotes indicate the fraction of samples in which the analyte was found if the analyte was not detected in all samples tested. Presentation of the data in this

Page 4 of 26

manner presents this information more accurately than simply reporting the average values. Further, it is anticipated that some of the collected samples will yield negative results in the event of an actual attack or other situation resulting in contaminants being dispersed.

Ac ce pt e

d

M

an

us

cr

ip t

As shown in Table 3, each analyte was detected when body paint was used to remove the chemical signatures from the test surfaces. Overall, a greater percentage of each analyte was collected from the escalator handrail with decreasing percentages from stainless steel, vinyl upholstery, and wood flooring. An exception to this trend is parathion. Parathion was recovered most from the escalator handrail, then stainless steel, wood flooring, and upholstery fabric. That the recovery percentages follow a trend with respect to the surface type confirms that the characteristics of the surface play a role in the recovery of the analytes. Further, this suggests that, given a choice, specific surfaces should be sampled as they are more likely to yield evidence. As expected, the %RSD of the analytical results is less than 25% when the recovered percentage is 50% or greater. The %RSD often is greater than 25% when the recovered percentage is less than 50%. Rubber cement removed each of the signatures from the test surfaces; however, the amounts were significantly less than those when body paint was used. Further, the order for the recoveries from greatest to least is from wood flooring then the escalator handrail, stainless steel, and upholstery fabric with a few exceptions. MPA was not recovered from all of the test coupons using rubber cement.

2. Materials and methods 2.1 Materials and chemicals. A section of escalator handrail was obtained from Otis Elevator Co. Surface sample coupons (2.5 x 7.5 cm) of grade 304 stainless steel, vinyl upholstery fabric (face: 100% polyurethane; back: 44% polyester 37% leather 19% cotton from JoAnn Fabrics, item no. 1444470), and solid oak hardwood flooring prefinished with a polyurethane coating (Bruce Addison line from Lowes, item no. 140903, model no. CB9232) to which nicotine, parathion, atropine, DIMP, DMMP, DPMP, EMPA, IMPA, MPA and TDG had been deposited were prepared as described above or prepared by Signature Science, LLC of Austin, TX. The surfaces obtained by the authors and SSL were the same item numbers and cut to the same size. The stainless steel was of the same grade but obtained from separate suppliers. Blank surfaces used to verify no contamination other that that purposely intended were those obtained by the authors. None of the target analytes were detected from the blanks. The analytes were deposited on the outer surface of the escalator handrail and the finished side of the wood flooring, and upholstery fabric. Signature Science, LLC (SSL) prepared surfaces by spraying a highly concentrated acetonitrile solution of the analytes and then shipped them overnight to the authors at ambient temperature. Table 4 lists the theoretical amounts deposited and the actual amounts found by SSL immediately after deposition using multiple acetonitrile extractions and concentrating the combined extracts prior to analysis. The

Page 5 of 26

theoretical area densities ranged from 6.7 to 160 µg/cm2 (125 to 3000 µg/surface sample). SSL used GC-MS analysis for nicotine, parathion, DIMP, DMMP, and DPMP and LC-MS/MS analysis in the positive ion mode for atropine MPA and TDG and in the negative ion mode for EMPA and IMPA. Footnotes indicate if the analyte was not detected from all samples.

cr

ip t

The percent recoveries using multiple solvent extractions as reported by SSL are generally greater than those obtained from the use of BP or RC in the Preliminary Tests (Tables 3 and 4). The exceptions are those for DIMP from stainless steel and the wood flooring when samples using BP or RC, DMMP from stainless steel and wood flooring using BP or RC, DMMP from the upholstery fabric using BP, and DPMP from stainless steel using BP.

an

us

The surfaces received from SSL were stored at 4-7 °C upon receipt by the authors and pending subsequent sampling with rubber cement or body paint. Rubber cement (Elmer’s Products, Inc.) was purchased from a local office supply retailer. White body paint (Liquid Latex Fashions #010538) was purchased from the company’s Internet site. It is described as being ammoniafree. The authors purchased MPA, nicotine, EMPA and TDG from Sigma-Aldrich. Parathion was purchased from Fluka. DIMP, DMMP and DPMP were purchased from Alfa-Aesar, and IMPA was purchased from SynQuest. Atropine was purchased from TCI America.

