Targeting miR-497-5p rescues human keratinocyte dysfunction upon skin exposure to sulfur mustard.

Sulfur mustard (SM) is a highly toxic chemical warfare agent. Exposure to SM results in various pathologies including skin lesions with subsequent impaired wound healing. To date, there are no effective treatments available. Here we discover a SM-triggered pathomechanism involving miR-497-5p and its target survivin which contributes to keratinocyte dysfunction. Transcriptome analysis using RNA-seq in normal human epidermal keratinocytes (NHEK) revealed that SM evoked differential expression of 1896 mRNAs and 25 miRNAs with many of these RNAs known to be involved in keratinocyte function and wound healing. We demonstrated that keratinocyte differentiation and proliferation were efficiently regulated by miRNAs induced in skin cells after exposure to SM. The inhibition of miR-497-5p counteracted SM-induced premature differentiation and stimulated proliferation of NHEK. In addition, we showed that microneedle-mediated transdermal application of lipid-nanoparticles containing miR-497-5p inhibitor restored survivin biosynthesis and cellular functionality upon exposure to SM using human skin biopsies. Our findings expand the current understanding of SM-associated molecular toxicology in keratinocytes and highlight miR-497-5p as feasible clinical target for specific skin therapy in SM-exposed patients and beyond.

Repurposing FDA-approved drugs to treat chemical weapon toxicities: Interactive case studies for trainees.

The risk of a terrorist attack in the United States has created challenges on how to effectively treat toxicities that result from exposure to chemical weapons. To address this concern, the United States has organized a trans-agency initiative across academia, government, and industry to identify drugs to treat tissue injury resulting from exposure to chemical threat agents. We sought to develop and evaluate an interactive educational session that provides hands-on instruction on how to repurpose FDA-approved drugs as therapeutics to treat toxicity from exposure to chemical weapons. As part of the Rutgers Summer Undergraduate Research Fellowship program, 23 undergraduate students participated in a 2-h session that included: (1) an overview of chemical weapon toxicities, (2) a primer on pharmacology principles, and (3) an interactive session where groups of students were provided lists of FDA-approved drugs to evaluate potential mechanisms of action and suitability as countermeasures for four chemical weapon case scenarios. The interactive session culminated in a competition for the best grant "sales pitch." From this interactive training, students improved their understanding of (1) the ability of chemical weapons to cause long-term toxicities, (2) impact of route of administration and exposure scenario on drug efficacy, and (3) re-purposing FDA-approved drugs to treat disease from chemical weapon exposure. These findings demonstrated that an interactive training exercise can provide students with new insights into drug development for chemical threat agent toxicities.

A Glycoprotein-Based Surface-Enhanced Raman Spectroscopy-Lateral Flow Assay Method for Abrin and Ricin Detection.

Abrin and ricin, both type II ribosome-inactivating proteins, are toxins of significant concern and are under international restriction by the Chemical Weapons Convention and the Biological and Toxin Weapons Convention. The development of a rapid and sensitive detection method for these toxins is of the utmost importance for the first emergency response. Emerging rapid detection techniques, such as surface-enhanced Raman spectroscopy (SERS) and lateral flow assay (LFA), have garnered attention due to their high sensitivity, good selectivity, ease of operation, low cost, and disposability. In this work, we generated stable and high-affinity nanotags, via an efficient freezing method, to serve as the capture module for SERS-LFA. We then constructed a sandwich-style lateral flow test strip using a pair of glycoproteins, asialofetuin and concanavalin A, as the core affinity recognition molecules, capable of trace measurement for both abrin and ricin. The limit of detection for abrin and ricin was 0.1 and 0.3 ng/mL, respectively. This method was applied to analyze eight spiked white powder samples, one juice sample, and three actual botanic samples, aligning well with cytotoxicity assay outcomes. It demonstrated good inter-batch and intra-batch reproducibility among the test strips, and the detection could be completed within 15 min, indicating the suitability of this SERS-LFA method for the on-site rapid detection of abrin and ricin toxins.

How does organophosphorus chemical warfare agent exposure affect respiratory physiology in mice?

