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Ricin is a type II ribosome-inactivating protein toxin consisting of A and B chains linked by one interchain disulfide bond. Because of its high toxicity depending on both chains together, confirming the presence of both A and B chains of intact ricin is required during the investigation of the illegal production and application. Here, we report a novel and sensitive acetonitrile (ACN)-assisted trypsin digestion method for unambiguous identification of intact ricin by simultaneous detection of its marker peptides from A and B chains. Marker peptides were generated with a simple procedure by direct cleaving the native ricin at 45 °C for 4 h using Promega modified sequencing grade trypsin under the assistance of 10% ACN, and then directly analyzed by ultrahigh performance liquid chromatography tandem mass spectrometry. The type of trypsin was found to be one critical factor for cleavage of intact ricin based on a significant difference in the yields of specific peptides generated while using various types of trypsin. A low content of ACN in enzymatic buffer significantly reduced the digestion time from overnight to 4 h. There was commonly a better MS response of marker peptides when using the developed ACN-assisted trypsin digestion method than methanol-assisted trypsin digestion within the same 4 h. Totally, seven specific peptides with high sensitivity and specificity including three in the A-chain (TA7, TA11, and TA10) and four in the B-chain (TB6, TB14-ss-TB16, TB20, and TB18) were obtained as good marker peptides for unambiguous identification of intact ricin. The lowest concentration of native ricin for unambiguous identification was 20 ng/mL, in which three marker peptides from both the A-chain and B-chain could be measured with a minimum of three ion transitions. Combined with affinity enrichment, the developed approach was successfully applied for the measurement of intact ricin from the complicated matrix samples of the second, third, and fourth biotoxin exercises organized by the Organisation for the Prohibition of Chemical Weapons (OPCW). This study has provided a recommended detection method combined with one novel ACN-assisted trypsin digestion with MS for forensic unambiguous confirmation of trace ricin intact with high confidence.

Four HD urinary metabolites including hydrolysis metabolite thiodiglycol (TDG), glutathione-derived metabolite 1,1'-sulfonylbis[2-S-(N-acetylcysteinyl)ethane] (SBSNAE), as well as the β-lyase metabolites 1,1'-sulfonylbis[2-(methylsulfinyl)ethane] (SBMSE) and 1-methylsulfinyl-2-[2-(methylthio) ethylsulfonyl]ethane (MSMTESE) are considered as important biomarkers for short-term retrospective detection of HD exposure. In this study, a single method for simultaneous quantification of the four HD metabolites in urine samples was developed using ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The four urinary metabolites were simultaneously extracted from urinary samples using a solid phase extraction (SPE) method with high extraction recoveries for all four metabolites varied in the range of 71.1-103% followed by UHPLC-MS/MS analysis. The SPE is simple and high effective only requiring 0.1mL of urinary samples and 0.5h time consuming. The problem of previous co-elution of TDG and SBSNAE in UHPLC was well solved, and complete separation of TDG, SBSNAE, SBMSE and MSMTESE from SPE-processed urine matrix was obtained to increase specificity and sensitivity. A full method validation was performed for each analyte in urine matrix. The linear range of calibration curves for the four analytes were respectively from 0.50-500ngmL-1 for TDG and SBSNAE, 0.05-500ngmL-1 for SBMSE and MSMTESE with coefficient of determination value (R2) ≥0.990. The limit of detection was 0.25ngmL-1 for TDG and SBSNAE, 0.01ngmL-1 for SBMSE and MSMTESE spiked in normal urine. The intra/inter-day precision for each analyte at three QC levels had relative standard deviation (%RSD) of ≤10.3%, and the intra/inter-day accuracy ranged between 88.0-108%. This developed method allows for simultaneous and trace measurement of four HD urinary metabolites within one single determination with the lowest usage amount of urine samples over all previous methods This study provides a useful tool for early diagnosis and monitoring of HD poisoning for medical treatment with high confidence, avoiding the need for application of several analysis methods.

