Ion mobility spectrometric analysis of vaporous chemical warfare agents by the instrument with corona discharge ionization ammonia dopant ambient temperature operation

The ion mobility behavior of nineteen chemical warfare agents (7 nerve gases, 5 blister agents, 2 lachrymators, 2 blood agents, 3 choking agents) and related compounds including simulants (8 agents) and organic solvents (39) was comparably investigated by the ion mobility spectrometry instrument utilizing weak electric field linear drift tube with corona discharge ionization, ammonia doping, purified inner air drift flow circulation operated at ambient temperature and pressure. Three alkyl methylphosphonofluoridates, tabun, and four organophosphorus simulants gave the intense characteristic positive monomer-derived ion peaks and small dimer-derived ion peaks, and the later ion peaks were increased with the vapor concentrations. VX, RVX and tabun gave both characteristic positive monomer-derived ions and degradation product ions. Nitrogen mustards gave the intense characteristic positive ion peaks, and in addition distinctive negative ion peak appeared from HN3. Mustard gas, lewisite 1, o-chlorobenzylidenemalononitrile and 2-mercaptoethanol gave the characteristic negative ion peaks. Methylphosphonyl difluoride, 2-chloroacetophenone and 1,4-thioxane gave the characteristic ion peaks both in the positive and negative ion mode. 2-Chloroethylethylsulfide and allylisothiocyanate gave weak ion peaks. The marker ion peaks derived from two blood agents and three choking agents were very close to the reactant ion peak in negative ion mode and the respective reduced ion mobility was fluctuated. The reduced ion mobility of the CWA monomer-derived peaks were positively correlated with molecular masses among structurally similar agents such as G-type nerve gases and organophosphorus simulants; V-type nerve gases and nitrogen mustards. The slope values of the calibration plots of the peak heights of the characteristic marker ions versus the vapor concentrations are related to the detection sensitivity, and within chemical warfare agents examined the slope values for sarin, soman, tabun and nitrogen mustards were higher. Some CWA simulants and organic solvents gave the ion peaks eluting at the similar positions of the CWAs, resulting in false positive alarms.     

Matrix-assisted laser desorption/ionization fourier transform ion cyclotron resonance mass spectrometry with pulsed in-source collision gas and in-source ion accumulation

A new matrix-assisted laser desorption/ionization (MALDI) source for Fourier transform ion cyclotron resonance mass spectrometry (FTMS) has been developed. The new source is equipped with a hexapole ion guide. The sample on the laser target is one millimeter from the hexapole ion guide, so that ions are desorbed directly into the guide. A device for pulsing collision gas in direct proximity to the laser target makes it possible to cool the ions, which have a kinetic energy spread of several electron volts when produced by the MALDI process. These ions are trapped in the hexapole where positive potentials at the laser target and at an extraction plate help trap ions along the longitudinal axis. After a pre-defined trapping time the voltage of the extraction plate is reversed and the trapped ions are extracted for transmission to the ion cyclotron resonance cell. Accumulation of ions from multiple laser shots in the hexapole before mass spectrometric analysis increases sensitivity. Preliminary sensitivity studies with substance P show that 10 attomoles of analyte applied on the target can be detected with a signal-to-noise (S/N) ratio >15.     

Using Metal Complex Ion-Molecule Reactions in a Miniature Rectilinear Ion Trap Mass Spectrometer to Detect Chemical Warfare Agents

The gas-phase reactions of a series of coordinatively unsaturated [Ni(L)_n]^y+ complexes, where L is a nitrogen-containing ligand, with chemical warfare agent (CWA) simulants in a miniature rectilinear ion trap mass spectrometer were investigated as part of a new approach to detect CWAs. Results show that upon entering the vacuum system via a poly(dimethylsiloxane) (PDMS) membrane introduction, low concentrations of several CWA simulants, including dipropyl sulfide (simulant for mustard gas), acetonitrile (simulant for the nerve agent tabun), and diethyl phosphite (simulant for nerve agents sarin, soman, tabun, and VX), can react with metal complex ions generated by electrospray ionization (ESI), thereby providing a sensitive means of detecting these compounds. The [Ni(L)_n]²⁺ complexes are found to be particularly reactive with the simulants of mustard gas and tabun, allowing their detection at low parts-per-billion (ppb) levels. These detection limits are well below reported exposure limits for these CWAs, which indicates the applicability of this new approach, and are about two orders of magnitude lower than electron ionization detection limits on the same mass spectrometer. The use of coordinatively unsaturated metal complexes as reagent ions offers the possibility of further tuning the ion-molecule chemistry so that desired compounds can be detected selectively or at even lower concentrations.