In the absence of appropriate medical care, exposure to organophosphorus nerve agents, such as VX, can lead to respiratory failure, and potentially death by asphyxiation. Despite the critical role of respiratory disturbances in organophosphorus-induced toxicity, the nature and underlying mechanisms of respiratory failure remain poorly understood. This study aimed to characterize respiratory alterations by determining their type and duration in mice exposed to a subcutaneous sublethal dose of VX. Respiratory ventilation in Swiss mice was monitored using dual-chamber plethysmography for up to 7 days post-exposure. Cholinesterase activity was assessed via spectrophotometry, and levels of inflammatory biomarkers were quantified using Luminex technology in blood and tissues involved in respiration (diaphragm, lung, and medulla oblongata). Additionally, a histological study was conducted on these tissues to ensure their structural integrity. Ventilatory alterations appeared 20-25 minutes after the injection of 0.9 LD50 VX and increased until the end of the recording, i.e., 40 minutes after intoxication. Concurrent with the occurrence of apnea, increased inspiratory and expiratory times resulted in a significant decrease in respiratory rate in exposed mice compared to controls. Ventilatory amplitude and, consequently, minute volume were reduced, while specific airway resistance significantly increased, indicating bronchoconstriction. These ventilatory effects persisted up to 24 or even 72 hours post-intoxication, resolving on the 7th day. They were correlated with a decrease in acetylcholinesterase activity in the diaphragm, which persisted for up to 72 hours, and with the triggering of an inflammatory reaction in the same tissue. No significant histologic lesions were observed in the examined tissues. The ventilatory alterations observed up to 72 hours post-VX exposure appear to result from a functional failure of the respiratory system rather than tissue damage. This comprehensive characterization contributes to a better understanding of the respiratory effects induced by VX exposure, which is crucial for developing specific medical countermeasures.

Ultrathin WO3 Nanosheets/Pd with Strong Metal-Support Interactions for Highly Sensitive and Selective Detection of Mustard-Gas Simulants.

Exposure to mustard gas can cause damage or death to human beings, depending on the concentration and duration. Thus, developing high-performance mustard-gas sensors is highly needed for early warning. Herein, ultrathin WO3 nanosheet-supported Pd nanoparticles hybrids (WO3 NSs/Pd) are prepared as chemiresistive sulfur mustard simulant (e.g., 2-chloroethyl ethyl sulfide, 2-CEES) gas sensors. As a result, the optimal WO3 NSs/Pd-2 (2 wt % of Pd)-based sensor exhibits a high response of 8.5 and a rapid response/recovery time of 9/92 s toward 700 ppb 2-CEES at 260 °C. The detection limit could be as low as 15 ppb with a response of 1.4. Moreover, WO3 NSs/Pd-2 shows good repeatability, 30-day operating stability, and good selectivity. In WO3 NSs/Pd-2, ultrathin WO3 NSs are rich in oxygen vacancies, offer more sites to adsorb oxygen species, and make their size close to or even within the thickness of the so-called electron depletion layer, thus inducing a large resistance change (response). Moreover, strong metal-support interactions (SMSIs) between WO3 NSs and Pd nanoparticles enhance the catalytic redox reaction performance, thereby achieving a superior sensing performance toward 2-CEES. These findings in this work provide a new approach to optimize the sensing performance of a chemiresistive sensor by constructing SMSIs in ultrathin metal oxides.

Oxidative Stress: An Intersection Between Radiation and Sulfur Mustard Lung Injury.

Nuclear and chemical weapons of mass destruction share both a tragic and beneficial legacy in mankind's history and health. The horrific health effects of ionizing radiation and mustard gas exposures unleashed during disasters, wars, and conflicts have been harnessed to treat human health maladies. Both agents of destruction have been transformed into therapies to treat a wide range of cancers. The discovery of therapeutic uses of radiation and sulfur mustard was largely due to observations by clinicians treating victims of radiation and sulfur mustard gas exposures. Clinicians identified vulnerability of leukocytes to these agents and repurposed their use in the treatment of leukemias and lymphomas. Given the overlap in therapeutic modalities, it goes to reason that there may be common mechanisms to target as protective strategies against their damaging effects. This commentary will highlight oxidative stress as a common mechanism shared by both radiation and sulfur mustard gas exposures and discuss potential therapies targeting oxidative stress as medical countermeasures against the devastating lung diseases wrought by these agents.

