Effects of Nitrobenzenes on DNA Damage in Germ Cells of Rats

IntroductionSince nitroaromatic compounds constitute a classof industrial chemicals that are present in China andprobably in many other industrialized countries as well,it is necessary to gain insight into their potential hazardto organisms.In recent year…     

活性炭纤维固相微萃取-气相色谱法测定海水中的硝基苯类和环酮类化合物

建立了自制活性炭纤维固相微萃取与气相色谱联用测定海水中6种硝基苯类和环酮类化合物的分析方法。优化的萃取条件为: 样品中加NaCl至饱和,在1500 r/min速率搅拌下,于60 ℃水浴中顶空萃取30 min,于280 ℃下解吸2 min。方法的线性范围为0.01～400 μg/L,检出限为1.4～3.2 ng/L,相对标准偏差(RSD,n6)为1.4%～7.8%。海水样品中硝基苯类和环酮类化合物的加标回收率和RSD分别为86.3%～101.8%和3.7%～7.8%。应用所建立的方法对东海近岸表层水样进行测定,其中硝基苯、1,3-二硝基苯、2,6-二硝基甲苯的质量浓度分别为0.756,0.944,0.890 μg/L。实验结果表明,该方法简便、高效、无需有机溶剂,适合于海洋水体中硝基苯类和环酮类化合物的分析。     

Metabolism of 2,4-dinitrotoluene and 2,6-dinitrotoluene, and their dinitrobenzyl alcohols and dinitrobenzaldehydes by Wistar and Sprague-Dawley rat liver microsomal and cytosol fractions

The metabolism of 2,4-dinitrotoluene (2,4-DNT), 2,4-dinitrobenzyl alcohol (2,4-DNB), 2,4-dinitrobenzaldehyde (2,4-DNBAl), 2,6-DNT, 2,6-DNB and 2,6-DNBAl in the microsomal and cytosol fractions prepared from unfortified male Wistar and male Sprague-Dawley (S.D.) rat livers was investigated. Data obtained by high-performance liquid chromatography (HPLC) indicated that the products of dinitrotoluenes (2,4-DNT and 2,6-DNT), dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB), and dinitrobenzaldehydes (2,4-DNBAl and 2,6-DNBAl) in the microsomal and cytosol preparations containing nicotinamide adenine dinucleotide phosphate (NAD(P] and reduced NAD(P)(NAD(P)H) were dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB), dinitrobenzaldehydes (2,4-DNBAl and 2,6-DNBAl), and dinitrobenzoic acids (2,4-DNBA and 2,6-DNBA), and dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB), respectively. From these results, it was concluded that the dinitrobenzaldehydes (2,4-DNBAl and 2,6-DNBAl) were intermediates in the oxidations of dinitrobenzyl alchols (2,4-DNB and 2,6-DNB) to dinitrobenzoic acids (2,4-DNBA and 2,6-DNBA), and that the oxidations of dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB) to dinitrobenzaldehydes (2,4-DNBAl and 2,6-DNBAl) and the reductions of dinitrobenzaldehydes to dinitrobenzyl alcohols (2,4-DNB and 2,6-DNB) were reversible.(ABSTRACT TRUNCATED AT 250 WORDS)     

The determination of nitroaromatics and nitramines in ground and drinking water by wide-bore capillary gas chromatography

A method has been developed to determine the concentration of nitroaromatics and nitramines in drinking water at levels below those previously achieved by gas chromatography. The nitroaromatics and nitramines are extracted from water using toluene and isoamyl acetate, respectively. The extracts are analyzed via a gas chromatograph equipped with a DB-1301 widebore fused-silica capillary column and an electron capture detector. Method detection limits of 0.003 micrograms/L for 2,6-dinitrotoluene (2,6-DNT), 0.04 micrograms/L for 2,4-dinitrotoluene (2,4-DNT), 0.06 micrograms/L for 2,4,6-trinitrotoluene (TNT), 0.3 micrograms/L for cyclotrimethylenetrinitramine (RDX), and 6.0 micrograms/L for cyclotetramethylenetetranitramine (HMX) have been obtained using this method.     