Ac ce pt e

d

M

2.2 Sampling and extraction A thin layer of rubber cement or latex body paint was spread on each surface and allowed to dry at ambient temperature for 60 minutes. Eighty-five to 95 percent of the 2.5 x 7.5 cm test surface was covered by the rubber cement or latex body paint. Rubber cement and latex body paint were each spread on separate test surfaces using a nitrile-gloved hand. The rubber cement or body paint was then peeled from the surface and extracted by submersion in 5 mL of solvent (acidified methanol mixture) for 10 min with occasional swirling. The extractions were performed only once to avoid further dilution of the analytes. Concentration of the extracts was not performed to minimize the potential loss of the analytes by evaporation. The acetone/acidified methanol mixture is a 2.3:1 (v/v) mixture in which the acidified methanol is 10 mM formic acid. Extracts containing high concentrations of target analytes were further diluted as necessary with acetone for GC-MS and water for LC-MS/MS analyses. 2.3 Analysis Analyses for atropine, nicotine, parathion, DIMP, DMMP, DPMP and TDG were performed using full scan (30-450 amu) +EI GC-MS with an Agilent 6890GC interfaced to an Agilent 5973MSD. GC-separations were performed with a 1 µL splitless injection to a Restek Rtx®-35 amine column (30m x 0.25mm id, 0.5 µm film thickness) with the oven temperature at 40 °C for 2 min, increasing 20 °C/min to 220 °C and held for 15 min. The injection port was 220 °C, and the carrier gas was helium (1.2 mL/min). Quantification was achieved by use of calibration curves at concentrations of 1.0, 2.5, 5.0, 10, 25, and 50 µg/mL. EMPA, IMPA and MPA were analyzed using a Shimadzu LC-10ADVP HPLC interfaced to a Micromass Quattro II MS/MS system operated in the -ESI mode for EMPA, IMPA and MPA. The extract (50 µL) was injected onto a Thermo Hypercarb (100 x 2.1 mm, 5 µm particles) LC column held at 30 °C. The mass spectrometer source temperature was held at 150 °C, and the desolvation temperature was 350 °C. The HPLC gradient was 100% water for 0.5 min then increased to 100% methanol solution at 10 min with a flow rate of 0.20 mL/min. The following MS/MS MRM precursor:product ions (m/z) transitions

Page 6 of 26

us

cr

ip t

were monitored for EMPA 123: 95, 79; IMPA 137: 95, 79; MPA 95: 79, 77. Calibration standards for EMPA and IMPA were 0.02, 0.10, 0.20, 0.40, 1.0, 2.0, and 10 µg/mL, and for MPA they were 1.0, 2.0, 4.0, 10, 20, and 100 µg/mL. No analytical data from any of the tests was discarded for any reason (e.g., failing an outlier test). The LODs and LOQs, as concentration (µg/mL) injected into the instrument, are provided in the Supplementary Data. In the GC-MS analyses, extracts from surfaces extracted with RC contain a greater amount of background components than those from BP. Though the background did not interfere with GC-MS analysis of the analytes of interest here, it is possible that it could interfere with the analyses of other analytes. The amount of background components resulting from the BP and RC is very low for the LC-MS/MS analyses and did not interfere with the analyses. The greatest amount of background in the LCMS/MS analyses occurs for the MPA analyses. Representative chromatograms of the extracts from BP and RC that had been used to sample blank and spiked surfaces are shown in the Supplementary Data.

M

an

3. Results and discussion 3.1 Sampling results Because the utility of rubber cement and body paint was demonstrated by the authors with the preliminary tests, this sampling technique was applied to stainless steel, upholstery fabric and wood floor surfaces that had been prepared by SSL and then shipped over 1600 km and stored for 14 days (see 2.1 Materials and chemicals). This situation more closely mimics a real event in which samples are collected and sent to a laboratory for analysis after victims are rescued and the scene is secured and determined to be safe for reentry by personnel with proper protective equipment.

Ac ce pt e

d

When body paint and rubber cement were used to sample the surfaces obtained from SSL 14 days after deposition, the recoveries were substantially less than those from day 0 (Tables 4 and 5). With the exception of DIMP, DMMP and MPA, each of the analytes was found from the test surfaces when body paint was used. The inability to identify DIMP from all tests with the stainless steel surfaces and DMMP from all stainless steel and the wood flooring surfaces is consistent with the results obtained by SSL on day 0. A reduction in the recovery of DMMP from day 0 to 14 days also is consistent with data reported previously [37]. The lower recoveries of DIMP and DMMP with respect to time likely result from their relatively high volatility. Other potential factors contributing to lower detection include analyte absorption into the porous upholstery and wood surfaces and chemisorption with the stainless steel. Nicotine was better recovered than DIMP and DPMP even though the volatility of nicotine suggests it should be recovered in an amount similar to that of these two. This result implies a phenomenon other than or in addition to volatility is occurring.

