RESUMEN

During the World Wars large quantities of phenylarsenic chemical warfare agents (CWAs) were dumped in the Baltic Sea. Many transformation products of these chemicals have been identified, but the pathways that produce the found chemicals has not been investigated. Here we studied the biotic and abiotic transformation of phenylarsenic CWAs under oxic and anoxic conditions and investigated how the sediment bacterial communities are affected by CWA exposure. By chemical analysis we were able to identify seventeen CWA-related phenylarsenicals, four of which (methylphenylarsinic acid (MPAA), phenylthioarsinic acid (PTAA), phenyldithioarsinic acid (PDTAA) and diphenyldithioarsinic acid (DPDTAA)) have not been reported for marine sediments before. For the first time PTAA was verified from environmental samples. We also observed equilibrium reactions between the found transformation products, which may explain the occurrence of the chemicals. 16S rRNA-analysis showed that bacterial communities in sediments are affected by exposure to phenylarsenic CWAs. We observed increases in the amounts of arsenic-resistant and sulphur-metabolising bacteria. Different transformation products were found in biotic and abiotic samples, which suggests that bacteria participate in the transformation of phenylarsenic CWAs. We propose that methylated phenylarsenicals are produced in microbial metabolism and that chemical reactions with microbially produced sulphur species form sulphur-containing transformation products.

Asunto(s)

Arsénico , Sustancias para la Guerra Química , Contaminantes Químicos del Agua , Sustancias para la Guerra Química/toxicidad , ARN Ribosómico 16S/genética , Contaminantes Químicos del Agua/análisis , Arsénico/análisis , Azufre , Sedimentos Geológicos/análisis

RESUMEN

A sampling, modulation, and separation (SMS) unit was tested for detection of hazardous chemicals. The SMS unit, designed and developed for on-site sampling and analysis, consists of a dynamic inlet system coupled with a fast, miniaturized gas chromatograph (GC). Feasibility of the SMS unit was evaluated together with a hazardous chemical vapor generator. The performance of the SMS unit was tested with automated thermal desorption after SMS to collect samples for GC-mass spectrometry (GC-MS) measurements. Detection of sarin nerve agent was verified. Additionally, the vapor generator was connected to the SMS unit, which was hyphenated with a photoionization detector (PID), thus creating a fast GC-PID system. This system gave a positive response for degradation products of sulfur mustard, thereby indicating suitability of the SMS-PID unit for field drone applications.

Asunto(s)

Sustancias Peligrosas/química , Sustancias Peligrosas/aislamiento & purificación , Espectrometría de Masas/métodos , Miniaturización/métodos , Temperatura , Factores de Tiempo , Volatilización

RESUMEN

Previously unknown phenylarsenic chemicals that originated from chemical warfare agents (CWAs) have been detected and identified in sediment samples collected from the vicinity of chemical munition dumpsites. Nontargeted screening by ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) was used for detection of 14 unknown CWA-related phenylarsenic chemicals. Methylated forms of Clark I/II, Adamsite, and phenyldichloroarsine were detected in all analyzed sediment samples, and their identification was based on synthesized chemicals. In addition, other previously unknown CWA-related phenylarsenic chemicals were detected, and their structures were elucidated using MS/HRMS technique. On the basis of relative isotope ratios of protonated molecules and measures of exact masses of formed fragment ions, it could be concluded that some of these unknown chemicals contained a sulfur atom attached to an arsenic atom. In addition to that, some of the samples contained chemicals that had formed via addition of an OH group to the aromatic ring. However, it is not possible to say how these chemicals are formed, but the most plausible cause is activities of marine microbes in the sediment. To our knowledge, these chemicals have not been detected from sediment samples previously. Sensitive analytical methods are needed for these novel chemicals to assess the total CWA burden in marine sediments, and this information is essential for the risk assessment.

Asunto(s)

Arsenicales/análisis , Sustancias para la Guerra Química/análisis , Sedimentos Geológicos/análisis , Cromatografía Líquida de Alta Presión , Estructura Molecular