A high performance low magnetic field internal electrospray ionization-fourier transform ion cyclotron resonance mass spectrometer

A new in-magnetic field electrospray ionization (ESI) and Fourier transform ion cyclotron resonance mass spectrometer has been constructed and evaluated. This system is characterized by the use of multiple concentric cryopanels to achieve ultrahigh vacuum in the ion cyclotron resonance cell region, a probe-mounted internal ESI source, and a novel in-field shutter. Initial experiments demonstrate high resolution mass measurement capability at a field strength of 1 T. Mass resolution of 700,000 has been obtained for the 3+ charge state of Met-Lys-bradykinin (at m/z 440) generated by electrospray ionization. When electron impact ionization was employed, resolution in excess of 9,200,000 was achieved for nitrogen molecular ions (N ₂ ⁺ ). Isotopic resolution for molecular ions of bovine ubiquitin (MW=8565 µ) also was achieved by using small ion populations.     

用于化学毒剂检测的微萃取技术研究进展

对化学毒剂及其降解产物的分析检测是准确鉴别化学沾染的重要手段.由于化学毒剂及其降解产物的样品可能存在于各种基质中,且部分化学毒剂在水体等基质中降解速度过快,所以将痕量样品从复杂基质中快速高效的富集提取出来显得尤其重要.微萃取技术具有装置体积小、使用少量或不使用溶剂、绿色环保、易与色谱分析技术联用等突出优势受到广泛的关注...     

Trace level detection and identification of chemicals related to the chemical weapons convention from complex organic samples

A solid-phase extraction (SPE) method involving selective usage of solvents has been developed for trace level identification of chemical warfare agents (CWAs) present in a complex organic background. The total ion chromatograms obtained from direct gas chromatography-electron ionization mass spectrometric analysis of samples spiked with CWAs in the presence of diesel are very complex and dominated by hydrocarbon peaks and the same after treatment with SPE show distinct peaks corresponding to spiked chemicals. The recovery of samples from SPE is found to be 70-85% at the 10 ppm level.     

傅立叶变换离子回旋共振质谱法分析铝材封闭剂中的成分

该文采用傅立叶变换离子回旋共振质谱(FT-ICR-MS)技术,对一种铝材封闭剂(表面处理剂)中的未知成分进行了分析,发现了萘磺酸钠、醋酸镍、苯甲酸钠等成分。根据FT-ICR-MS测定得到的精确分子离子数据,以及同位素精细结构,推测出未知物离子分子式,再结合电感藕合等离子体质谱(ICP-MS)和气相色谱-质谱(GC-MS)分析,推断出未知成分的结构,确认其为萘磺酸钠等成分。文中还发现质谱图中有2组质量数相差62的簇离子:234.8、296.8、358.9和410.7、472.7、534.7,结合二级质谱分析,推断出这两组离子为醋酸镍与醋酸、苯甲酸加合产生的准分子离子,同时还产生二聚体、三聚体离子,合理地解析了质谱图中所出现的未知离子的归属。该研究对化工产品中未知物剖析及产品创新提供了一种新的思路和方法,并发现了镍金属离子与有机酸结合后在质谱中的离子化规律。     

Letter: New fragment ion production method using super cold electrons in electron cyclotron resonance plasma

We examined the fragmentation and ionization of molecules by low-temperature electrons generated by electron cyclotron resonance (ECR) plasma. We examined several types of metallocene compounds comprising a metal and 1,3-cyclopentadienes as ligands. We performed analyses using an ECR ion source (ECRIS) mass spectrometer. Consequently, we succeeded in ionizing fragments of an organometallic compound by adjusting the input power of the microwave introducing a super high-frequency plasma. Moreover, we succeeded in dynamically generating a significant quantity of fragment ions by continuously varying the input power. Information on the structure of a molecule may be acquired from this operation. Moreover, a molecule that could not be easily ionized thus far may now be ionizable when soft ionization is performed with this technique.     