Simultaneous Determination of Hydroquinone and Catechol by Differential Alternative Pulses Voltammetry

The second order voltammetric technique of high resolution, Differential Alternative Pulses Voltammetry (DAPV), was applied for the simultaneous determination of hydroquinone (HQ) and catechol (CC) on bare spectroscopic graphite electrode. Well resolved anodic and cathodic peaks situated on both sides of the zero line were obtained, while the differential pulse voltammograms were overlapped. The linear concentration range for HQ and CC quantification by DAPV was extended up to 20 μmol L⁻¹ for both the isomers. The sensitivity of the determination was found to be 6.00 μA L μmol⁻¹ and 3.61 μA L μmol⁻¹, while the limit of detection reached was 0.2 μmol L⁻¹ and 0.5 μmol L⁻¹ for HQ and CC, respectively. No interference was observed from the commonly coexisting organic species such as resorcinol, phenol and p‐benzoquinone. The great resolution power of DAPV permitted obtaining excellent results without any electrode modification and any mathematical data processing.     

超声-气相联合扩散法快速合成ZIF-8用于硝基芳香化合物炸药的传感

三维微孔沸石咪唑基骨架(ZIF-8)纳米晶通过超声-气相联合扩散法快速合成.对该纳米晶进行荧光研究表明,纳米晶对硝基芳香化合物炸药具有良好的荧光淬灭能力.通过建立的Stern-Volmer方程,在1×10-4～8×10-4 mol/L范围内,每种炸药的浓度与纳米晶的荧光淬灭程度呈线性关系.对于2,4,6-三硝基苯酚(T...     

Development of a sensitive surface plasmon resonance immunosensor for detection of 2,4-dinitrotoluene with a novel oligo (ethylene glycol)-based sensor surface

A surface plasmon resonance (SPR) immunosensor for detection of 2,4-dinitrotoluene (2,4-DNT), which is a signature compound of 2,4,6-trinitrotoluene-related explosives, was developed by using a novel oligo (ethylene glycol) (OEG)-based sensor surface. A rabbit polyclonal antibody against 2,4-DNT (anti-DNPh-KLH-400 antibody) was prepared, and the avidity for 2,4-DNT and recognition capability were investigated by indirect competitive ELISA. The sensor surface was fabricated by immobilizing a 2,4-DNT analog onto an OEG-based self-assembled monolayer formed on a gold surface via an OEG linker. The fabricated surface was characterized by Fourier-transform infrared-refractive absorption spectrometry (FTIR-RAS). The immunosensing of 2,4-DNT is based on the indirect competitive principle, in which the immunoreaction between the anti-DNPh-KLH-400 antibody and 2,4-DNT on the sensor surface was inhibited in the presence of free 2,4-DNT in solution. The limit of detection for the immunosensor, calculated as three times the standard deviation of a blank value, was 20 pg mL⁻¹, and the linear dynamic range was found to be between 1 and 100 ng mL⁻¹. Additionally, the fabricated OEG-based surface effectively prevented non-specific adsorption of proteins, and the specific response to anti-DNPh-KLH-400 antibody was maintained for more than 30 measurement cycles.     

Solvating gas chromatography with chemiluminescence detection of nitroglycerine and other explosives

A separation technique known as solvating gas chromatography (SGC), which utilizes packed capillary columns and neat carbon dioxide as mobile phase, was used for the separation of nitroglycerine (NG) and other nitrogen-containing explosives including 2,6-dinitrotoluene (2,6-DNT), 2,4-dinitrotolulene (2,4-DNT), 2,4,6-trinitrotoluene (2,4,6-TNT), and pentaerythritol tetranitrate (PETN). SGC was coupled for the first time to a selective chemiluminescence thermal energy analyzer (TEA) detector for nitro-functional group specificity and sensitive detection of these compounds. TEA calibration curve for NG showed linearity in the sub-microg ml(-1) range. Soil samples containing NG were used to test the validity of the technique. Detector response of SGC-TEA versus SGC-flame ionization detection for NG was also evaluated.     

Atmospheric pressure chemical ionization negative mass spectra of the dinitrotoluene isomers

The atmospheric pressure chemical ionization of the dinitrotoluene isomers in ambient air was studied with a quadrupole mass spectrometer operating in the negative mode. The isomers can be grouped on the basis of the product ions: 2,5-, and 2,6- and 3,5-dinitrotoluene give the molecular anion with little fragmentation; 2,3- and the 3,4-dinitrotoluene behave similarly but with more extensive fragmentation; 2,4-dinitrotoluene gives the quasimolecular [DNT ? H]^? ion with little fragmentation. The results are discussed in terms of the molecular structure of the isomers.     