This work describes a novel and sensitive non-isotope dilution method for simultaneous quantification of organophosphorus nerve agents (OPNAs) soman (GD) and VX adducts to butyrylcholinesterase (BChE), their aged methylphosphonic acid (MeP) adduct and unadducted BChE in plasma exposed to OPNA. OPNA-BChE adducts were isolated with an off-column procainamide-gel separation (PGS) from plasma, and then digested with pepsin into specific adducted FGES*AGAAS nonapeptide (NP) biomarkers. The resulting NPs were detected by UHPLC-MS/MS MRM. The off-column PGS method can capture over 90% of BChE, MeP-BChE, VX-BChE and GD-BChE from their respective plasma materials. One newly designed and easily synthesized phosphorylated BChE nonapeptide with one Gly-to-Ala mutation was successfully reported to serve as internal standard instead of traditional isotopically labeled BChE nonapeptide. The linear range of calibration curves were from 1.00-200ngmL-1 for VX-NP, 2.00-200ngmL-1 for GD-NP and MeP-NP (R2≥0.995), and 3.00-200ngmL-1 for BChE NP (R2≥0.990). The inter-day precision had relative standard deviation (%RSD) of

Uranium typically occurs in the hexavalent form U(Ⅵ) as the mobile, aqueous uranyl ion in radioactive wastewater. The reduction of soluble U(Ⅵ) to insoluble U(Ⅳ) oxide is an effective approach to eliminate uranium pollution. Herein, the metal organic framework material MIL-53(Fe) was successfully synthesized by a solvothermal method, and its application as photocatalyst in the reduction of U(Ⅵ) under visible light was studied in detail using various types and concentrations of hole trapping agents, solution pH values, and catalyst dosages. The results show that the use of formic acid as the hole trapping agent greatly accelerates the catalytic reaction rate by improving the charge separation efficiency. When 1 mmol·L

Sulfur mustard (HD) adduct to human serum albumin (ALB) at Cys-34 residue has become an important and long-term retrospective biomarker of HD exposure. Here, a novel, sensitive, and convenient approach for retrospective quantification of HD concentration exposed to plasma was established by detection of the HD-ALB adduct using ultra-high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with a novel non-isotope internal standard (IS). The HD-ALB adduct was isolated from HD-exposed plasma with blue Sepharose. The adduct was digested with proteinase K to form sulfur-hydroxyethylthioethyl ([S-HETE])-Cys-Pro-Phe tripeptide biomarker. The tripeptide adduct could be directly analyzed by UHPLC-MS/MS without an additional solid phase extraction (SPE), which was considered as a critical procedure in previous methods. The easily available 2-chloroethyl ethylsulfide (2-CEES) as HD surrogate was first reported to be used as IS in place of traditional d8-HD for quantification of HD exposure. Furthermore, 2-CEES was also confirmed to be a good IS alternative for quantification of HD exposure by investigation of product ion spectra for their corresponding tripeptide adducts which exhibited identical MS/MS fragmentation behaviors. The method was found to be linear between 1.00 and 250 ng•mL(-1) HD exposure (R(2)>0.9989) with precision of

Degradation of paraoxon and thioanisole (PhSMe) were studied using NH3modified H2O2solution as decontaminant. Degradation rates of paraoxon depend exponentially on pH of the modified solution. Nucleophilic substitution mediated by HOO-is the major degradation mechanism and at least two orders of magnitude faster than hydrolysis. Proton catalytic oxidation and solvent-aided oxidation contribute differently to the primary oxidation of PhSMe (PhSMe→PhS(O)Me), and the apparent kinetic constants (kap) of the primary oxidation show a three-stage profile with pH of the NH3-modified H2O2solution. Secondary oxidation of PhSMe (PhS(O) Me→PhS(O)2Me) is much slower than the primary oxidation in the modified H2O2solution, and the yield of PhS(O)2Me depended exponentially on pH too. The best pH range for the NH3modified H2O2solution as a broad-spectrum decontaminant is at 9.5-10.0 since a balance of nucleophilic/oxidizing decontamination reactivity could be achieved.

