Sulfur Mustard (SM) is a potent vesicant chemical agent with profound and complex toxic effects. Traditionally, its toxic mechanism has been attributed to DNA alkylation-induced cytotoxicity and genomic instability. However, growing evidence indicates that dysregulation of epigenetic regulatory mechanisms constitutes a central link in SM toxicity, particularly in its long-term and delayed effects. Our study establishes an in vitro SM exposure model and employs integrated multi-omics profiling-including six histone modifications, DNA methylation, transcriptomic, and non-coding RNA analyses-to systematically investigate SM-induced epigenetic reprogramming. Our results demonstrate that SM drives extensive chromatin state remodeling, accompanied by altered expression of genes involved in DNA damage repair, cell cycle regulation, and immune response. We further constructed a predicted ceRNA network, identifying key lncRNAs, potentially associated with promoter hypomethylation, that may participate in ceRNA interactions involving cancer- and apoptosis-related genes. Additionally, we developed and validated a mass spectrometry-based method for precise quantification of 37 histone H3 modifications, providing a robust tool for profiling epigenetic biomarkers of exposure. These findings provide systems-level evidence for acute epigenetic reprogramming induced by SM exposure and reveal relevant associations between epigenomic dysregulation and genomic instability-related pathways in keratinocytes, suggesting candidate targets for future functional validation and early intervention studies.

The increasing frequency of castor bean or ricin-induced intoxication or terror events threatens public safety and national security, making the tracing of castor bean origins critical for law enforcement and counterterrorism efforts. Chemical attribution signatures (CAS) could address this issue by providing inherent and forensic links between ricin-containing samples and their geographical origins; however, practical implementations of this approach remain scarce. Omics data sets offer substantial potential to generate comprehensive biological insights and high-dimensional data for provenance attribution, where transcriptomics and proteomics profiling are better suited to castor beans than traditional genomics and metabolomics, regarding that castor beans exhibit low genetic diversity but high phenotypic polymorphism. In this work, toward castor bean samples from 14 provinces or autonomous regions in China and three international locations, including Ethiopia, Pakistan, and South Sudan, we proposed an integrated local-global data-mining strategy by systematically integrating RNA-seq transcriptomics and data-independent acquisition quantitative proteomics, and developed a straightforward feature-screening pipeline to prioritize 59 signature peptides as provenance-related CAS with distinct interregional and international expression patterns. A subsequent machine learning model trained on these CAS achieved 93.7% classification accuracy, identifying robust discriminative patterns among samples from different global regions, as well as fine-scale differences across altitude gradients and north-south divisions in China, in which the attribution index of altitude and latitude is reported for the first time. Finally, after validation by parallel reaction monitoring in nanoLC-HRMS/MS, we confirmed a minimum signature panel of 24 peptides as molecular CAS markers for the origin attribution of castor beans.

Nucleic acids are one of the key cellular targets for chemical exposure and stress responses, and nucleic acid modification induced by chemical toxicants represents a core research area in toxicology. Toxicant-induced nucleic acid modifications are categorized into two interconnected pathways. First is the exogenous modifications arising from direct covalent or noncovalent interactions between toxicants or their reactive metabolites and nucleic acids. Second is the endogenous modifications generated secondarily through toxicant-triggered oxidative stress, lipid peroxidation, inflammation, endogenous alkylation, and epigenetic or epitranscriptomic dysregulation. Taking prototypical electrophilic agents, chemical warfare agents (CWAs), as the focal point, this review maps a comprehensive landscape of nucleic acid modification induced by CWAs, mainly including exogenous monoadducts, cross-links, and endogenous oxidative damage and regulatory modifications. We systematically elucidate the chemical reactivity, structural diversity, and toxicokinetic behaviors of key lesions, further exploring the differential roles of these lesions as exposure or effect biomarkers and their contribution to adverse biological outcomes induced by CWAs. For different CWAs, bifunctional reactions producing DNA-DNA and DNA-protein cross-links constitute the most cytotoxic lesions, and single-base adducts represent the predominant and best-characterized modifications. In this context, nucleic acid adductomics has emerged as an untargeted strategy for comprehensively profiling diverse induced lesions at the molecular level. Mass spectrometry (MS) serves as the core analytical platform for adductomics, enabling structural identification and accurate picogram-level quantification of nucleic acid adducts. Meanwhile, next-generation sequencing (NGS) achieves high-resolution localization of endogenous modifications in certain contexts, although its applicability to bulky and chemically complex lesions remains technically challenging. It is expected that the combination of MS and NGS will unlock the capability to dissect the inherent relationship between specific modification sites, gene function perturbation, and resultant toxicological effects.