On day 0, the recovered amounts of each chemical from stainless steel were equal to or greater than those from the other two surfaces (Table 4). Fourteen days after deposition (Table 5), atropine, nicotine, parathion, EMPA, IMPA, MPA and TDG remained best recovered from

Page 7 of 26

ip t

stainless steel while DIMP and DPMP were best recovered from the vinyl upholstery fabric. DMMP was best recovered from the wood flooring. The neutral phosphonate diesters (DMMP, DIMP, DPMP) and acidic phosphonic acids (EMPA, IMPA, MPA) were generally the least collected from all of the surfaces tested. Besides being less volatile than the phosphonate diesters, atropine and nicotine are alkaline, containing a basic nitrogen atom, and parathion and TDG each contain a sulfur atom. It is not known how these characteristics may influence the results.

us

cr

3.2 Resampling of surfaces To determine if the body paint or rubber cement is able to collect all of the available analyte with one sampling event, each medium was applied again to the 14-day surfaces that had just been sampled. The contact time for this second application was 20 hrs. The results from this second application are listed in Table 6. Generally, the amounts collected from this second sampling event were less than 25% of the amount collected from the first sampling event.

Ac ce pt e

d

M

an

Twelve of the 16 cases, where the amount recovered was greater than 25%, involve the upholstery fabric, three involved the wood flooring and one involved stainless steel. The most notable cases are those in which a greater amount of analyte was recovered by the second sampling event than the first. A greater amount of parathion was collected from upholstery fabric by the second sampling event using either BP or RC. DPMP was collected in a greater amount from upholstery fabric using either BP or RC and from the wood flooring using BP. The conclusion drawn from these observations is that the chemicals permeated beneath the surface and then migrated back to the surface over time. It also indicates that longer contact time between the surface and sampling medium can be advantageous. In agreement with the above conclusion, very little additional analyte was collected from the impermeable stainless steel.

4. Conclusions The application of latex body paint and rubber cement as a spread-on peel-off surface sampling media for forensic analysis of pesticides and CWA-related signatures from four common interior surface materials was demonstrated. Under the conditions of the preliminary tests using either body paint or rubber cement, each of the ten signature analytes were collected from the escalator handrail, stainless steel, vinyl upholstery fabric, and wood flooring, though MPA was not recovered in all cases using rubber cement. The body paint was superior to the rubber cement for recovering the chemicals. Based on the Kow of the 10 analytes, it was anticipated that five would be better recovered with the water-based body paint, and five would be better recovered with the heptane-based rubber cement. Because a greater percentage of each analyte was collected from the escalator handrail, than stainless steel, vinyl upholstery, and wood flooring, it is suggested that sampling from some surface types are more likely to yield chemical evidence than others in an investigation. After the samples had been transported over 1600 km and stored for two weeks, each sampling medium is able to recover most of the pesticides and CWA-related analytes. Latex body paint generally provided greater recoveries of the target analytes from stainless steel, upholstery fabric and wood flooring than rubber cement. The analytes that have low volatility are often better detected overall indicating that evaporation is a loss mechanism. Atropine, nicotine,

Page 8 of 26

cr

ip t

parathion and TDG generally persisted to a greater extent than the other analytes after 14 days even though the amounts originally deposited onto the surface by SSL were not as great as those for the more volatile analytes DMMP and DIMP. Based on boiling point and vapor pressure data, evaporation also may contribute to the loss of nicotine, DPMP, and TDG. However, nicotine and TDG were much better recovered than DPMP. Nicotine and atropine are alkaline, each containing an alkaline nitrogen atom, and TDG and parathion each contain a sulfur atom. The neutral phosphonates DIMP, DMMP and DPMP, and acidic phosphonic acids EMPA, IMPA, and MPA were generally collected the least from all of the surfaces tested. Based on the results, the presence of an amino group or sulfur atom in the molecule of interest assists in the analyte’s persistence and collection.

an

us

The ability to reapply the sampling media and detect atropine, nicotine and TDG using body paint and nicotine and parathion using rubber cement from stainless steel, upholstery fabric and wood flooring indicates that these chemicals are likely adsorbed onto the steel and absorbed into the fabric and wood surfaces. Longer contact times between the surface and sampling medium may be warranted.

Appendix A Supplementary data

M

Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.forsciint.2014.04.030. Appendix B [{(Appendix A)}] Supplementary data

Ac ce pt e

d

The following are Supplementary data to this article: mmc1

Acknowledgements Funding from Science and Technology Directorate of the U. S. Department of Homeland Security under Contract HSHQDC-11-C-00072 is gratefully acknowledged. The authors thank Otis Elevator Co. of Columbus, OH for the gift of escalator handrail samples and Signature Science, LLC of Austin, TX for providing the spiked samples of stainless steel, vinyl upholstery fabric, and wood flooring.