Brominated oxime nucleophiles are efficiently reactivating cholinesterases inhibited by nerve agents.

Six novel brominated bis-pyridinium oximes were designed and synthesized to increase their nucleophilicity and reactivation ability of phosphorylated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Their pKa was valuably found lower to parent non-halogenated oximes. Stability tests showed that novel brominated oximes were stable in water, but the stability of di-brominated oximes was decreased in buffer solution and their degradation products were prepared and characterized. The reactivation screening of brominated oximes was tested on AChE and BChE inhibited by organophosphorus surrogates. Two mono-brominated oximes reactivated AChE comparably to non-halogenated analogues, which was further confirmed by reactivation kinetics. The acute toxicity of two selected brominated oximes was similar to commercially available oxime reactivators and the most promising brominated oxime was tested in vivo on sarin- and VX-poisoned rats. This brominated oxime showed interesting CNS distribution and significant reactivation effectiveness in blood. The same oxime resulted with the best protective index for VX-poisoned rats.

Immediate dry decontamination using efficient absorbent materials is beneficial following skin exposure to low-volatile toxic chemicals.

In a chemical mass casualty incident requiring skin decontamination, dry removal using absorbent materials may be beneficial to enable immediate decontamination. The efficacy of absorbent materials has therefore been evaluated, alone or procedures including both dry and wet decontamination, following skin exposure to two low volatile toxic chemicals using an in vitro human skin penetration model. Additionally, removal using active carbon wipes was evaluated with or without the Dahlgren Decon solution. All dry decontamination procedures resulted in a significantly decreased skin penetration rate of the industrial chemical 2-butoxyethanol compared to the control without decontamination. Wet decontamination following dry absorption significantly improved the efficacy compared to dry removal alone. Dry decontamination post-exposure to the chemical warfare nerve agent VX showed no decontamination efficacy. However, dry and wet decontamination resulted in a decreased agent skin penetration rate during the last hour of the experiment. At -15°C, significantly reduced VX skin penetration rates were demonstrated for both dry decontamination alone and the dry and wet decontamination procedure. The Dahlgren Decon solution significantly reduced the amount of VX penetrating the skin, but the active carbon wipe alone did not impact the skin penetration rate. In conclusion, absorbent materials are beneficial for the removal of low-volatile chemicals from the skin, but the degree of efficacy varies between chemicals. Despite the variability, immediate dry decontamination using available absorbent materials prior to wet decontamination is recommended as a general procedure for skin decontamination. The procedure should also be prioritized in cold-weather conditions to prevent patient hypothermia.

Visual detection and discrimination of nerve and blood agents using a dual-site fluorescent probe in living cells and mice.

Of all chemical warfare agents (CWAs), only nerve and blood agents cause massive mortality at low concentrations. To better detect and discriminate nerve and blood agents, a reliable detection method is desirable. We report a series of fluorescent probes for nerve and blood agent detection. Among the tested probes, SR-Pip detected nerve and blood agents quickly (within 10 s for nerve agents and 1 min for blood agents). SR-Pip coupled with nerve agent produced a weak orange fluorescence with good sensitivity [limit of detection (LOD)= 5.5 µM]. Upon reaction with blood agent, the fluorescence of SR-Pip changed from orange fluorescence to blue fluorescence with detection limits as low as 9.6 nM. This probe effectively visualised different concentrations of nerve agents in living cells and mice. A portable test kit using SR-Pip instantly detected nerve and blood agents. To the best of our knowledge, SR-Pip is the first fluorescent probe for nerve and blood agent detection.

Baseline physiological data from anesthetized pigs in a VX intoxication model.