Ricin is a highly lethal plant-derived biotoxin posing severe threats to public security and necessitating rapid, sensitive, and on-site detection methods. To overcome the inherent batch-to-batch variability of traditional antibodies, synthetic peptides have emerged as promising alternative recognition elements. Herein, we report a de novo screening and surface plasmon resonance (SPR)-guided affinity maturation of novel anti-ricin cyclononapeptides for the development of a highly sensitive fluorescent lateral flow assay (LFA). Through a virtual-experimental iterative strategy integrating phage display, in silico molecular docking, alanine/histidine scanning, and double-site saturation mutagenesis, we evolved an optimum variant cyclopeptide (F7) with a 100-fold enhanced binding affinity (KD = 165 nM). Based on F7, we constructed two novel sandwich LFAs involving cyclopeptide-monoclonal antibody (mAb) or cyclopeptide-glycoprotein using time-resolved fluorescent microspheres as sensitive signal reporters. Facilitated by a self-developed ultracompact handheld reader, this optimized LFA achieved a high sensitivity of 0.1 ng/mL without requiring complicated signal amplification. Crucially, the developed LFA method demonstrated excellent matrix tolerance, enabling reliable semi-quantification of trace ricin in complex authentic samples, including human plasma, beverages, castor plant tissues, and suspected white powder mixtures. Combined with the self-developed ultracompact handheld LFA reader, the LFA platform exhibited satisfactory capture efficiency in simulated bioterrorism surface-swabbing scenarios. It is expected that this field-deployable, high-performance LFA platform could prove instrumental in the rapid risk assessment, on-site screening of complex environmental matrices, and emergency monitoring of severe biological hazards.

Synthesis route attribution enables accurate source tracing of chemical warfare agents and effective discrimination between distinct synthetic pathways. In the current study, we report for the first time the identification of trace process-related impurities derived from the synthesis of the vesicant ethyl sesquimustard, which is listed in Schedule 1.A.04 of the Chemical Weapons Convention (CWC). Using 1,2-ethanedithiol and 2-mercaptoethanol as precursors, 22 different synthetic routes were designed, and 88 batches of samples were produced through micro-synthesis. Gas chromatography-high resolution mass spectrometry (GC-HRMS) coupled with a non-targeted screening strategy was employed to analyze route-specific compounds. The obtained dataset was further used to train the orthogonal partial least squares discriminant analysis algorithm and generate a classification model consisting of eight sub-models. The verification results showed that the overall classification accuracy of the model was 21/22 (about 95%).

Alkylthiophosphonates, listed in Schedule 2.B.04 of the Chemical Weapons Convention, are key environmental markers and stable degradation products of V-series nerve agents. However, their reliable identification is hampered by some fundamental challenges: over one million theoretical structures are possible, whereas standard reference databases contain only a limited number of entries. This disparity highlights the need for high-throughput, nontargeted screening strategies capable of detecting compounds beyond library coverage. Previous research has indicated that liquid chromatography-mass spectrometry shows limited sensitivity for sulfur-rich analogues, exhibiting an exponential signal attenuation as the number of sulfur atoms increases. To address these gaps, a set of over 100 typical compounds was synthesized and their fragmentation behaviors were systematically investigated using gas chromatography-high resolution mass spectrometry. The analysis revealed that McLafferty (+1) rearrangement and α-cleavage are the dominant mechanisms generating their characteristic fragment ions. Building on these mechanistic insights and leveraging the complementary strengths of electron ionization and chemical ionization, 33 groups of alerting ions and 171 theoretical accurate masses were derived. These were used to construct a nontargeted screening strategy for millions of alkylthiophosphonates. The strategy was successfully applied to identify unknown chemicals in authentic samples, enabling effective discrimination between phosphonothiolate/phosphonothionate and phosphonodithiolate/phosphonothiolothionate isomeric pairs. The method demonstrated high sensitivity, with limits of detection as low as 1-10 ppb, along with good repeatability. These results confirm the practical utility of the developed strategy for the verification and monitoring of alkylthiophosphonates in environmental and forensic contexts.