Determination of nitroaromatic, nitramine, and nitrate ester explosives in soil by gas chromatography and an electron capture detector

Hazardous waste site characterization, forensic investigations, and land mine detection are scenarios where soils may be collected and analyzed for traces of nitroaromatic, nitramine, and nitrate ester explosives. These thermally labile analytes are traditionally determined by high-performance liquid chromatography (HPLC); however, commercially available deactivated injection port liners and wide-bore capillary columns have made routine analysis by gas chromatography (GC) possible. The electron-withdrawing nitro group common to each of these explosives makes the electron capture detector (ECD) suitable for determination of low concentrations of explosives in soil, water, and air. GC-ECD and HPLC-UV concentration estimates of explosives residues in field-contaminated soils from hazardous waste sites were compared, and correlation (r>0.97) was excellent between the two methods of analysis for each of the compounds most frequently detected: 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4-dinitrotoluene (2,4-DNT), 1,3-dinitrobenzene (1,3-DNB), 1,3,5-trinitrobenzene (TNB), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). The analytes were extracted from soils with acetonitrile by 18 h of sonication in a cooled ultrasonic bath. Two soil-to-solvent ratios were evaluated: 2.00 g:10.00 ml and 25.0 g:50.0 ml. GC-ECD method detection limits were similar for the two soil-to-solvent ratios and were about 1 mug kg(-1) for the di- and trinitroaromatics, about 10 mug kg(-1) for the mono-nitroaromatics, 3 mug kg(-1) for RDX, 25 mug kg(-1) for HMX, and between 10 and 40 mug kg(-1) for the nitrate esters (nitroglycerine [NG] and pentaerythritol tetranitrate [PETN]). Spike recovery studies revealed artifacts introduced by the spiking procedure. Recoveries were low in some soils if the amount of soil spiked was large (25.0 g) compared to the volume of spike solution added (1.00 ml). Recoveries were close to 100% when 2.00-g soil samples were spiked with 1.00 ml of solution. Analytes most frequently found in soils collected near buried land mines were the microbial transformation products of TNT (2-amino-4,6-dinitrotoluene [2-Am-DNT] and 4-amino-2,6-dinitrotoluene [4-Am-DNT]), manufacturing impurities of TNT (2,4-DNT, 2,6-DNT, and 1,3-DNB), and TNT. The microbial reduction products of the isomers of DNT and of 1,3-DNB were also detected, but the ECD response to these compounds is poor.     

2,4-二硝基甲苯热解自催化特性鉴别及其热解动力学

为研究2,4-二硝基甲苯(2,4-DNT)的热危险性及其分解反应的特征, 利用差示扫描量热仪(DSC)对该物质进行了动态扫描测试, 得到其起始分解温度T₀范围为272.4-303.5℃, 分解热ΔH_d约为2.22 kJ·g^-1. 在此基础上, 采用瑞士安全技术与保障研究所提出的快速鉴别法(瑞士方法)及数值模拟技术, 对其分解反应的特性参数进行了推算, 结果表明其分解具有自催化性. 采用Malek法分析了该物质分解反应的最概然机理函数并得出了相关动力学参数, 表明其分解具有自催化性且符合Sestak-Berggren 双参数自催化模型(SB模型), 这与瑞士方法所得结论一致. 采用等温DSC测试获得了该物质的‘钟形’热解曲线, 从而验证了两种方法的结论.     

Sorption of nitroaromatic compounds to synthesized organoclays

This project quantifies the ability of seven engineered organoclays to sorb TNT and two of its reduction products: 2-amino-4,6-dinitrotoluene (2-A-4,6-DNT) and 4-amino-2,6-dinitrotoluene (4-A-2,6-DNT). The organoclays used in the TNT sorption studies were synthesized in the laboratory by combining bentonite with benzyltriethylammonium chloride (BTEA) at 50, 75, and 100% of the bentonite's cation exchange capacity and with hexadecyltrimethylammonium bromide (HDTMA) at 25, 50, 75, and 100% of the bentonite's cation exchange capacity. For sorption of 2-A-4,6-DNT and 4-A-2,6-DNT, two organoclays were tested: BTEA at 50% CEC and HDTMA at 75% CEC. Sorption data with HDTMA organoclay and TNT were fit to linear isotherms and demonstrated that the clay's sorptive capacity increased as the amount of total organic carbon exchanged onto the clay increased. Sorption data with BTEA organoclay and TNT were fit to Langmuir isotherms; however, the clay's sorptive capacity increased as the amount of total organic carbon sorbed to the clay's surface was decreased. Sorption behavior for TNT reduction products 2-A-4,6-DNT and 4-A-2,6-DNT to one HDTMA organoclay and one BTEA organoclay demonstrated that HDTMA organoclay at 10.3% total organic carbon was a more effective sorbent than BTEA organoclay at 5.2% total organic carbon.     