Over the past fifty years, swine models have been used for organophosphorus intoxication studies. Among these studies and others on the swine model in general, some physiological data, especially cholinesterase activity highly impacted by organophosphorus compounds like nerve agent VX, still need to be completed. To support and compare our model to others, we have published the experimental protocol, the physiological values of 31 juvenile anesthetized pigs, and the 6 h-follow-up of six supplementary anesthetized control animals and 7 VX-intoxicated pigs. We reported hemodynamics and respiratory parameters, blood levels in several biochemical parameters, blood gas, and complete blood count and compared them to the literature. We also focused on tissue and blood cholinesterase activities and detailed them for acetylcholinesterase and butyrylcholinesterase. After establishing a broad physiological data set consistent with the literature, we reported several cardio-respiratory parameters that seem more affected by an organophosphate intoxication, like heart rate, arterial blood pressure, cardiac output, and respiratory rate. Within the blood, oxygen saturation (SpO2), lactatemia, base excess, and glycemia can also be measured and associated with the other parameters to evaluate the life-threatening status. This swine model is currently used to develop and evaluate medical countermeasures against organophosphate nerve agent intoxications.

Revealing nitrogenous VX metabolites and the whole-molecule VX metabolism in the urine of guinea pigs.

VX, a well-known organophosphorus nerve agent (OPNA), poses a significant threat to public safety if employed by terrorists. Obtaining complete metabolites is critical to unequivocally confirm its alleged use/exposure and elucidate its whole-molecular metabolism. However, the nitrogenous VX metabolites containing 2-diisopropylaminoethyl moiety from urinary excretion remain unknown. Therefore, this study applied a newly developed untargeted workflow platform to discover and identify them using VX-exposed guinea pigs as animal models. 2-(N,N-diisopropylamino)ethanesulfonic acid (DiPSA) was revealed as a novel nitrogenous VX metabolite in urine, and 2-(Diisopropylaminoethyl) methyl sulfide (DAEMS) was confirmed as another in plasma, indicating that VX metabolism differed between urine and plasma. It is the first report of a nitrogenous VX metabolite in urine and a complete elucidation of the VX metabolic pathway. DiPSA was evaluated as an excellent VX exposure biomarker. The whole-molecule VX metabolism in urine was characterized entirely for the first time via the simultaneous quantification of DiPSA and two known P-based biomarkers. About 52.1% and 32.4% of VX were excreted in urine as P-based and nitrogenous biomarkers within 24 h. These findings provide valuable insights into the unambiguous detection of OPNA exposure/intoxication and human and environmental exposure risk assessment.

Pulmonary rehabilitation in Iranian outpatients with mustard gas lung disease: a randomised controlled trial.

OBJECTIVE: People with mustard gas lung disease experience cough, sputum, breathlessness and exercise limitation. We hypothesised that pulmonary rehabilitation (PR) would be beneficial in this condition. DESIGN: An assessor-blind, two-armed, parallel-design randomised controlled clinical trial. SETTING: Secondary care clinics in Iran. PARTICIPANTS: 60 men with breathlessness due to respiratory disease caused by documented mustard gas exposure, mean (SD) age 52.7 (4.36) years, MRC dyspnoea score 3.5 (0.7), St. George's Respiratory Questionnaire (SGRQ) 72.3 (15.2). INTERVENTIONS: Participants were allocated either to a 6-week course of thrice-weekly PR (n=31) or to usual care (n=29), with 6-week data for 28 and 26, respectively. OUTCOME MEASURES: Primary endpoint was change in cycle endurance time at 70% baseline exercise capacity at 6 weeks. Secondary endpoints included 6 min walk distance, quadriceps strength and bulk, body composition and health status. For logistical reasons, blood tests that had been originally planned were not performed and 12-month follow-up was available for only a small proportion. RESULTS: At 6 weeks, cycle endurance time increased from 377 (140) s to 787 (343) s with PR vs 495 (171) s to 479 (159) s for usual care, effect size +383 (231) s (p<0.001). PR also improved 6 min walk distance+103.2 m (63.6-142.9) (p<0.001), MRC dyspnoea score -0.36 (-0.65 to -0.07) (p=0.016) and quality of life; SGRQ -8.43 (-13.38 to -3.48) p<0.001, as well as quadriceps strength+9.28 Nm (1.89 to 16.66) p=0.015. CONCLUSION: These data suggest that PR can improve exercise capacity and quality of life in people with breathlessness due to mustard gas lung disease and support the wider provision of this form of care. TRIAL REGISTRATION NUMBER: IRCT2016051127848N1.