References [1] Department of Homeland Security chemical attribution signature studies for chemical threat agents, Solicitation number: BAA13-007 (27 Nov. 2012), https://www.fbo.gov/?s=opportunity&mode=form&id=af64b610344e2c8ef4c4a0788547d4d0& tab=core&_cview=0 [2] J.H. Kang, 1995 Tokyo subway attack: the Aum Shinrikyo case, in: M.R. Haberfeld, A. von Hassel (Eds.), A New Understanding of Terrorism: Case Studies, Trajectories and Lessons

Page 9 of 26

ip t

Learned, Springer Science + Business Media, LLC, New York, 2009, pp. 219-232. DOI: 10.1007/978-1-4419-0115-6_12. [3] Y. Ogawa, Y. Yamamura, H. Ando, M. Kadokura, T. Agata, M. Fukumoto, T. Satake, K. Machida, O. Sakai, Y. Miyata, H. Nonaka, K. Nakajima, S. Hamaya, S. Miyazaki, M. Ohida, T. Yoshioka, S. Takagi, H. Shimizu, An attack with sarin nerve gas on the Tokyo subway system and its effects on victims, in: A.T. Tu, W. Gaffield (Eds.),ACS Symposium Series 745, Natural and Selected Synthetic Toxins, American Chemical Society, 1999, pp. 333-355. DOI: 10.1021/bk2000-0745.ch022. [4] Y. Seto, The sarin gas attack in Japan and the related forensic investigation, OPCW Synthesis (2001), 14-17:

cr

http://www.opcw.org/fileadmin/OPCW/publications/synthesis/OPCW_Synthesis_2001_02Summer-June/The_Sarin_Gas_Attack_OPCW_Synthesis_June_2001.pdf.

Ac ce pt e

d

M

an

us

[5] R. Pangi, Consequence management in the 1995 sarin attacks on the Japanese subway system, BCSIA Discussion Paper 2002-4, ESDP Discussion Paper ESDP-2002-01, John F. Kennedy School of Government, Harvard University, February 2002. [6] B.C. Singer, Al T. Hodgson, H. Destaillats, T. Hotchi, K. L. Revzan, R. Sextro, Indoor sorption of surrogates for sarin and related nerve agents, Environ. Sci. Technol. 39 (2005) 3203-3214. DOI: 10.1021/es049144u. [7] The Tokyo subway lines on which the members of the Aum Shinrikyo left bags of sarin were the Marunouchi, Hibiya and Chiyoda lines. The exterior dimensions of the 02 series train cars in service since 1988 on the Marunouchi line of the Tokyo subway are 18000 mm (349 in) long, 2830 mm (111 in) wide, and 3495 mm (137.6 in) high [8]. Couplers are assumed to constitute 2 ft of the overall car length, and the floor height is assumed to be 3.76 ft (1150 mm) as in the R160 NY subway car of similar size [9]. Interior surface area and volume calculations assume that the walls, floor and ceiling of the car form a right-angled parallelepiped and the walls and 3 ceiling are 6 in. thick. Based on these dimensions, the interior volume is 94.6 m and the interior 2 walls provide 172 m of surface area. It is assumed that each passenger has 1.7 m2 of surface area [10]. The weighted average density of the sarin in the bags is calculated to be 0.995 g/mL. [8] Tokyo Metro Marunouchi Line 02 Series Information: http://www.tokyometro.jp/corporate/enterprise/passenger_rail/cars/working/marunouchi_02/ index.html [9] Alstom Transportation, Inc. and Kawasaki Rail Car, Inc. Car numbers 8313-8972 (2005-2009): http://www.nycsubway.org/perl/caption.pl?/img/cars/sheet-r160.jpg [10] T. Nagaoka, S. Watanabe, K. Sakurai, E. Kunieda, S. Watanabe, M. Taki, Y. Yamanaka, Development of realistic high-resolution whole-body voxel models of Japanese adult males and females of average height and weight, and application of models to radio-frequency electromagnetic-field dosimetry, Phys. Med. Bio. 49 (2004) 1-15. DOI: 10.1088/00319155/49/1/001. [11] Organisation for the Prohibition of Chemical Weapons, Nerve agents: https://www.opcw.org/about-chemical-weapons/types-of-chemical-agent/nerve-agents/ [12] The Sydney Morning Herald (Fairfax Media), Sorry for the one minute delay: why Tokyo’s trains rule, 25 Sep. 2013: http://www.smh.com.au/travel/travel-news/sorry-for-the-oneminute-delay-why-tokyos-trains-rule-20130925-2udv1.html [13] M.J. Small, Compounds formed from the chemical decontamination of HD, GB, and VX and their environmental fate, USAMBRDL Technical Report 8304 (June 1984), (DTIC AD-A149515). [14] P.H. Howard, G. W. Sage, J.P. Robinson, J. Jackson, Environmental fate assessments of chemical agent simulants and decontaminants, CRDC-CR-86016 (Mar. 1986), DTIC AD-B101095.