RESUMEN

Here we demonstrate a novel homogeneous one-step immunoassay, utilizing a pair of recombinant antibody antigen-binding fragments (Fab), that is specific for HT-2 toxin and has a positive readout. Advantages over the conventional competitive immunoassay formats such as enzyme-linked immunosorbent assay (ELISA) are the specificity, speed, and simplicity of the assay. Recombinant antibody HT2-10 Fab recognizing both HT-2 and T-2 toxins was developed from a phage display antibody library containing 6 × 10(7) different antibody clones. Specificity of the immunoassay was introduced by an anti-immune complex (IC) antibody binding the primary antibody-HT-2 toxin complex. When the noncompetitive immune complex assay was compared to the traditional competitive assay, an over 10-fold improvement in sensitivity was observed. Although the HT2-10 antibody has 100% cross-reactivity for HT-2 and T-2 toxins, the immune complex assay is highly specific for HT-2 alone. The assay performance with real samples was evaluated using naturally contaminated wheat reference material. The half-maximal effective concentration (EC50) value of the time-resolved fluorescence resonance energy transfer (TR-FRET) assay was 9.6 ng/mL, and the limit of detection (LOD) was 0.38 ng/mL (19 µg/kg). The labeled antibodies can be predried to the assay vials, e.g., microtiter plate wells, and readout is ready in 10 min after the sample application.

Asunto(s)

Inmunoensayo , Toxina T-2/análogos & derivados , Anticuerpos Monoclonales/inmunología , Transferencia Resonante de Energía de Fluorescencia , Humanos , Fragmentos Fab de Inmunoglobulinas/inmunología , Conformación Molecular , Toxina T-2/análisis , Toxina T-2/inmunología

RESUMEN

The identification of chemicals that pose the greatest threat to human health from incidental releases is a cornerstone in public health preparedness for chemical threats. The present study developed and applied a methodology for the risk analysis and prioritization of industrial chemicals to identify the most significant chemicals that pose a threat to public health in Finland. The prioritization criteria included acute and chronic health hazards, physicochemical and environmental hazards, national production and use quantities, the physicochemical properties of the substances, and the history of substance-related incidents. The presented methodology enabled a systematic review and prioritization of industrial chemicals for the purpose of national public health preparedness for chemical incidents.

Asunto(s)

Industria Química , Exposición a Riesgos Ambientales/efectos adversos , Política Ambiental , Prioridades en Salud , Práctica de Salud Pública , Xenobióticos/toxicidad , Recolección de Datos , Monitoreo del Ambiente/métodos , Finlandia , Humanos , Sistema de Registros , Medición de Riesgo

RESUMEN

As a part of the project for screening unequivocal biomarkers after sulfur mustard exposure, a quantitative method for the determination of ß-lyase metabolites 1,1'-sulfonylbis-[2-(methylsulfinyl)ethane] (SBMSE) and 1-methylsulfinyl-2-[2-(methylthio)ethylsulfonyl]ethane (MSMTESE) was validated. Full validation was conducted according to the FDA guidelines for method validation using pooled human urine as a sample matrix. The metabolites were extracted from urine with an optimized sample preparation procedure using ENV+ solid phase extraction cartridge with reduced volume of sample and solvents. Metabolites were detected by improved and faster liquid chromatography-heated electrospray ionization-tandem mass spectrometry (LC-HESI-MS/MS) method with two transitions of each chemical using non-buffered eluents, post-column splitter and higher flow-rate. These provided over five times faster analysis than previously published method providing 4.5 min/sample cycle time, to achieve up to 200 samples per day (24 h). Quantification was performed using deuterium labelled internal standard of SBMSE. The method was linear over the concentration range of 5-200 ng/ml (average correlation coefficients were R(2)=0.997 and R(2)=0.989) for both ß-lyase metabolites, SBMSE and MSMTESE, respectively. The average retention times for SBMSE and MSMTESE were 1.96±0.01 min and 3.24±0.03 min (n=54). Calculated limits of detection were 4 ng/ml for both SBMSE and MSMTESE, respectively. Lower limits of quantification were 10 ng/ml and 11 ng/ml for SBMSE and MSMTESE, respectively. This validated method was successfully used in the First Confidence Building Exercise on Biomedical Samples Analysis organized by the Organisation for the Prohibition of Chemical Weapons (OPCW). Identification criteria for analysing unequivocal biomarkers of sulfur mustard with LC-MS/MS after alleged use is discussed and proposed based on the validation and exercise results.