Electron capture dissociation of substance P using a commercially available Fourier transform ion cyclotron resonance mass spectrometer

Electron capture dissociation of the peptide Substance P is reported for the first time, with an unmodified, commercially available Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. The fragmentation pattern is compared with that obtained with collisionally induced dissociation of the ions in the electrospray ion source, and note that electron capture dissociation gives a more easily interpreted spectrum, showing mainly C-fragments. With the exception of the proline residues, which require cleavage of two chemical bonds, we observe all C-fragmental we find the bias voltage of the electron gun not to be very critical.     

Solid Supported Liquid–Liquid Extraction of Chemical Warfare Agents and Related Chemicals from Water

Solid-supported liquid–liquid extraction was optimized to extract the chemical warfare agents and their non-toxic analogues from water. The developed method was compared to the conventionally used liquid–liquid extraction. This method yielded high recoveries (70–80%) of non-toxic analogues of chemical warfare agents and good recoveries (65–75%) of the nerve agent sarin and Lewisite-III. The limits of detection of non-toxic analogues of CWAs, and toxic sarin and Lewisite-III, in selected ion monitoring and full scan mode, varied from 0.01 to 0.5 μg mL^?1 and 0.1 to 1.0 μg mL^?1 respectively.     

Facility monitoring of chemical warfare agent simulants in air using an automated, field-deployable, miniature mass spectrometer

Vapors of four chemical warfare agent (CWA) stimulants, 2-chloroethyl ethyl sulfide (CEES), diethyl malonate (DEM), dimethyl methylphosphonate (DMMP), and methyl salicylate (MeS), were detected, identified, and quantitated using a fully automated, field-deployable, miniature mass spectrometer. Samples were ionized using a glow discharge electron ionization (GDEI) source, and ions were mass analyzed with a cylindrical ion trap (CIT) mass analyzer. A dual-tube thermal desorption system was used to trap compounds on 50:50 Tenax TA/Carboxen 569 sorbent before their thermal release. The sample concentrations ranged from low parts per billion [ppb] to two parts per million [ppm]. Limits of detection (LODs) ranged from 0.26 to 5.0 ppb. Receiver operating characteristic (ROC) curves are presented for each analyte. A sample of CEES at low ppb concentration was combined separately with two interferents, bleach (saturated vapor) and diesel fuel exhaust (1%), as a way to explore the capability of detecting the simulant in an environmental matrix. Also investigated was a mixture of the four CWA simulants (at concentrations in air ranging from 270 to 380 ppb). Tandem mass (MS/MS) spectral data were used to identify and quantify the individual components.     

Fluorescent molecular probes for the detection of chemical warfare agents and their mimics

Owing to their direct toxic effects on human beings, animals, and plants, chemical warfare agents (CWAs) and their mimics have become widespread in chemical warfare and agriculture. The considerable concerns about their entry into biological systems and the residues in environment stimulate the development of rapid and sensitive methods for the detection and analysis of this family of compounds. In the progress of sensitive, selective, and fast responsive detection, fluorescent molecular probes have been widely used in the detection of CWAs in recent years. Here the recent reports on the design of fluorescent molecular probes and their advantages in the detection of CWAs were reviewed. Furthermore, the extensive interests accelerate the development of novel fluorescent molecular probes and detection techniques in this field.     

Analytical separation techniques for the determination of chemical warfare agents

Today, the determination of chemical warfare agents (CWAs) is an important area of application in analytical chemistry. Chromatographic, capillary electrophoretic and mass spectrometric techniques are primarily used for the identification and quantification of a broad field of classical CWAs in environmental samples and neutralization masses, obtained after destruction of CWAs. This overview is illustrative for the state of the art and mainly focuses on the literature published since 1996.     