Page 10 of 26

Ac ce pt e

d

M

an

us

cr

ip t

[15] U.S. EPA, A Literature review of wipe sampling methods for chemical warfare agents and toxic industrial chemicals. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R11/079, 2007. [16] ASTM Standard D6661-01 (2006), Standard practice for field collection of organic compounds from surfaces using wipe sampling, ASTM International: West Conshohocken, PA, May 2006. Annual Book of Standards. Vol. 11.04. [17] C.E. Bernard, M.R. Berry, L.J. Wymer, L.J. Melnyk, Sampling household surfaces for pesticide residues: comparison between a press sampler and solvent-moistened wipes, Sci. Total Environment 389 (2008) 514-521. DOI: 10.1016/j.bbr.2011.03.031. [18] U.S. EPA, Sampling of common pesticides and PCBs from inert surfaces, U.S. Environmental Protection Agency National Enforcement Investigations Center, Denver, CO, EPA 330/1-90-001, 1989. [19] K.J. Beltis, P.M. Drennan, M.J. Jakubowski, B.A. Pindzola, Strippable coatings for forensic collection of trace chemicals from surfaces, Anal. Chem. 84 (2012) 10514-10517. DOI: 10.1021/ac302750k [20] P.L. Moorcraft, P. McLaughlin, The Rhodesian War: A Military History, Pen and Sword Books, Ltd., Yorkshire, England, 2008, p. 106. [21] K. Kim, O.G. Tsay, D.A. Atwood, D.G. Churchill, Destruction and detection of chemical warfare agents, Chem. Rev. 111 (2011) 5345-5403. DOI: 10.1021/cr100193y. [22] A.R. Cushny, Atropine and the hyoscyamines – a study of the action of optical isomers, J. Physiology 30 (1903) 176-194. [23] A. Pyka, M. Babuska, M. Zachariasz, A comparison of theoretical methods of calculation of partition coefficients for selected drugs, Acta Polon. Pharm. – Drug Res. 63 (2006) 159-167. [24] H.D. Young, O.A. Nelson, Vapor pressures of fumigants IV – vapor pressure of nicotine, Ind. Eng. Chem. 21 (1929) 321-322. DOI: 10.1021/ie50232a010. [25] Centers for Disease Control and Prevention, The emergency response safety and health database, nicotine: systemic agent: http://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750028.html#top [26] N-Y. Li, Y. Li, J.W. Gorrod, Determination of partition coefficients and ionisation constants of (S)(-)-nicotine and certain metabolites, Med. Sci. Res. 20 (1992) 901-902. [27] R.S. Edmundson, Dictionary of Organophosphorus Compounds, Chapman and Hall Ltd. New, York, New York, 1988. [28] W.F. Spencer, T. D. Shoup, M. M. Cliath, W. J. Farmer, R. Haque, Vapor pressures and relative volatility of ethyl and methyl parathion, J. Agric. Food Chem. 27 (1979) 273-278. DOI: 10.1021/jf60222a016) [29] B.T. Bowman, W.W. Sans, Determination of octanol-water partitioning coefficients (Kow) of 61 organophosphorus and carbamate insecticides and their relationship to respective water solubility(s) values, J. Environ. Sci. Health B18 (1983) 667-683. DOI: 10.1080/03601238309372398. [30] A.B. Butrow, J. H. Buchanan, D. E. Tevault, Vapor pressure of organophosphorus nerve agent simulant compounds, J. Chem. Eng. Data 54 (2009) 1876-1883. DOI: 10.1021/je8010024. [31] S.E. Krikorian, T.A. Chorn, J.W. King, Determination of octanol/water partition coefficients of certain organophosphorus compounds using high-performance liquid chromatography, Quant. Struct.-Act. Relat. 6 (1997) 66-69. [32] D.C. Leggett, Solvent/water partitioning of dimethyl methylphosphonate (DMMP) as a probe of solvent acidity, J. Solution Chem. 22 (1993), 289-296. DOI: 10.1007/BF00649251.

Page 11 of 26

us

cr

ip t

[33] E. Gryszkiewicz-Trochimowski, M. Bousquet, J. Quinchon, Sur la préparation et les propriétés des esters de l’acide méthanephosphonique et de l’acide méthanethionophosphonique, Bull. Soc. Chim. Fr. (1961) 1222-1225. [34] D.H. Rosenblatt, T.A. Miller, J.C. Dacre, I. Muul, D.R. Cogley, Problem definition studies on potential environmental pollutants. II. physical, chemical, toxicological, and biological properties of 16 substances, Technical Report 7509 (Dec. 1975) (DTIC AD-A030428). [35] N.B. Munro, S.S. Talmage, G.D. Griffin, L.C. Waters, A.P. Watson, J.F. King, V. Hauschild, The sources, fate, and toxicity of chemical warfare agent degradation products, Environ. Health Persp. 107 (1999) 933-973. [36] A. Brozena, D.E. Tevault, Vapor pressure of thiodiglycol, J. Chem. Eng. Data 59 (2014) 307311. DOI: 10.1021/je400978j. [37] U.S. EPA, Persistence of toxic industrial chemicals and chemical warfare agents on building materials under conventional environmental conditions: investigation report. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/075, 2008.

Atropine

M

an

Fig. 1. Chemical Structures.