Asunto(s)

Sustancias para la Guerra Química/farmacocinética , Marcaje Isotópico/métodos , Liasas/metabolismo , Gas Mostaza/farmacocinética , Espectrometría de Masa por Ionización de Electrospray/métodos , Sulfuros/orina , Sulfonas/orina , Sulfóxidos/orina , Análisis de Varianza , Biomarcadores/metabolismo , Biomarcadores/orina , Sustancias para la Guerra Química/análisis , Sustancias para la Guerra Química/envenenamiento , Humanos , Marcaje Isotópico/normas , Modelos Lineales , Gas Mostaza/análisis , Gas Mostaza/envenenamiento , Intoxicación/orina , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Extracción en Fase Sólida , Espectrometría de Masa por Ionización de Electrospray/normas , Sulfuros/metabolismo , Sulfonas/metabolismo , Sulfóxidos/metabolismo , Espectrometría de Masas en Tándem/métodos , Espectrometría de Masas en Tándem/normas

RESUMEN

A computational and experimental matrix isolation study of insertion of noble gas atoms into cyanoacetylene (HCCCN) is presented. Twelve novel noble gas insertion compounds are found to be kinetically stable at the MP2 level of theory, including four molecules with argon. The first group of the computationally studied molecules belongs to noble gas hydrides (HNgCCCN and HNgCCNC), and we found their stability for Ng = Ar, Kr, and Xe. The HNgCCCN compounds with Kr and Xe have similar stability to that of previously reported HKrCN and HXeCN. The HArCCCN molecule seems to have a weaker H-Ar bond than in the previously identified HArF molecule. The HNgCCNC molecules are less stable than the HNgCCCN isomers for all noble gas atoms. The second group of the computational insertion compounds, HCCNgCN and HCCNgNC, are of a different type, and they also are kinetically stable for Ng = Ar, Kr, and Xe. Our photolysis and annealing experiments with low-temperature cyanoacetylene/Ng (Ng = Ar, Kr, and Xe) matrixes evidence the formation of two noble gas hydrides for Ng = Kr and Xe, with the strongest IR absorption bands at 1492.1 and 1624.5 cm(-1), and two additional absorption modes for each species are found. The computational spectra of HKrCCCN and HXeCCCN fit most closely the experimental data, which is the basis for our assignment. The obtained species absorb at quite similar frequencies as the known HKrCN and HXeCN molecules, which is in agreement with the theoretical predictions. No strong candidates for an Ar compound are observed in the IR absorption spectra. As an important side product of this work, the data obtained in long-term decay of KrHKr+ cations suggest a tentative assignment for the CCCN radical.

RESUMEN

New organic rare-gas compounds, HRgC4H (Rg = Kr or Xe), are identified in matrix-isolation experiments supported by ab initio calculations. These compounds are the largest molecules among the known rare-gas hydrides. They are prepared in low-temperature rare-gas matrixes via UV photolysis of diacetylene and subsequent thermal mobilization of H atoms at approximately 30 and 45 K for Kr and Xe, respectively. The strongest IR absorption bands of the HRgC4H molecules are the H-Rg stretches with the most intense components at 1290 cm(-1) for HKrC4H and at 1532 cm(-1) for HXeC4H, and a number of weaker absorptions (C-H stretching, C-C-C bending, and C-C-H bending modes) are also found in agreement with the theoretical predictions. As probably the most important result, the IR absorption spectra indicate some further stabilization of the HRgC4H molecules as compared with the corresponding HRgC2H species identified recently (Khriachtchev et al. J. Am. Chem. Soc. 2003, 125, 4696 and Khriachtchev et al. J. Am. Chem. Soc. 2003, 125, 6876). The computational energetic results support this trend. HXeC4H is predicted to be 2.5 eV lower in energy than H + Xe + C4H, which is approximately 1 eV larger than the corresponding value for HXeC2H. We expect that the larger molecules HRgC6H and HRgC8H are even more stable and the HRgC2nH species are good candidates for bulk organic rare-gas material.

RESUMEN

An organic molecule containing krypton, HKrCCH, is reported. The preparation of HKrCCH includes 193-nm photolysis of H2C2/Kr solid mixtures at 8 K and subsequent thermal mobilization of hydrogen atoms at >/=30 K. The identification is based on infrared absorption spectroscopy and supported by ab initio calculations which show ionic and covalent contributions to the bonding. We believe that a series of similar organokrypton molecules can be prepared as computationally demonstrated for HKrC4H and HKrC3H3. These results feature a generally novel way for activating chemically the H-CC- group, which can find practical applications of the krypton catalysis.

RESUMEN

Three novel Xe-containing organic compounds, HXeCCH, HXeCC (open-shell species), and HXeCCXeH, are identified using infrared absorption spectroscopy. They are prepared in a low-temperature Xe matrix using UV photolysis of acetylene and subsequent annealing at 40-45 K. The experimental observations are supported by extensive ab initio calculations. This work demonstrates a new way to activate the H-Ctbd1;C- group without use of XeF(2), which can extend the range of organoxenon compounds.