Studies of Solvent Effects on Structure and Low Frequency Vibrational Spectra of 2,4-Dinitrotoluene

Solvent effects on 2,4-dinitrotoluene(2,4-DNT) molecule in different solvents(toluene,ethanol,and water) were studied via DFT PCM method at B3LYP/6-311+G(d,p) level. The influences of these solvents on the molecular structure,vibrational spectra,charge distribution,and dipole moment were studied as well. The results show that PCM computations are successful in describing the vibrational spectra of 2,4-DNT molecules in these solutions and the solvent effects on the low frequency vibrational spectra are weak.     

Tellurium Film Electrodes Deposited on Carbon and Mesoporous Carbon Screen‐printed Substrates for Anodic Stripping Voltammetric Determination of Copper

The performance of screen‐printed electrodes modified in situ with tellurium film for the anodic stripping voltammetric (ASV) determination of Cu(II) is reported. It was found that two types of screen‐printed substrates, namely carbon and mesoporous carbon, were optimal for this application. The selected in situ tellurium film modified electrodes were applied for the square wave ASV determination of copper at μg L⁻¹ concentration levels. Well‐defined and reproducible Cu oxidation stripping peaks were produced at a potential more negative than the anodic dissolution of tellurium. The highest sensitivity of Cu determination was achieved in 0.05 M HCl containing 50 μg L⁻¹ Te(IV) after 300 s of accumulation at −0.5 V. Using the optimized procedure, a linear range from 2 to 35 μg L⁻¹ of Cu(II) was obtained with a detection limit of 0.5 μg L⁻¹ Cu(II) (S/N=3) for 300 s of deposition time. Both sensors, carbon TeF‐SPE and mesoporous carbon TeF‐SPE, were successfully applied for the quantification of Cu in a certified reference surface water sample.     

Metabolic studies of explosives. 5. Detection and analysis of 2,4,6-trinitrotoluene and its metabolites in urine of munition workers by micro liquid chromatography/mass spectrometry

Metabolites of 2,4,6-trinitrotoluene (TNT) were found in the urine of a group of TNT munition workers. The urine extracts were analysed by micro liquid chromatography/mass spectrometry. The metabolites found included 2-amino-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene, 2,4-diamino-6-nitrotoluene, 2,6-diamino-4-nitrotoluene and untransformed TNT. The detection limit of the metabolites in urine was 0.1 ng/ml for 20 ml urine samples.     

Resolution of a Mononitrophenol Isomers Mixture by Differential Alternative Pulses Voltammetry

The high resolution second order voltammetric technique, Differential Alternative Pulse Voltammetry (DAPV), was applied for the simultaneous quantification of the mononitrophenol (NP) isomers. Complete resolution of the three isomers was achieved at concentration ratios as high as 1 : 5, employing the corresponding anodic and cathodic peaks appeared on the DAPV curve. The working glassy carbon electrode was modified by a nanocomposite of graphite nanopowder and Au nanoparticles to increase the sensitivity. The linear concentration range was found to be extended up to 125 μmol L^?1 for both the m‐NP and p‐NP isomers, while the o‐NP isomer presented calibration plot of two linear sections: up to 100 μmol L^?1 and up to 225 μmol L^?1. The LOD was found to be as low as 1.5 μmol L^?1, 2.5 μmol L^?1, and 0.5 μmol L^?1 for o‐NP, m‐NP, and p‐NP, respectively. The accuracy of the proposed method was evaluated by quantification of spiked tap waters samples. No interference was observed from a range of phenolic compounds such as phenol, 4‐aminophenol, 4‐chlorophenol, 2,4‐dinitrophenol, and resorcinol.     