DPMP

d

N CH3

N

EMPA

Ac ce pt e

Nicotine

S

O

P

O

NO2

O

O

H 3C

P

O

OH

Parathion

IMPA

O

H3C

P

O

O

DIMP O

H3C

P OCH3 OCH3

DMMP

MPA

HO HO

S

TDG

Table 1. Chemicals identified in Tokyo subway attack [3] Chemical Percentage

Density

Page 12 of 26

Ac ce pt e

d

M

an

us

cr

ip t

(wt/wt) Sarin 35% 1.089a Methylphosphonofluoridic acid (MPF) 10% 1.358b Diisopropyl methylphosphonate (DIMP) 1% 0.976c Diisopropyl fluorophosphate (DFP) 0.1% 1.055c Hexane 16% 0.655 N,N-Diethylaniline (DEA) 37% 0.956 Other, including methylphosphonic acid 0.9% 1.000d (MPA), and isopropyl methylphosphonic acid (IMPA)] a Ref [11]. b Ref [13]. c Ref [14]. d Assumed to have a density of 1. Table 2. Boiling point, vapor pressure and Kow of target analytes Chemical Bp (°C), 1 atm Vp (Pa), 25 °C log Kow Atropine (mp 115-116)a data not available 1.83b c c Nicotine 231 0.02 0.99e 247d 1.17d f g Parathion 357 0.00126 3.76h f 375 DIMP 190i 45.17i 1.03j i,k k DMMP 181 81.3 -0.61l i 111.1 DPMP 260m data not available data not available EMPA 356n 0.048n -1.15n IMPA 350o 0.45n -0.54n o p MPA (mp 101-104 °C) 0.00027 -2.28n q n TDG 280 0.0025 -0.77n 0.0653 q a b c d Ref. [22]. Ref. [23]. Ref. [24]. Ref. [25]. e Ref. [26]. f Ref. [27]. g Ref. [28]. h Ref. [29]. i Ref. [30]. j Ref. [31]. k Ref. [14]. l Ref. [32]. m Ref. [33]. n Ref. [13]. o Ref. [34]. p Ref. [35]. q Ref. [36]. Table 3. Preliminary test results, average percent recovery (average µg per surface, % RSD), n=5 Escalator Upholstery Stainless Steel Wood Flooring Handrail Fabric Analyte (µg/surface) BP RC BP RC BP RC BP RC Atropine 84% 17% 54% 6.2% 43% 3.8% 28% 17% (205) (173, (34.6, (110, (12.8, (87.2, (7.72, (57.8, (34.3, 19.9) 97.7) 13.5) 44.4) 23.7) 62.7) 68.3) 133) Nicotine 93% 13% 72% 5.0% 58% 3.1% 32% 14% (96.9) (90.0, (12.4, (60.6, (4.89, (56.0, (3.05, (31.4, (13.9, 10.7) 99.1) 18.2) 50.1) 23.5) 70.9 ) 60.0 ) 138) Parathion 95% 5.8% 85% 10% 29% 2.1% 43% 14% (76.4) (72.8, (4.46, (65.0, (8.02, (22.2, (1.61, (32.7, (10.9, 10.5) 94.4) 22.4) 34.8) 34.8) 152) 55.7) 138) DIMP 50% 2.9% 34% 3.6% 21% 0.83% 18% 7.9% (108) (53.9, (3.19, (37.1, (3.9, (22.7, (1.85, (19.9, (8.53, 13.4) 83.5) 35.1) 40.5) 10.9) 93.4) 12.8) 126) DMMP 44% 1.9% 35% 1.7%, 22% 0.90% 20% 6.4%