Effective skin decontamination with RSDL® (reactive skin decontamination lotion kit) following dermal exposure to a Novichok class nerve agent.

In recent years, various poisoning incidents have been reported, involving the alleged use of the so-called Novichok agents, resulting in their addition to the Schedule I list of the Organisation for the Prohibition of Chemical Warfare (OPCW). As the physicochemical properties of these agents are different from the 'classical' nerve agents, such as VX, research is needed to evaluate whether and to what extent existing countermeasures are effective. Here, we evaluated the therapeutic potential of RSDL® (Reactive Skin Decontamination Lotion Kit) for the neutralization of percutaneous toxicity caused by Novichok agents, both in vitro and in vivo. Experiments showed the three selected Novichok agents (A230, A232, A234) could be degraded by RSDL lotion, but at a different rate. The half-life of A234, in the presence of an excess of RSDL lotion, was 36 min, as compared to A230 (<5 min) and A232 (18 min). Following dermal exposure of guinea pigs to A234, application of the RSDL kit was highly effective in preventing intoxication, even when applied up until 30 min following exposure. Delayed use of the RSDL kit until the appearance of clinical signs of intoxication (3-4 h) was not able to prevent intoxication progression and deaths. This study determines RSDL decontamination as an effective treatment strategy for dermal exposure to the Novichok agent A234 and underscores the importance of early, forward use of skin decontamination, as rapidly as possible.

Identification of early events in nitrogen mustard pulmonary toxicity that are independent of infiltrating inflammatory cells using precision cut lung slices.

Nitrogen mustard (NM; mechlorethamine) is a cytotoxic vesicant known to cause acute lung injury which can progress to chronic disease. Due to the complex nature of NM injury, it has been difficult to analyze early responses of resident lung cells that initiate inflammation and disease progression. To investigate this, we developed a model of acute NM toxicity using murine precision cut lung slices (PCLS), which contain all resident lung cell populations. PCLS were exposed to NM (1-100 µM) for 0.5-3 h and analyzed 1 and 3 d later. NM caused a dose-dependent increase in cytotoxicity and a reduction in metabolic activity, as measured by LDH release and WST-1 activity, respectively. Optimal responses were observed with 50 µM NM after 1 h incubation and these conditions were used in further experiments. Analysis of PCLS bioenergetics using an Agilent Seahorse showed that NM impaired both glycolytic activity and mitochondrial respiration. This was associated with injury to the bronchial epithelium and a reduction in methacholine-induced airway contraction. NM was also found to cause DNA damage in bronchial epithelial cells in PCLS, as measured by expression of γ-H2AX, and to induce oxidative stress, which was evident by a reduction in glutathione levels and upregulation of the antioxidant enzyme catalase. Cleaved caspase-3 was also upregulated in airway smooth muscle cells indicating apoptotic cell death. Characterizing early events in NM toxicity is key in identifying therapeutic targets for the development of efficacious countermeasures.

The risk associated with organophosphorus nerve agents: from their discovery to their unavoidable threat, current medical countermeasures and perspectives.

The first organophosphorus nerve agent was discovered accidently during the development of pesticides, shortly after the first use of chemical weapons (chlorine, phosgene) on the battlefield during World War I. Despite the Chemical Weapons Convention banning these substances, they have still been employed in wars, terrorist attacks or political assassinations. Characterised by their high lethality, they target the nervous system by inhibiting the acetylcholinesterase (AChE) enzyme, preventing neurotransmission, which, if not treated rapidly, inevitably leads to serious injury or the death of the person intoxicated. The limited efficacy of current antidotes, known as AChE reactivators, pushes research towards new treatments. Numerous paths have been explored, from modifying the original pyridinium oximes to developing hybrid reactivators seeking a better affinity for the inhibited AChE. Another crucial approach resides in molecules more prone to cross the blood-brain barrier: uncharged compounds, bio-conjugated reactivators or innovative formulations. Our aim is to raise awareness on the threat and toxicity of organophosphorus nerve agents and to present the main synthetic efforts deployed since the first AChE reactivator, to tackle the task of efficiently treating victims of these chemical warfare agents.