H2O2 aerosol was used to oxidize dichlorvos vapor. 80.7% of dichlorvos, with the initial concentration of 90.9 mg/m3, was decontaminated when the H2O2 concentration kept in the range of 110~130 mg/m3 within 60 min. According to the oxidation products, analyzed by GC-MS, the decontamination reaction mechanism was discussed. Radical chain reaction is the main decontamination mechanism. H2O2 is dissociated to HOO-, which can induce the formation of ·OH. The double bond in dichlorvos molecule is attacked by ·OH to form molecule radical, which is further oxidized to 1,1-dichloro ethoxy dimethyl phosphate, 1,1,1-trichloro-2-hydroxyl-ethyl dimethyl phosphate, dimethyl phosphite, dimethyl phosphate, trimethyl phosphate, methyl phosphate, dichloro acetaldehyde, oxalic acid, CH2Cl2, CHCl3, parts of which are mineralized to phosphoric acid, CO2, H2O and chloridion.

The present study was designed to develop a sensitive and selective high performance liquid chromatography–tandem mass spectrometric method for the determination of Camellianin A in HepG2 cells. The extraction of Camellianin A was achieved using 15% trichloroacetic acid and then separated on a C 18 column interfaced with a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode. The mobile phase was consisted of methanol–water (0.1% formic acid) (55 : 45, V / V ). The total run time was 5.0 min. The method was linear in the concentration range of 0.25–250.0 ng·mL −1 . The lower limit of quantification was 0.25 ng·mL −1 . The intra- and inter-day relative standard deviations of entire concentration range were less than 9.3%. The proposed HPLC-MS/MS method was successfully applied to detect the intracellular concentration of Camellianin A in HepG2 cells.

Two new glycoluril derivatives, namely 6-phenyl-1,4-dioxo-2,2a,3,4,6,7-hexahydro-1H,5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate (1), and diethyl 6-(2,4-dichorophenyl)-1,4-dioxo-2,2a,3,4,6,7-hexahydro-1H,5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate (2) have been synthesized and structurally determined by X-ray diffraction analysis. Compound 1 is, monoclinic, space group C2/c, with a = 20.0784(7), b = 9.0316(3), c = 23.0980(8) A, β = 98.3930(10), V = 4143.7(2) A3, with Z = 8 for d calc = 1.338 Mg/m3. The analog 2 is, Triclinic, space group P-1, with a = 8.9353(18), b = 10.466(2), c = 14.679(3) A, β = 73.60(3), V = 1268.1(4) A3, with Z = 2 for d calc = 1.533 Mg/m3. X-ray analysis reveals that both glycoluril derivatives bearing two free syn-urea NH groups and two ureidyl C=O, assemble the same one-dimensional chains in the solid-state running parallel to the [110], [1–10] and [010] directions via N–H···O hydrogen bonds. Two new glycoluril derivatives, namely 6-phenyl-1,4-dioxo-2,2a,3,4,6,7-hexahydro-1H,5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate (1), and diethyl 6-(2,4-dichorophenyl)-1,4-dioxo-2,2a,3,4,6,7-hexahydro-1H,5H-2,3,4a,6,7a-pentaazacyclopenta[cd]indene-2a,7b-dicarboxylate (2), both bearing two free syn-urea NH groups and two ureidyl C=O, assemble the same one-dimensional chains in the solid-state running parallel to the [110], [1–10] and [010] directions via R 2 2 (8) N–H···O hydrogen bonds.

During non-equilibrium plasma (NEP) reactions, chemical bonds of pollutant compound are broken by energy generated in the reactor so that the pollutants are decontaminated. In this study, the energy conversion factor ( E f ) is defined as the ratio of the dissociation energy of chemical bonds destroyed in NEP reaction system to the energy inputted in plasma reactor. The energy conversion factor of chemical bonds ( E f,i ), S–H, C–Cl, C–S, C–H, C–C etc., were determined by decontamination experiments of H 2 S and 2-CEES in plasma reactor. Based on the E f,i s, the predictive model of NEP decontamination efficiency of gaseous pollutant was developed and applied to predict decontamination efficiency of CH 3 CH 2 SH, in which all E f,i s of chemical bonds are known as described above. It was shown by the decontamination experiment of CH 3 CH 2 SH that the predictive value was well agreed to experimental data. Therefore, the model can be used to predict decontamination efficiency of those pollutants in which all E f,i s of chemical bonds have been determined. An improved model is also produced by the analysis of predictive error.