Page 13 of 26

(48, (2.34, (37.5, (1.77, (23.6, (0.96, (21.0, 17.5) 118) 41.0) 47.3) 14.8) 70.2) 67.3) DPMP 89% 9.0% 73% 7.1% 42% 1.9% 34% (98.9) (88.4, (8.90, (71.8, (6.98, (41.7, (1.89, (33.6, 11.0) 78.9) 26.8) 36.1) 30.0) 134) 63.2) EMPA 53% 13% 41% 4.1% 32% 2.6% 31%, (107)a (56.2, (13.4, (43.5, (4.41, (34.7, (2.73, (32.9, 15.0) 75.9) 45.5) 57.0) 33.7) 70.5) 53.7) IMPA 67% 12% 49% 3.8% 40% 2.5% 35% (25.8)a (17.2, (3.14, (12.7, (0.97, (10.2, (0.65, (9.14, 9.35) 95.6) 47.8) 52.1) 38.5) 57.0) 49.5) MPA 47% 10% 27.1 2.6% 22% 0.76% 22% (211)a (99.6, (22.0, (57.2, (5.58, (45.5, (1.60, (46.4, 10.8) 113)b 47.3) 131)c 42.1) 239)d 53.0) TDG 80%, 9.1% 63% 4.2% 49% 1.7% 29% (109) (87.7, (9.86, (62.5, (4.13, (48.5, (1.66, (28.4, 11.7) 109) 16.9) 48.2) 23.4) 101) 68.9) a b c d e n = 10. detected in 9/10. detected in 4/10. detected in 2/10. detected in 5/10. Table 4. Theoretical mass deposited per surface and day zero detectionsa Average percent recovery reported for 2 lots of surfaces, (average µg, % RSD), n=8 Analyte (theoretical Upholstery µg/surface) Stainless Steel Fabric Wood Flooring Atropine (150) 93% (139, 13.3) 61% (91.2, 20.2) 54% (80.8, 32.0) Nicotine (375) 94% (354, 11.0) 71% (267, 22.6) 56% (210, 35.2) Parathion (375) 100% (374, 5.5) 69% (259,25.6 ) 58% (218, 33.7) DIMP (3000) 1.5%b (45.2, 168) 28% (841, 36.3) 2.2% (65.4, 111) DMMP (1500) 0%c (0, --) 15% (227, 54.6 ) 0.9%b (13.9, 111) DPMP (500) 56% (281, 24.4) 56% (281, 22.6) 35% (177, 41.1) EMPA (150) 75% (112, 10.9 ) 49% (74.0, 18.4) 43% (64.6, 33.2) IMPA (125) 113% (142, 14.2) 71% (89.2, 41.1) 68% (84.7, 38.4) MPA (200) 127% (254, 8.8) 82% (163,25.4) 67% (135, 38.6) TDG (250) 93% (233, 10.8) 69% (172, 21.4) 56% (141, 35.2) a b c Information provided by SSL. detected in 4/8. detected in 0/8. Table 5. Amount collected 14 days after deposition Average amount in µg (% RSD), n=10 Stainless Steel Upholstery Fabric Wood Flooring Analyte BP RC BP RC BP RC Atropine 85.0 1.90 37.0 1.46 46.6 1.78 (29.5) (77.0) (85.9) (47.3) (44.6) (91.7)a Nicotine 244 21.0 86.4 7.98 127 13.6 (15.6) (30.4) (47.2) (25.8) (31.5) (51.0) Parathion 243 71.1 12.8 0.570 106 32.1 (17.9) (28.8) (55.0) (36.1) (26.0) (55.1) DIMP 0.035 0.010 0.940 0.455 0.410 0.025 (69.0)b (211)c (42.5) (23.4) (109) (105)d DMMP 0.00 0.00 0.095 0.065 0.120 0.00

(6.86, 104) 11% (10.9, 132) 11% (11.8, 133) 11% (2.82, 128) 7.2% (15.3, 178)e 11% (11.1, 147)

Ac ce pt e

d

M

an

us

cr

ip t

(107)

Page 14 of 26

Ac ce pt e

d

M

an

us

cr

ip t

(--)e (--)e (46.1) (37.2) (102) (--)e DPMP 0.460 0.055 3.60 0.420 2.31 0.205 (41.6) (51.6)f (51.6) (27.0) (49.9) (64.5) EMPA 13.6 2.34 5.47 0.941 7.86 1.22 (37.3) (34.7) (86.4) (43.4) (45.6) (59.9) IMPA 28.7 6.81 10.1 2.00 16.4 3.28 (37.6) (30.4) (87.1) (36.5) (48.2) (49.6) MPA 17.1 2.87 9.06 2.32 11.9 0.351 (36.9) (36.6)f (66.0) (88.1)g (43.2) (--)h TDG 148 11.7 19.2 1.26 50.1 6.26 (9.06) (40.7) (86.3) (45.8) (48.1) (62.2) a detected in 8/10. b detected in 7/10. c detected in 2/10. d detected in 5/10. e detected in 0/10. f detected in 9/10. g detected in 6/10. h detected in 1/10. Table 6. Amount collected by 2nd application of peelable medium Average amount in µg (% RSD), n=10 Stainless Steel Upholstery Fabric Wood Flooring Analyte BP RC BP RC BP RC Atropine 1.24 0.00 6.35 0.00 1.64 0.00 (65.8) (--)a (23.8) (--)a (50.8) (--)a Nicotine 0.305 2.18 9.26 2.58 1.50 1.16 (31.3) (24.0) (20.1) (24.0) (51.2) (60.8) Parathion 0.00 2.64 61.8 1.89 33.3 4.68 (--)a (74.7) (17.3) (84.5) (29.1) (66.6) DIMP 0.00 0.00 1.24 0.195 0.100 0.00 a a (--) (--) (19.1) (25.5) (40.8) (--)a DMMP 0.00 0.00 0.070 0.040 0.025 0.00 (--)a (--)a (36.9) (52.7)b (105)c (--)a DPMP 0.00 0.00 19.7 1.34 3.00 0.120 (--)a (--)a (15.4) (33.4) (43.2) (62.7) EMPA 6.23 0.116 3.01 0.114 0.785 0.072 (63.9) (26.1) (35.4) (29.7) (42.2) (64.6) IMPA 1.22 0.215 6.06 0.173 1.49 0.117 (59.4) (27.2) (35.0) (33.5) (40.1) (68.9) MPA 0.00 0.00 0.00 0.00 0.00 0.00 (--)a (--)a (--)a (--)a (--)a (--)a TDG 0.560 0.375 7.12 0.175 3.68 0.175 (43.9) (52.7) (33.3) (55.9) (30.8) (102)d a detected in 0/10. b detected in 8/10. c detected in 5/10. d detected in 7/10.