Chromogenic Detection of the Organophosphorus Nerve Agent Simulant DCP Mediated by Rhodium(II,II) Paddlewheel Complexes.

Organophosphorus nerve agents (OPNAs) pose a great threat to humanity. Possessing extreme toxicity, rapid lethality, and an unassuming appearance, these chemical warfare agents must be quickly and selectively identified so that treatment can be administered to those affected. Chromogenic detection is the most convenient form of OPNA detection, but current methods suffer from false positives. Here, nitrogenous base adducts of dirhodium(II,II) acetate were synthesized and used as chromogenic detectors of diethyl chlorophosphate (DCP), an OPNA simulant. UV-vis spectrophotometry was used to evaluate the sensitivity and selectivity of the complexes in the detection of DCP. Visual limits of detection (LOD) for DCP were as low as 1.5 mM DCP, while UV-vis-based LODs were as low as 0.113 µM. The dirhodium(II,II) complexes were also tested with several potential interferents, none of which produced a visual color change that could be mistaken for OPNA response. Ultimately, the Rh2(OAc)4(1,8-diazabicyclo[5.4.0]undec-7-ene)2 complex showed the best combination of detection capability and interferent resistance. These results, when taken together, show that dirhodium(II,II) paddlewheel complexes with nitrogenous base adducts can produce instant, selective, and sensitive detection of DCP. It is our aim to further explore and apply this new motif to produce even more capable OPNA sensors.

Dexamethasone sodium phosphate loaded nanoparticles for prevention of nitrogen mustard induced corneal injury.

Nitrogen mustard (NM) is a potent vesicating chemical warfare agent that is primarily absorbed through skin, inhalation, or ocular surface. Ocular exposure of NM can cause acute to chronic keratopathy which can eventually lead to blindness. There is a current lack of effective countermeasures against ocular exposure of NM despite their imperative need. Herein, we aim to explore the sustained effect of Dexamethasone sodium phosphate (DSP)-loaded polymeric nanoparticles (PLGA-DSP-NP) following a single subconjunctival injection in the management and prevention of corneal injury progression upon exposure to NM. DSP is an FDA approved corticosteroid with proven anti-inflammatory properties. We formulated PLGA-DSP-NP with zinc chelation ion bridging method using PLGA polymer, with particles of approximately 250 nm and a drug loading of 6.5 wt%. Under in vitro sink conditions, PLGA-DSP-NP exhibited a sustained drug release for two weeks. Notably, in NM injured cornea, a single subconjunctival (SCT) injection of PLGA-DSP-NP outperformed DSP eyedrops (0.1%), DSP solution, placebo NP, and saline, significantly mitigating corneal neovascularization, ulceration, and opacity for the two weeks study period. Through PLGA-DSP-NP injection, sustained DSP release hindered inflammatory cytokine recruitment, angiogenic factors, and endothelial cell proliferation in the cornea. This strategy presents a promising localized corticosteroid delivery system to effectively combat NM-induced corneal injury, offering insights into managing vesicant exposure.

Chloropicrin induced ocular injury: Biomarkers, potential mechanisms, and treatments.

Ocular tissue, especially the cornea, is overly sensitive to chemical exposures. The availability and adoption of chemical threat agent chloropicrin (CP) is growing in the United States as a pesticide and fumigant; thereby increasing the risk of its use in warfare, terrorist attacks and non-intentional exposure. Exposure to CP results in immediate ocular, respiratory, and dermal injury; however, we lack knowledge on its mechanism of toxicity as well as of its breakdown products like chlorine and phosgene, and effective therapies are elusive. Herein, we have reviewed the recent findings on exposure route, toxicity and likely mechanisms of CP induced ocular toxicity based on other vesicating chemical warfare agents that cause ocular injury. We have focused on the implication of their toxicity and mechanistic outcomes in the ocular tissue, especially the cornea, which could be useful in the development of broad-spectrum effective therapeutic options. We have discussed on the potential countermeasures, overall hallmarks and challenges involved in studying ocular injuries from chemical threat agent exposures. Finally, we reviewed useful available technologies and methods that can assist in the identification of effective medical countermeasures for chemical threat agents related ocular injuries.