Decontamination of the VX surrogate (malathion) by the atmospheric pressure radio-frequency plasma jet (APPJ) was investigated. Optical emission spectroscopy was used to identify the active species and measure the neutral gas temperature. The effects of RF input power and exposing time on the decontamination efficiency and neutral gas temperature were investigated. The thermal effect and volatilization could be ignored from the APPJ decontamination mechanism in our processing conditions. The degradation products were identified by gas chromatograph coupled with mass spectrometers (GC–MS). Besides the trace amount of the oxidation product (malaxon), the main degradation products were formed by breaking the S–C bond of malathion. In the end, the main degradation mechanism was drawn out.

With the boosting demand for eco-friendly decontaminants, great achievements in peroxide-based decontaminating technologies have been made in recent years. These technologies have been applied in countering chemical/biological terrorist attacks, dealing with chemical/biological disasters and destructing environmental pollutants. Recent research advances in alpha-nucleophilic/oxidative reaction mechanisms of peroxide-based decontamination against chemical warfare agents were reviewed, and some classical peroxide-based decontaminants such as aqueous decontaminating solution, decontaminating foam, decontaminating emulsions, decontaminating gels, decontaminating vapors, and some newly developed decontaminating media (e.g., peroxide-based self-decontaminating materials and heterogeneous nano-catalytic decontamination systems) were introduced. However, currently available peroxide-based decontaminants still have some deficiencies. For example, their decontamination efficiencies are not as high as those of chlorine-containing decontaminants, and some peroxide-based decontaminants show relatively poor effect against certain agents. More study on the mechanisms of peroxide-based decontaminants and the interfacial interactions in heterogeneous decontamination media is suggested. New catalysts, multifunctional surfactants, self-decontaminating materials and corrosion preventing technologies should be developed before peroxide-based decontaminants really become true "green" decontaminants.

Disinfection with photocatalysis, compared to with the conventional cleanout, is both high efficient and non contaminative, but the simple TiO2 photocatalyst is showing to be of low activity and low active stability so to be hardly practical application. In the paper, SO4(2-)/TiO2 were papered by surface modification of TiO2 with dilute H2SO4, and the photocatalytic degradation of 2-chloroethyl ethyl sulfide (2-CEES) on the samples was examined in a fixed-bed microreactor. The examination show that the acidic modification enhanced both the activity and the active stability of TiO2, and the sample ST200 prepared by calcination at 200 degrees C was better than ST400 by calcination at 400 degrees C. The effect of water vapor content and reaction temperature on the photocatalytic degradation of 2-CEES was also tested, showing that the sample ST200 had high activity and stability at 90 degrees C, and kept a constant activity when adding 30.5 mL/L water vapor into the reactive system in which 2-CEES initial concentration was low to61 microL x L(-1). In addition, it was found that supporting SO4(2-)/TiO2 on gamma-Al2O3, SiO2 and active carbon could improve on the activity and stability of SO4(2-)/TiO2, and on supports SiO2 is the best one.

The mol­ecule of the title compound, C11H19N5O4, contains three fused rings, namely two nearly planar imidazole rings and one non-planar triazine ring. The latter ring displays a chair conformation. Two hydroxy­lmethyl­ene groups are linked to two N atoms from separate rings of the glycoluril system.

The title compound, C15H12F3N5O3, is a by-product isolated from the preparation of di-2-pyridiylglycoluril. The mol­ecule contains two classical intra­molecular N—H⋯N and N—H⋯O hydrogen bonds, and its crystal structure is stabilized mostly by inter­molecular N—H⋯O hydrogen bonds.

In the structure of the title compound, C33H26N2O4, two phthalimide units are symmetrically linked by a bis­(3,5-dimethyl­phen­yl)methane bridge. The methyl­ene C atom of this bridge lies on a twofold rotation axis. The dihedral angle between the planes of the two central benzene rings is 61.4 (4)°. The terminal isoindole group is approximately planar, with an r.m.s. deviation of atoms from the mean plane of 0.012 A and a dihedral angle of 75.3 (14)° with the attached benzene ring. An extensive network of C—H⋯O hydrogen bonds stabilizes the crystal structure.

The title compound, C14H18N4O8, is a glycoluril derivative, composed of two five-membered rings in envelope conformations and two six-membered rings in chair conformations. In the crystal structure, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network. One methyl group and the H atoms on the adjacent C atom are disordered over two positions; the site-occupancy factors are ca 0.62 and 0.38.