Gas-chromatographic determination of O-isobutyl-S-2-(N,N-diethylamino)ethyl methylphosphonothioate (VX-like compound) and O-isopropyl methylphosphonofluoridate (Sarin) traces in slag

Procedures for the determination of 04sobutyl- S-2-(N,N-diethylamino)ethyl methylphosphonothioate (VX-like compound) and sarin traces in slag at levels of 5 × 10^-5 and 1 × 10^-2 mg/kg, respectively, were developed. The procedures are based on the extraction of organophosphorus chemical warfare agents from slag, the preconcentration of the extract, and the conversion of the analytes into dialkyl methylphos-phonates with the use of optically active alcohols. In this case, a solution of AgNO₃ in 4-methyl-2-pentanol or a sodium alcoholate solution was used for the derivatization of VX or sarin, respectively. The resulting dias-tereomers were determined by gas chromatography with the use of a flame-photometric detector. The analysis time was no longer than 1.2 or 1 h for the VX-like compound or sarin, respectively.     

Gas-Chromatographic Determination of Trace Isobutyl S-2-(N,N-Diethylamino)ethyl Methylphosphonothioate (VX-like Compound) in Soil and Construction Materials

Procedures were developed for the determination of trace isobutyl S-2-(N,N-diethylamino)ethyl methylphosphonothioate (IBDAEMP) in soil and construction materials by gas chromatography at a level of 1 × 10^–9%. The procedures are based on the extraction of IBDAEMP from test materials using an aqueous solution of monoethanolamine or chloroform saturated with ammonia, the back extraction of IBDAEMP into hexane, the evaporation of the hexane solution (with an addition of HCl) to dryness, the treatment of the residue with a solution of silver nitrate in methanol for obtaining O-isobutyl O-methyl methylphosphonate, and gas-chromatographic separation on an open tubular column with the HP–5MS chemically modified stationary phase with flame-photometric detection.     

Influence of interparticle interactions on the kinetics of self-assembly and mechanical strength of nanoparticulate aggregates

Computer simulations based on Discrete Element Method have been performed in order to investigate the influence of interparticle interactions on the kinetics of self-assembly and the mechanical strength of nanoparticle aggregates.Three different systems have been considered.In the first system the interaction between particles has been simulated using the JKR (Johnson,Kendall and Roberts) contact theory,while in the second and third systems the interaction between particles has been simulated using van der Waals and electrostatic forces respectively.In order to compare the mechanical behaviour of the three systems,the magnitude of the maximum attractive force between particles has been kept the same in all cases.However,the relationship between force and separation distance differs from case to case and thus,the range of the interparticle force.The results clearly indicate that as the range of the interparticle force increases,the self-assembly process is faster and the work required to produce the mechanical failure of the assemblies increases by more than one order of magnitude.     

Determination of residual amounts ofO-IsobutylS-2-(N,N-Diethylamino)ethyl methylphosphonate in decontaminating solutions by gas chromatography

A method is proposed for the determination ofO-isobutylS-2-(N,N-diethylamino)ethyl methylphosphonate (mixed ester, ME) in spent decontaminating solutions by gas chromatography at a level of 1 x 10^-5%. The interfering effect of mono- and diisobutyl methylphosphonates (matrix components formed on the destruction of ME) is eliminated by extraction and back extraction. The effect of bis(N,N-diethylaminoethyl) disulfide in the determination of ME is eliminated by changing the order of elution from a Chromatographic column. Decontaminating solutions that are used in the laboratory practice for the detoxication of hydrophilic process ME solutions are aqueous solutions of alkali hydroxide with additions of hydrogen peroxide and an emulsifier.     

Gas-Chromatographic Determination of Sarin, Soman, and O-Isobutyl S-2-(N,N-Diethylamino)ethyl Methylphosphonothioate (a VX-Like Compound) Traces in Water

A gas-chromatographic procedure for the determination of O-isobutyl S-2-(N,N-diethylamino)ethyl methylphosphonothioate (VX), sarin, and soman in water at levels of 2 × 10^–6, 5 × 10^–5, and 2 × 10^–6 mg/L, respectively, was proposed. The procedure includes liquid–liquid extraction with the use of salting-out agents, back extraction, and evaporation. In this case, the VX compound was converted into O-isobutyl O-methyl methylphosphonate (a substance convenient for chromatographic determination) by the reaction with hydrochloric acid, methanol, thriethylamine, and silver nitrate.     

Gas-chromatographic determination of trace sarin and soman in atmospheric air of work zones and inhabited areas

A procedure was developed for the gas-chromatographic determination of sarin and soman in the atmospheric air of work zones and inhabited areas at a level of the maximum permissible concentration 2 × 10^?5 and 1 × 10^?5 mg/m³ and the tentative safe exposure level 2 × 10^?7 and 1 × 10^?7 mg/m³, respectively. The procedure is based on the recovery of sarin and soman from analyzed air using an absorbing solution, the extraction of sarin and soman from this solution with ethyl acetate and hexane, respectively, the evaporation of the corresponding extracts to a residual volume of 0.1 cm³, and their subsequent chromatography with flame-photometric and thermoionic detectors. The relative error in the determination of sarin and soman is 20 and 18 rel %, respectively, in the air of work zones and 27 and 23 rel %, respectively, in the air of inhabited areas.     

Gas Chromatographic Determination of Sulfur Mustard and Lewisite in Community Air

A gas chromatographic procedure is developed for the determination of ,-dichlorodiethylsulfide (yperite, sulfur mustard) and -chlorovinyldichloroarsine (lewisite) in the working area and community air at a level defined by the hygienic regulations for community air (2 × 10^–6 and 4 × 10^–6 mg/m³ for sulfur mustard and lewisite, respectively) and at the maximum permissible level for a working area (2 × 10^–4 mg/m³). The procedure for the determination of sulfur mustard is based on the trapping of the analyte from air with Silochrom S-120 impregnated with Apiezon L with further extraction by a 1 : 1 acetone–hexane mixture, the evaporation of the extract to a small residual volume, and chromatography with an electron capture detector. The procedure for the determination of -chlorovinyldichloroarsine (lewisite) involves the absorption of the analyte with a 2.2% solution of triethanolamine in 0.1 M hydrochloric acid, the conversion of lewisite to acetylene by treating the trap contents with 30% alkali solution, and the chromatography of the vapor phase using a flame ionization detector. The error of the determination is no more than ±23 rel %. The analysis takes 1.5 h.     

Gas-chromatographic determination of trace amounts of tetrodotoxin in water,drugs, and blood plasma

A method has been developed for the determination of tetrodotoxin in water, blood plasma, and drugs at a level of 0.05—1.0 µg/mL. The method is based on the hydrolytic decomposition of tetrodotoxin by a sodium hydroxide solution, extraction of 2-amino-6-hydroxymethyl-8-hydroxyquinazoline using liquid–liquid extraction, preparation of its derivative by reaction with N,O-bis(trimethylsilyl)trifluroacetamide, and the determination of the derivative by gas–liquid chromatography with a mass-spectrometric detector.