Use of carbonyldiimidazole as a derivatization agent for the detection of pinacolyl alcohol, a forensic marker for Soman, by EI-GC-MS and LC-HRMS in official OPCW proficiency test matrices.

Pinacolyl alcohol (PA), a key forensic marker for the nerve agent Soman (GD), is a particularly difficult analyte to detect by various analytical methods. In this work, we have explored the reaction between PA and 1,1'-carbonyldiimidazole (CDI) to yield pinacolyl 1H-imidazole-1-carboxylate (PIC), a product that can be conveniently detected by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Regarding its GC-MS profile, this new carbamate derivative of PA possesses favorable chromatographic features such as a sharp peak and a longer retention time (RT = 16.62 min) relative to PA (broad peak and short retention time, RT = 4.1 min). The derivative can also be detected by LC-HRMS, providing an avenue for the analysis of this chemical using this technique where PA is virtually undetectable unless present in large concentrations. From a forensic science standpoint, detection of this low molecular weight alcohol signals the past or latent presence of the nerve agent Soman (GD) in a given matrix (i.e., environmental or biological). The efficiency of the protocol was tested separately in the analysis and detection of PA by EI-GC-MS and LC-HRMS when present at a 10 µg/mL in a soil matrix featured in the 44th PT and in a glycerol-rich liquid matrix featured in the 48th Official Organization for the Prohibition of Chemical Weapons (OPCW) Proficiency Test when present at a 5 µg/mL concentration. In both scenarios, PA was successfully transformed into PIC, establishing the protocol as an additional tool for the analysis of this unnatural and unique nerve agent marker by GC-MS and LC-HRMS.

Biomarker profiling in plants to distinguish between exposure to chlorine gas and bleach using LC-HRMS/MS and chemometrics.

Since its first employment in World War I, chlorine gas has often been used as chemical warfare agent. Unfortunately, after suspected release, it is difficult to prove the use of chlorine as a chemical weapon and unambiguous verification is still challenging. Furthermore, similar evidence can be found for exposure to chlorine gas and other, less harmful chlorinating agents. Therefore, the current study aims to use untargeted high resolution mass spectrometric analysis of chlorinated biomarkers together with machine learning techniques to be able to differentiate between exposure of plants to various chlorinating agents. Green spire (Euonymus japonicus), stinging nettle (Urtica dioica), and feathergrass (Stipa tenuifolia) were exposed to 1000 and 7500 ppm chlorine gas and household bleach, pool bleach, and concentrated sodium hypochlorite. After sample preparation and digestion, the samples were analyzed by liquid chromatography high resolution tandem mass spectrometry (LC-HRMS/MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). More than 150 chlorinated compounds including plant fatty acids, proteins, and DNA adducts were tentatively identified. Principal component analysis (PCA) and linear discriminant analysis (LDA) showed clear discrimination between chlorine gas and bleach exposure and grouping of the samples according to chlorine concentration and type of bleach. The identity of a set of novel biomarkers was confirmed using commercially available or synthetic reference standards. Chlorodopamine, dichlorodopamine, and trichlorodopamine were identified as specific markers for chlorine gas exposure. Fenclonine (Cl-Phe), 3-chlorotyrosine (Cl-Tyr), 3,5-dichlorotyrosine (di-Cl-Tyr), and 5-chlorocytosine (Cl-Cyt) were more abundantly present in plants after chlorine contact. In contrast, the DNA adduct 2-amino-6-chloropurine (Cl-Ade) was identified in both types of samples at a similar level. None of these chlorinated biomarkers were observed in untreated samples. The DNA adducts Cl-Cyt and Cl-Ade could clearly be identified even three months after the actual exposure. This study demonstrates the feasibility of forensic biomarker profiling in plants to distinguish between exposure to chlorine gas and bleach.