The practical verification analysis of chemical warfare agents, notably the G-series organophosphorus nerve agents, and their related chemicals─including precursors, byproducts, and degradation products─is critical not only for attributing the use of chemical weapons but also for retrospection of illicit production networks and gathering crucial forensic evidence. However, this task is significantly challenged by the vast "chemical space explosion" of potential analogues and the limitations of conventional database-dependent methods, necessitating high-throughput nontargeted screening approaches. In this study, following systematic characterization of fragmentation pathways and characteristic ions through integration of mass spectral libraries and clustering analysis, an integrated dual-ion source nontargeted screening strategy based on gas chromatography high-resolution mass spectrometry was established for the identification of unknown nerve agents and their related chemicals. Under electron ionization mode, a set of 52 specific "Alerting Ions" and 12 types of structures was established and applied for the rapid screening and classification of millions of suspected compounds. These candidates, after being located via retention index, were further verified under chemical ionization mode through Kendrick Mass Defect analysis of their molecular ions. Plausible structures were proposed through comprehensive spectral interpretation, and the candidate list was significantly refined using an RI prediction model. Final confirmation was achieved by comparison with reference standards. This strategy was validated using 73 home-synthesized compounds and exhibited a low limit of detection of 10-50 ng/mL. It was successfully applied to the analysis of environmental authentic samples from the Organization for the Prohibition of Chemical Weapons.

Identifying diverse, uncharacterized plant-derived nerve agent adducts is a formidable challenge for environmental exposure confirmation and forensic attribution. We developed a fragmentation pattern-driven nontargeted screening strategy integrating in-source fragmentation with Full MS, all-ion fragmentation (AIF), and neutral loss (NL)-triggered ddMS2 acquisition. By utilizing agent-specific neutral losses and diagnostic fragment ions, 256 tentative adduct-related features were identified across four nerve agents and four plant species, establishing an expansive repository of previously unreported candidate markers. Structural characteristics and preferential adduction sites were elucidated through integrated interpretation of high-resolution MS data, fragmentation pathways, and density functional theory calculations. Notably, 9 features exhibited conservation across plant species, while 11 features remained detectable at low-level exposure in Arabidopsis thaliana, highlighting their potential as viable markers. This strategy expands the detectable chemical space for plant-derived nerve agent adducts and provides a transferable framework for environmental exposure assessment and emerging contaminants research.

C18 (up)-graphitized carbon (down) solid-phase extraction disks were used for the first time to simultaneously and rapidly enrich 35 dissolved marine algal toxins (MATs) from seawater, with a maximum difference in log Kow values of 12.3. The enriched MATs were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The flow rate of the pretreatment process was 100 mL/min, and a 2000-fold enrichment was achieved for seawater, with recoveries of the target MATs exceeding 65.9%. The developed method demonstrated high sensitivity and excellent precision, with limits of detection as low as 2.0 × 10-4 ng/L and average relative standard deviations ≤12.8%. Real seawater samples from Liaodong Bay and Beibu Bay were analyzed using this method to detect dissolved MATs. Nine MATs, including gymnodimine, pectenotoxin-2, okadaic acid (OA), 19-epi-OA, dinophysistoxin-1 (DTX1), 19-epi-DTX1, homo-yessotoxin, gonyautoxin-2 (GTX2), and GTX3, were detected in seawater samples from the selected research areas. Notably, 19-epi-OA and 19-epi-DTX1 were identified for the first time in China. The concentrations of dissolved ∑MATs in Liaodong Bay and Beibu Bay ranged from 26.12 to 56.95 ng/L and 28.12 to 51.98 ng/L, respectively. This study proposes a potential technique for exploring the distribution characteristics of multiple MATs across large-scale coastal seawater.

Development of efficient and rapid detection technologies for organophosphorus nerve agents (OPNAs) is of great significance for public safety, ecological environment and medical treatment. Immunochromatographic test strips offer advantages including rapid detection, simple operation, and easy result interpretation, making them widely used in fields such as biosafety, food safety, and poisoning diagnosis. In present study, 10 haptens for five important organophosphorus nerve agents (OPNAs), including GD, GF, GB, VX and A234, were designed and prepared by computational chemistry and molecular dynamics simulation. The results showed that increasing the rigidity of haptens could enhance the immune response, promote initial binding and activation of B cells, and significantly improve the titer and affinity of antibody from 100 ng/mL to 2 ng/mL. The detection limits of the optimized test strips for GF, A234, VX, GD and GB were 2, 5, 10, 20 and 100 ng/mL, respectively. In addition, they can be directly used for rapid and high-sensitivity detection in various substrates collected from different exposure scenarios. As we know, this study is the first to detect GF, A234 and VX using immunochromatographic test strips and demonstrate the lowest detection limit.