Solid phase microextraction ion mobility spectrometer interface for explosive and taggant detection

Ion mobility spectrometry (IMS) is a rugged, inexpensive, sensitive, field portable technique for the detection of organic compounds. It is widely employed in ports of entry and by the military as a particle detector for explosives and drugs of abuse. Solid phase microextraction (SPME) is an effective extraction technique that has been successfully employed in the field for the pre-concentration of a variety of compounds. Many organic high explosives do not have a high enough vapor pressure for effective vapor sampling. However, these explosives and their commercial explosive mixtures have characteristic volatile components detectable in their headspace. In addition, taggants are added to explosives to aid in detection through headspace sampling. SPME can easily extract these compounds from the headspace for IMS vapor detection. An interface that couples SPME to IMS was constructed and evaluated for the detection of the following detection taggants: 2-nitrotoluene (2-NT), 4-nitrotoluene (4-NT), and 2,3-dimethyl-2,3-dinitrobutane (DMNB). The interface was also evaluated for the following common explosives: smokeless powder (nitrocellulose, NC), 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), 2,4,6-trinitrotoluene (2,4,6-TNT), hexahydro-1,3,5-trinitro-s-triazine (RDX), and pentaerythritol tetranitrate (PETN). This is the first peer reviewed report of a SPME-IMS system that is shown to extract volatile constituent chemicals and detection taggants in explosives from a headspace for subsequent detection in a simple, rapid, sensitive, and inexpensive manner.     

Development of imprinted materials for the selective extraction of nitroaromatic explosives

Molecularly imprinted sorbents were synthesized and used as selective extraction sorbents for the analysis of nitroaromatic explosives. Their synthesis by radical polymerization using organic monomers and by sol–gel approach using organosilanes was considered to develop a selective sorbent. The sol–gel approach with phenyltrimethoxysilane (PTMS) as monomer and 2,4-dinitrotoluene (2,4-DNT) as template gave the most promising results. An optimized procedure adapted to the selective treatment of aqueous samples was then developed and applied to various target explosives. For the first time four nitroaromatic compounds were retained on the molecularly imprinted silica (MIS) with extraction recoveries between 29% and 81%, while only low recoveries were obtained on the non-imprinted sorbent, thus highlighting the high degree of selectivity. The MIS was then used for the clean-up of a sample containing motor oil spiked with 2,4-DNT and 2,4,6-trinitrotoluene (2,4,6-TNT). The results were compared with those obtained using a conventional sorbent (Oasis HLB). The cleanest chromatogram obtained using the MIS emphasized the high potential of the MIS as selective sorbent.     

Electrochemical sensing platform based on the use of ZnONPs and MWCNTs as CPE modifiers for a selective and sensitive determination of polyamine spermine in the urine sample

A simple electroanalytical procedure has been developed for the determination of polyamine spermine using the ZnONPs-MWCNTs-CPE sensor. Spermine has been irreversibly oxidized on a modified electrode at a potential of +0.92 V versus Ag/AgCl (KCl, 3.5 mol L⁻¹). The developed sensor demonstrated a respective linear response in borate buffer pH 8.5 from 2 μmol L⁻¹ to 100 μmol L⁻¹, with a detection limit of 0.300 μmol L⁻¹ and quantification limit of 0.998 μmol L⁻¹. The proposed sensor showed high reproducibility (RSD = 2.58 %), stability, robustness, and no obvious interference effects of several inorganic ions and organic molecules. The obtained results demonstrated excellent performance during the determination of the spermine in human urine samples with satisfactory recovery results (98.41–101.34 %), offering promising opportunities for practical clinical analysis.     

A new Approach for the Voltammetric Sensing of the Phytoestrogen Genistein at a Non-modified Boron-doped Diamond Electrode

An effective electrochemical sensor was constructed using an unmodified boron-doped diamond electrode for determination of genistein by square-wave voltammetry. Cyclic voltammetric investigations of genistein with HClO₄ solution indicated that irreversible behavior, adsorption-controlled and well-defined two oxidation peaks at about +0.92 (P_A1) & +1.27 V (P_A2). pH, as well as supporting electrolytes, are important in genistein oxidations. Quantification analyses of genistein were conducted using its two oxidation peaks. Using optimized experiments as well as instrumental conditions, the current response with genistein was proportionately linear in the concentrations range of 0.1 to 50.0 μg mL⁻¹ (3.7×10⁻⁷−1.9×10⁻⁴ mol L⁻¹), by the detection limit of 0.023 μg mL⁻¹ (8.5×10⁻⁸ mol L⁻¹) for P_A1 and 0.028 μg mL⁻¹ (1.1×10⁻⁷ mol L⁻¹) for P_A2 in 0.1 mol L⁻¹ HClO₄ solution (in the open circuit condition at 30 s accumulation time). Ultimately, the developed method was effectively applied to detect genistein in model human urine samples by using its second oxidation peak (P_A2).