Real‐time trace detection and identification of chemical warfare agent simulants using recent advances in proton transfer reaction time‐of‐flight mass spectrometry

This work demonstrates for the first time the potential of using recent developments in proton transfer reaction mass spectrometry for the rapid detection and identification of chemical warfare agents (CWAs) in real‐time. A high‐resolution (m/Δm up to 8000) and high‐sensitivity (～50 cps/ppbv) proton transfer reaction time‐of‐flight mass spectrometer (PTR‐TOF 8000 from Ionicon Analytik GmBH) has been successfully used to detect a number of CWA simulants at room temperature; namely dimethyl methylphosphonate, diethyl methylphosphonate, diisopropyl methylphosphonate, dipropylene glycol monomethyl ether and 2‐chloroethyl ethyl sulfide. Importantly, we demonstrate in this paper the potential to identify CWAs with a high level of confidence in complex chemical environments, where multiple threat agents and interferents could also be present in trace amounts, thereby reducing the risk of false positives. Instantaneous detection and identification of trace quantities of chemical threats using proton transfer reaction mass spectrometry could form the basis for a timely warning system capability with greater precision and accuracy than is currently provided by existing analytical technologies. Copyright © 2009 John Wiley & Sons, Ltd.     

Mass spectrometric determination of ergosterol in a prairie natural wetland

Packed capillary liquid chromatography–electrospray mass spectrometry (LC–ESI-MS) was used for the analysis of a snow sample that was accidentally contaminated with an organophosphorus chemical warfare agent during the destruction of a chemical munition. Sarin, its hydrolysis products and a number of related compounds were identified on the basis of acquired LC–ESI-MS data. Full mass spectra were acquired for 14 compounds, with all exhibiting MH⁺, [MH+ACN]⁺ ions and/or protonated dimers that could be used to confirm molecular mass. Sampling cone voltages from 20 to 70 V were utilized with the higher sampling voltages enhancing formation of structurally important product ions in the ESI interface. All data were acquired with a time-of-flight mass spectrometer with a resolution of 5000 (50% valley definition), a resolution that aided in the assignment of elemental composition of the observed ions. The application of LC–ESI-MS to snow analysis appears to be an attractive alternative to the GC–MS methods, since both chemical warfare agents and their hydrolysis products may be analysed directly, eliminating the need for additional sample handling and derivatization steps.     

Extraction of chemical warfare agents from water with hydrophilic-lipophilic balance and C18 cartridges: comparative study

Efficient extraction of chemical warfare agents (CWAs) from water is essential before subjecting them to gas chromatographic and spectral analysis aiming towards verification of the Chemical Weapons Convention (CWC). It requires development of fast, reliable, simple and reproducible sample preparation of CWAs from water which is likely to be contaminated during deliberate or inadvertent spread of CWAs. This work describes development of a solid-phase extraction method using hydrophilic-lipophilic balance (HLB) cartridges for extraction of CWAs from water. The extraction efficiencies of HLB and C18 cartridges were compared and the results revealed that HLB sorbents performed better. Extracts were analyzed by gas chromatography-mass spectrometry. Extraction parameters, such as extraction solvent, its volume and rinsing solvent were optimized. Best recoveries of target analytes were obtained using 1mL methanol and limits of detection were achieved up to 0.05microg/mL with dichloromethane. Precision of the method was found to be less than 9.2% RSD.     

A molecular recognition platform for the simultaneous sensing of diverse chemical weapons

Chemical warfare agents (CWAs) such as phosgene and nerve agents pose serious threats to our lives and public security, but no tools can simultaneously screen multiple CWAs in seconds. Here, we rationally designed a robust sensing platform based on 8-cyclohexanyldiamino-BODIPY (BODIPY-DCH) to monitor diverse CWAs in different emission channels. Trans-cyclohexanyldiamine as the reactive site provides optimal geometry and high reactivity, allowing trans-BODIPY-DCH to detect CWAs with a quick response and high sensitivity, while cis-BODIPY-DCH has much weaker reactivity to CWAs due to intramolecular H-bonding. Upon reaction with phosgene, trans-BODIPY-DCH was rapidly converted to imidazolone BODIPY (<3 s), triggering green fluorescence with good sensitivity (LOD = 0.52 nM). trans-BODIPY-DCH coupled with nerve agent mimics, affording a blue fluorescent 8-amino-BODIPY tautomer. Furthermore, a portable test kit using trans-BODIPY-DCH displayed an instant response and low detection limits for multiple CWAs. This platform enables rapid and highly sensitive visual screening of various CWAs.