Organophosphorus nerve agents are the most threatening chemical warfare agents and terrorist agents.The number of nerve agents and their related chemicals involved in the verification of Chemical Weapon Convention(CWC)exceeds ten million,with the majority being isomers.Accurate structural identification of these chemicals has always been one of the challenges in CWC related verification analysis.In this work,a total of 17 kinds of alkyl phosphonate isomers and structural analogs from 5 groups were designed and synthesized,and then analyzed by gas chromatography-mass spectrometry(GC-MS)and gas chromatography-infrared spectroscopy(GC-FTIR).The spectra of isomers or structural analogs obtained from two techniques as well as the structural information provided therein were compared and analyzed.The results showed that for isomers or structural analogs with similar MS spectra,FTIR spectra could provided more structural fingerprint information of compounds and had advantages in confirming structures.Combined with the excellent separation ability of GC,GC-FTIR can be used to assist GC-MS in the structural confirmation of alkyl phosphates,achieving rapid and accurate identification of isomers or structural analogues.

Monophosphorylation is a key rate-limiting step for the efficacy of broad-spectrum nucleoside antiviral drugs, and designing phosphate prodrugs is an effective method to enhance antiviral efficacy. N4-hydroxycytidine (NHC) has a broad-spectrum antiviral effect. Based on the mechanism of action and metabolic inactivation characteristics of NHC, we designed a series of dual ester prodrugs targeting the N4-hydroxyl group and the 5'-phosphate of the ribose ring. Twenty-nine compounds were designed and synthesized. The cytotoxicity assay results showed low cytotoxicity (no significant toxicity at 160 μM). Using the Vesicular Stomatitis Virus expressing Green Fluorescent Protein (VSV-GFP) virus screen, it was found that all of them have antiviral activity. Compounds 2328 and 2322 showed better antiviral activity than molnupiravir. The EC50s of 2328 against VSV, HMPV-A2, and RSV-A2 viruses were 2.19 μM, 35.6 μM, and 53.5 μM, respectively, and the EC50s of 2322 against VSV, HMPV-A2, and RSV-A2 were 6.23 μM, 52.8 μM, and 28.2 μM, respectively. Structure-activity relationships indicate that the antiviral activity of compounds at the cellular level is closely linked to the structure of the prodrug's phosphate ester, whereas the ester group on the N4-hydroxyl is more tolerant of diverse functional groups.

Decontamination is one of the most effective ways to reduce the hazards of different sulfur mustards. Herein, reactions of various sulfur mustards with four classic decontaminant agents were investigated and their products identified by UPLC-MS/HRMS and GC-MS. Quantitative determinations of individual products in the reaction mixture allows to evaluate the kinetic parameters of the mustard reactions. The degradation rate of 1,2-bis(2-chloroethylthio) ethane and bis(2-chloroethylthioethyl) ether is obviously faster than that of sulfur mustard (SM), but the degradation rate of bis(2-chloroethylthio) methane and bis(2-chloroethylthiomethyl) ether is slower than that of SM. Degradation occurred in a nucleophilic substitution reaction between 2,3-butanedione monoximate, sodium phenolate, and with susceptible sites in the mustards. DS2 mainly exerts its degradation function by elimination reactions. However, 2,3-monoximate degrades sulfur mustards through nucleophilic substitution and elimination reaction. Based on the results of quantumchemical calculations, we assume that the difference of the decontamination rate may be related to the electrostatic potential energy of mustards itself.