Supplementary data Table S1. Limits of detection and limits of quantitation as concentration (µg/mL) injected into the instrument Analyte LOD LOQ Atropine 0.336 1.01

Page 15 of 26

0.600 1.06 0.294 2.39 0.543 0.0037 0.0028 0.066 0.810

ip t

0.200 0.355 0.0979 0.797 0.181 0.0012 0.00093 0.022 0.270

cr

Nicotine Parathion DIMP DMMP DPMP EMPA IMPA MPA TDG

us

1.2e+07 1.1e+07

an

1e+07 9000000 8000000

M

7000000 6000000

d

5000000

Ac ce pt e

4000000 3000000 2000000 1000000

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

22.00

24.00

26.00

28.00

Figure S1. Chromatogram from full-scan GC-MS analysis of the extract from body paint used to sample an escalator handrail blank. The large peak at approximately 10 min is the internal standard.

Page 16 of 26

3e+07

ip t

2.5e+07

cr

2e+07

us

1.5e+07

1e+07

6.00

8.00

10.00

12.00

14.00

16.00

18.00

an

5000000

20.00

22.00

24.00

26.00

28.00

M

Figure S2. Chromatogram from full-scan GC-MS analysis of the extract from body paint used to sample an escalator handrail spike. Abundance

d

TIC: 0228034.D

3400000

Ac ce pt e

3200000 3000000 2800000 2600000 2400000 2200000 2000000 1800000 1600000 1400000 1200000 1000000 800000 600000 400000 200000

6.00

8.00

10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00

Time-->

Figure S3. Chromatogram from full-scan GC-MS analysis of the extract from rubber cement used to sample an escalator handrail blank.

Page 17 of 26

5500000 5000000

ip t

4500000 4000000 3500000

cr

3000000 2500000

us

2000000 1500000

500000 8.00

10.00

12.00

14.00

16.00

18.00

20.00

22.00

24.00

26.00

28.00

M

6.00

an

1000000

Ac ce pt e

d

Figure S4. Chromatogram from full-scan GC-MS analysis of the extract from rubber cement used to sample an escalator handrail spike.

Page 18 of 26

ip t cr us an M

Ac ce pt e

d

Figure S5. Chromatogram from MRM for EMPA analysis of the extract from body paint used to sample an escalator handrail blank.

Figure S6. Chromatogram from MRM for EMPA analysis of the extract from body paint used to sample an escalator handrail spike.

Page 19 of 26

ip t cr us an M

Ac ce pt e

d

Figure S7. Chromatogram from MRM for IMPA analysis of the extract from body paint used to sample an escalator handrail blank.

Figure S8. Chromatogram from MRM for IMPA analysis of the extract from body paint used to sample an escalator handrail spike.

Page 20 of 26

ip t cr us an M d Ac ce pt e

Figure S9. Chromatogram from MRM for MPA analysis of the extract from body paint used to sample an escalator handrail blank.

Page 21 of 26

ip t cr us an M d Ac ce pt e

Figure S10. Chromatogram from MRM for MPA (7.57 min.) analysis of the extract from body paint used to sample an escalator handrail spike.

Page 22 of 26

ip t cr us an

Ac ce pt e

d

M

Figure S11. Chromatogram from MRM for EMPA analysis of the extract from rubber cement used to sample an escalator handrail blank.

Figure S12. Chromatogram from MRM for EMPA analysis of the extract from rubber cement used to sample an escalator handrail spike.

Page 23 of 26

ip t cr us an M

Ac ce pt e

d

Figure S13. Chromatogram from MRM for IMPA analysis of the extract from rubber cement used to sample an escalator handrail blank.

Figure S14. Chromatogram from MRM for IMPA analysis of the extract from rubber cement used to sample an escalator handrail spike.

Page 24 of 26

ip t cr us an M d Ac ce pt e

Figure S13. Chromatogram from MRM for MPA analysis of the extract from rubber cement used to sample an escalator handrail blank.

Page 25 of 26

ip t cr us an M d Ac ce pt e

Figure S14. Chromatogram from MRM for MPA (7.57 min.) analysis of the extract from rubber cement used to sample an escalator handrail spike.

Page 26 of 26