Chemical warfare agents (CWAs) such as phosgene and nerve agents pose serious threats to our lives and public security, necessitating tools that can simultaneously screen multiple CWAs in seconds.     

Mass spectrometric analysis of chemical warfare agents and their degradation products in soil and synthetic samples

A packed capillary liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method was developed for the identification of chemical warfare agents, their degradation products and related compounds in synthetic tabun samples and in soil samples collected from a former mustard storage site. A number of organophosphorus and organosulfur compounds that had not been previously characterized were identified, based on acquired high-resolution ESI-MS data. At lower sampling cone voltages, the ESI mass spectra were dominated by protonated, sodiated and protonated acetonitrile adducts and/or their dimers that could be used to confirm the molecular mass of each compound. Structural information was obtained by inducing product ion formation in the ESI interface at higher sampling cone voltages. Representative ESI-MS mass spectra for previously uncharacterized compounds were incorporated into a database as part of an on-going effort in chemical warfare agent detection and identification. The same samples were also analyzed by capillary column gas chromatography (GC)-MS in order to compare an established method with LC-ESI-MS for chemical warfare agent identification. Analysis times and full-scanning sensitivities were similar for both methods, with differences being associated with sample matrix, ease of ionization and compound volatility. GC-MS would be preferred for organic extracts and must be used for the determination of mustard and relatively non-polar organosulfur degradation products, including 1,4- thioxane and 1,4-dithiane, as these compounds do not ionize during ESI-MS. Diols, formed following hydrolysis of mustard and longer-chain sulfur vesicants, may be analyzed using both methods with LC-ESI-MS providing improved chromatographic peak shape. Aqueous samples and extracts would, typically, be analyzed by LC-ESI-MS, since these analyses may be conducted directly without the need for additional sample handling and/or derivatization associated with GC-MS determinations. Organophosphorus compounds, including chemical warfare agents, related compounds and lower volatility hydrolysis products may all be determined during a single LC-ESI- MS analysis. Derivatization of chemical warfare agent hydrolysis products and other compounds with hydroxyl substitution would be required prior to GC-MS analysis, giving LC-ESI-MS a definite advantage over GC-MS for the analysis of samples containing chemical warfare agents and/or their hydrolysis products.     

Study of the fragmentation mechanism of novel functionalized macrocycles by Fourier transform ion cyclotron resonance mass spectrometry

Liquid secondary ion mass spectrometry (L-SIMS) of six new functionalized macrocycles was investigated. All six compounds yielded abundant fragment ions and protonation molecular ions [M + H](+) under L-SIMS conditions. The proposed fragmentation mechanisms were supported by high-resolution accurate mass data from Fourier transform ion cyclotron resonance mass spectrometric and MS(n) experiments on using sustained off-resonance irradiation collision-induced dissociation.     

Water adsorption with hysteresis effect onto microporous activated carbon fabrics

Understanding the adsorption of water vapor onto activated carbons is important for designing processes to remove dilute contaminants from humid gas streams, such as providing protection against chemical warfare agents (CWAs), or against toxic industrial compounds (TICs) used in a terrorist chemical attack. Water vapor isotherms for Calgon BPL granular activated carbon (GAC), military ASZM-TEDA GAC, electrospun activated carbon nanofibers (ACnF), Calgon Zorflex^™ activated carbon cloth, and Novoloid-based activated carbon fiber cloth (ACFC) are presented. Of particular interest are the ACFC isotherms, which exhibit an unusually high degree of hydrophobicity. The ACFC isotherms also show a correlation between water vapor adsorption hysteresis and the level of activation. Water vapor isotherm models from the literature are compared.