Accurate detection of endogenous miRNA modifications, such as N6-methyladenosine (m6A), 7-methylguanosine (m7G), and 5-methylcytidine (m5C), poses significant challenges, resulting in considerable uncertainty regarding their presence in mature miRNAs. In this study, we demonstrate for the first time that liquid chromatography coupled with a tandem mass spectrometry (LC-MS/MS) nucleoside analysis method is a practical tool for quantitatively analyzing human miRNA modifications. The newly designed liquid-solid two-step hybridization (LSTH) strategy enhances specificity for miRNA purification, while LC-MS/MS offers robust capability in recognizing modifications and sufficient sensitivity with detection limits ranging from attomoles to low femtomoles. Therefore, it provides a more reliable approach compared to existing techniques for revealing modifications in endogenous miRNAs. With this approach, we characterized m6A, m7G, and m5C modifications in miR-21-5p, Let-7a/e-5p, and miR-10a-5p isolated from cultured cells and observed unexpectedly low abundance (<1% at each site) of these modifications.

The changes in epigenetic modifications of histones are one of the important factors in cancer development and metastasis, and the development of epigenetic therapies for cancer treatment has led to epigenetic drug screening as a research focus. In this work, the common methylation and acetylation modifications at the N -terminal of cellular histones H3 were quantified by a liquid chromatography -tandem mass spectrometry (LC -MS/ MS) method, and a throughput assay for screening and assessment of epigenetic drug was established. A total of 39 kinds of modification combinations containing common methylation and acetylation sites of H3 peptides were simultaneously monitored by triple quadrupole mass spectrometry in multiple reaction monitoring (MRM) mode. The developed method was applied to analyze HepG2 cells exposed for 24 h to 28 kinds of epigenetic drugs that could modulate the level of methylation or acetylation modifications. Results showed that 25 of these drugs, such as deacetylase inhibitors Abexinostat, Valproic acid and AGK7, induced histone H3 modification changes in the exposed cells that were consistent with those reported in the literature, while other modification changes were also detectable. Three of these drugs, including demethylase inhibitors IOX1, GSK-jl and acetyltransferase inhibitor L002, however, induced modification changes different from those reported in the literature. An overall test match rate of 89.3% was achieved. The established LC-MS/MS method could quantitatively analyze histone H3 modification sites and their changes in cells in a high -throughput and highly sensitive manner, and could be applied to the evaluation of epigenetic drugs with known activities, with good specificity and rich modification information, which was expected to provide a new technological tool for screening and evaluation of epigenetically active compounds and exploration of their mechanism of action.

BACKGROUND:Dichlorvos (DDVP) is an efficient and highly toxic organophosphorus pesticide. Considering its effects on human health and ecosystems, pesticide residue and pollution monitoring is of great significance. Traditional methods like chromatography with mass spectrometry are not portable or rapid because they use large instruments and complex pre-processing methods. Compared with other optional on-site detection technologies, like enzymatic and antibody methods, aptamers are advantageous because they are stable, readily modified, and inexpensive. Therefore, screening and developing a specific adapter for DDVP detection is necessary and will be of practical value. RESULTS:We screened, modified, and compared two dual-labeled aptamer probes (Cy3-DV55-Cy5 and Cy3-DV65-Cy5). The kinetics studied showed that 5 min was sufficient for the detection reaction. Both aptamers showed selectivity for DDVP but DV55 was superior to DV65. To research the binding stabilities and the mechanism between the aptamers and DDVP, the secondary structures, melting temperatures, fluorescence quenching types, and constants were investigated. Which showed that DV55 was specific for DDVP and showed better binding than DV65. Comparison of the UV absorption and FRET for DV55 and the truncated structures suggested that loop 3 in DV55 might play an important role in the binding of DV55 to DDVP. The Cy3-DV55-Cy5 aptamer had a linear range of 0-100 μM for DDVP detection and the limit of detection was 150 nM. Simulated pesticide residue detection experiments showed that the method was simple, fast, and had acceptable recovery (89.8%-105.2 %). SIGNIFICANCE:Pesticide detection is important but on-site detection methods are usually not portable or rapid. We developed two dual-labeled aptamer probes that could feasibly be practically applied to rapid on-site DDVP detection of pesticide residues and pollutants. This research provides experimental and theoretical data for the development and design of similar pesticide probes.

Snake venom is a complex mixture secreted from the glands of poisonous snakes， which contains proteins， peptides， lipids， nucleosides， sugars， amino acids， amines， metal ions， and other components. According to the toxicological classification， snake venoms can be classified as neurotoxins， anticoagulants and procoagulant toxins， cardiac toxins， other toxin proteins， and enzymes. Proteins and peptides are the key components of snake venom. The establishment of rapid， accurate analysis and identification methods for proteins in snake venom is a prerequisite for snake venom-related forensic identification， intoxication events， and pharmaceutical development. Until now， the classical analysis and identification methods have mainly been biochemical or immunoassays for DNA or proteins， such as polymerase chain reaction， agglutination test， enzyme-linked immunosorbent assay， fluorescent immunoassay， and various biosensing approaches. These methods have some limitations such as a high false-positive ratio， low sensitivity， poor anti-interference ability， and limited species discrimination capability. In recent years， with the rapid development of mass spectrometry （MS） techniques， the proteomics of snake venom has also attracted much attention and has contributed to the identification of snake species， in which non-targeted and targeted proteomics represent two main divisions. However， species identification via proteomics is in its infancy in forensic science. First， the tandem MS spectra of peptide sequences are highly complex， which poses a great challenge for the strict and accurate matching of peptides based on the rational speculation of MS fragmentation rules and theoretical calculations in non-targeted proteomics. Second， for the confirmation and identification of unknown substances， reference substances are commonly needed， but those for snake venom are lacking. Proteomics in snake venom identification is still in progress to improve the identification confidence and clarify the identification rules. In this work， a method based on nano-ultra-high performance liquid chromatography-quadrupole-orbitrap high-resolution mass spectrometry （Nano LC-MS/HRMS） and size exclusion chromatography （SEC） was developed for identifying proteins and their source species， with strict rules for five suspected snake venom samples and their contamination in one case. Three SEC elution peaks were obtained from each of the five samples， which were lyophilized and treated with trypsin in solution， and then separated and analyzed by Nano LC-MS/HRMS. First， the Full MS/dd MS2 mode was used for the non-targeted acquisition of peptide information in the samples， and after submission to the Swiss-Prot database， the protein databases of Serpentes， Colubroidea， Elapidae， Elapinae， and Naja were contracted stepwise and compared. A total of 32 proteins from Naja atra were identified under the conditions of both peptide spectrum match and false discovery rate less than 1%， and number of characteristic peptides greater than or equal to two. All of these were derived from ten families of Naja atra， mainly three-finger toxins， metalloproteinases， and phospholipase A2. Proteins D3TTC2， D5LMJ3， Q7T1K6， Q9DEQ3， and Q9YGI4 were the most common among the five samples. Finally， the parallel reaction monitoring mode was adopted to select two unique peptides for each protein for targeted verification. It was considered that a protein in the samples was truly identified when it met the strict standard "the Δm/z of at least 75% y+ and b+ ions of each unique peptide was less than 5 ppm". After these consequently procedures， we identified that all five samples contained the venom of the Naja atra. Our identification method is a systematic and strict example that can provide effective technical support for the forensic identification of snake venom poisoning， as well as for pharmaceutical development toward snake venoms.

Alkylation reagents, represented by sulfur mustard (SM), can damage DNA molecules directly as well as lead to oxidative stress, causing DNA lesions indirectly. Correspondingly, two types of biomarkers including alkylated DNA adducts and oxidative DNA adducts are commonly involved in the research of DNA damage evaluation caused by these agents. However, the correlations and differences of the occurrence, duration, severity, and traceability between alkylation and oxidation lesions on the DNA molecular level reflected by these two types of biomarkers have not been systematically studied. A simultaneous determination method for four alkylated DNA adducts, i.e., N7-(2-hydroxyethylthioethyl)2'-guanine (N7-HETEG), O6-(2-hydroxyethylthioethyl)-2'-guanine (O6-HETEG), N3-(2-hydroxyethylthioethyl)-2'-adenine (N3-HETEA), and bis(2-ethyl-N7-guanine)thioether (Bis-G), and the oxidative adduct 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in urine samples by isotope-dilution high-performance liquid chromatography-tandem mass spectrometry (ID-HPLC-MS/MS) was built with a lower limit of detection of 0.02 ng/mL (except Bis-G, 0.05 ng/mL) and a recovery of 79-111%. The profile of these adducts was simultaneously monitored in urine samples after SD rats' dermal exposure to SM in three dose levels (1, 3, and 10 mg/kg). The time-effect and dose-effect experiments revealed that when exposed to SM, DNA alkylation lesions would happen earlier than those of oxidation. For the two types of biomarkers, alkylated DNA adducts showed an obvious dose-effect relationship and could be used as internal exposure dose and effect biomarkers, while 8-OH-dG did not show a correlation with exposure dose, demonstrating that it was more suitable as a biomarker for DNA oxidative lesions but not an indicator for the extent of cytotoxicity and internal exposure.

Many traditional Chinese herbs contain pyrrolizidine alkaloids (PAs), which have been reported to be toxic to livestock and humans. However, the lack of PAs standards makes it difficult to effectively conduct a risk assessment in the varied components of traditional Chinese medicine. It is necessary to propose a suitable strategy to obtain the representative occurrence data of PAs in complex systems. A comprehensive approach for annotating the structures, concentration, and mutagenicity of PAs in three Chinese herbs has been proposed in this article. First, feature-based molecular networking (FBMN) combined with network annotation propagation (NAP) on the Global Natural Products Social Molecular Networking web platform speeds up the process of annotating PAs found in Chinese herbs. Second, a semi-quantitative prediction model based on the quantitative structure and ionization intensity relationship (QSIIR) is used to forecast the amounts of PAs in complex substrates. Finally, the T.E.S.T. was used to provide predictions regarding the mutagenicity of annotated PAs. The goal of this study was to develop a strategy for combining the results of several computer models for PA screening to conduct a comprehensive analysis of PAs, which is a crucial step in risk assessment of unknown PAs in traditional Chinese herbal preparations.

The Chemical Weapons Convention (CWC) requires verification of a large number of compounds with different types and properties. The results of the verification are of great political and military sensitivity. However, the sources of verification samples are complex and diverse, and the contents of the target compounds in these samples are usually very low. These issues increase the likelihood of missed or false detection. Thus, establishing rapid and effective screening methods for the accurate identification of CWC-related compounds in complex environmental samples are of great importance. In this study, a fast and simple procedure based on headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-electron ionization mass spectrometry (GC-EI/MS) in full-scan mode was developed to determine CWC-related chemicals in oil matrix. A total of 24 CWC-related chemicals with different chemical characteristics were selected to simulate the screening procedure. The selected compounds were divided into three groups based on their properties. The first group included volatile and semi-volatile CWC-related compounds with relatively low polarity, which could be extracted by HS-SPME and directly analyzed by GC-MS. The second group included moderately polar compounds with hydroxyl or amino groups; such compounds are related to nerve, blister, and incapacitating agents. The compounds in the third group included non-volatile CWC-related chemicals with relatively strong polarity, such as alkyl methylphosphonic acids and diphenyl hydroxyacetic acid. These compounds must be derivatized into vaporizable derivatives prior to extraction by HS-SPME and analysis by GC-MS. Variables that influence the SPME process, such as fiber type, extraction temperature and time, desorption time, and derivatization protocol, were optimized to improve the sensitivity of the method. The screening procedure for CWC-related compounds in the oil matrix samples included two main steps. First, low-polarity volatile and semi-volatile compounds (i. e. the first group) were extracted by HS-SPME with divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fibers and analyzed in split-injection mode (split ratio, 10∶1) using GC-MS. The use of a large split ratio can reduce the solvent effect, which is conducive to the detection of low-boiling-point compounds. If necessary, the sample could be extracted once more and analyzed in splitless mode. The derivatization agent bis(trimethylsilyl)trifluoroacetamide (BSTFA) was then added to the sample. Mid- and high-polarity compounds (i. e. the second and third groups) were extracted with polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibers after derivatization and analyzed in splitless mode using GC-MS. The established method exhibited good repeatability and sensitivity. The detection limits for the compounds in the first group ranged from 0.5 ng/mL to 100 ng/mL, whereas the detection limits for the compounds in the second and third groups ranged from 20 ng/mL to 300 ng/mL. Except for compounds with extremely high boiling points and a few compounds that are not suitable for derivatization with BSTFA, the method can be used to analyze most CWC-related compounds in oil matrix samples. In particular, it greatly shortened the preparation time of the oil matrix samples and reduced the loss of low-boiling-point compounds owing to the sample concentration process, thereby avoiding missed detection. The method was successfully applied to the Organization for the Prohibition of Chemical Weapons (OPCW) proficiency tests and proved to be a useful technique for the rapid screening of trace levels of CWC-related chemicals in oil matrix.