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。     

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...     

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…     

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)     

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.     

Investigation of different alcoholic modifiers for the separation and determination of two isomers of dinitrotoluene (2,4 and 2,6) by ion mobility spectrometry

Some alcoholic modifier gases were applied to separate isomer peaks in ion mobility spectrometry (IMS). Different mechanisms have been investigated on the separation, such as collision cross-section and analyte-modifier cluster formation. In this regard, some parameters that affected the cluster formation, such as dipole moment, electron affinity, the position of functional groups, and the modifier structure, were evaluated. On the other hand, some effective experimental parameters, including cell temperature and the flow rates of the drift and modifier gases, were also optimized. The combination of dispersive liquid–liquid microextraction with thin-film evaporation (DLLME-TFE) was used as a sample preparation method for the extraction of 2,4-dinitrotoluene (2,4-DNT) and 2,6-dinitrotoluene (2,6-DNT) isomers (as the target analytes). Isobutanol was selected as the alcoholic modifier to separate the ion molecular peaks of these isomers. The limit of detection and the limit of quantification obtained were 15 and 50 μg L⁻¹, and the linear dynamic range (50–700 μg L⁻¹) with coefficient of determination of 0.9941 and 0.9914 were obtained for 2,4-DNT and 2,6-DNT, respectively. The intra- and inter-day relative standard deviations were obtained between 3% and 5%. For validation of the method, determination of the isomers was accomplished for a red wastewater field sample, resulting in relative recovery values of about 96%.     

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.     

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.     

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.     

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.     

一种新的分离三硝基甲苯及其代谢产物的高效液相色谱方法

An HPLC method is described for separation of TNT and its main reduction metabolites. Two columns(LC-C(18) and LC-CN)are connected in series and operated isocratically at 1.0mL/min with water-methanol-tetrahydrofuran(60+ 35+ 5 ). The baseline separation of 4-amino-2,6-dinitrotoluene(4A) and 2-amino-4,6-dinitrotoluene(2A) ,which are main metabolites of TNT,is obtained(Rs=2.1).     

分散液-液微萃取与气相色谱-质谱联用分析环境水样中痕量的2,4-二硝基甲苯和磷酸三(2-氯乙基)酯

建立了分散液-液微萃取与气相色谱-质谱联用同时测定环境水样中痕量2,4-二硝基甲苯和磷酸三(2-氯乙基)酯的新方法。对影响萃取效率的因素进行了详细的考察和优化,确定采用的最佳萃取条件为: 将0.8 mL乙醇和60 μL氯仿的混合溶液快速注入5.0 mL的样品溶液中,振动混匀120 s后,离心分离,吸取沉积在试管底部的氯仿相直接进样分析。该方法对磷酸三(2-氯乙基)酯和2,4-二硝基甲苯的检出限(信噪比为3)分别为0.01和0.04 μg/L,富集倍数分别为96.6和127.5;两种物质的线性范围达3到4个数量级;日内和日间测定的相对标准偏差(RSDs, n=6)分别为8.6%～11.5%和8.9%～12.0%。将该方法用于环境水样中2,4-二硝基甲苯和磷酸三(2-氯乙基)酯的分析,其加标回收率为102.1%～110.9%。方法具有操作简单、方便快速、灵敏度高、无交叉污染和环境友好等优点。     

Simultaneous determination of organic and cationic species in explosives residues with column-switching liquid chromatography-ion chromatography system

A new column-switching method has been proposed for the determination of 14 organic explosives (1,3,5,7-tetranitro-N-methylaniline, 1,3,5-trinitro-1,3,5-triazacyclohexane, 1,3,5-trinitrobenzene, 1,3-dinitrobenzene, nitrobenzene, 2,4,6-N-tetranitro-N-methylaniline, Trinitrotoluene, 4-amino-2,6-dinitrotoluene, 2-amino-4,6-dinitrotoluene, 2,6-dinitrotoluene, 2,4-dinitrotoluene, 2-nitrotoluene, 4-nitrotoluene, and 3-nitrotoluene) and/or five inorganic cations (Na(+), NH(4)(+), K(+), Mg(2+), and Ca(2+)) using liquid chromatography linked to ion chromatography by a switching valve. The mobile phase was methanol-water (40/60, v/v) for a C18 reversed-phase column and 3 mM of methanesulfonic acid (pH 2.5) for a cation-exchange column, respectively. Under the optimal conditions, the 14 organic explosives and the five inorganic cations were separated and detected simultaneously within 45 min. The limits of detection (S/N = 3) of the 14 organic explosives and the five inorganic cations were in the range of 0.0048-0.0333 mg/L and 0.0116-0.1851 mg/L, respectively. The linear correlation coefficients were 0.9971-0.9999, and the relative standard deviation of the retention time and the peak area were 0.02-0.31% and 0.51-3.64%, respectively. The method was successfully applied to the determination of organic explosives and inorganic cations in dust samples.     

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.     

分解反应自催化性质快速鉴别的实验方法

许多物质的分解都具有自催化特性,常用的自催化鉴别方法是利用差示扫描量热仪（DSC）、微量量热仪（C80）等进行等温实验判定（简称“等温法”）. 但等温法的温度选择较为困难,因此很有必要从实验角度找到一种简便有效的自催化鉴定方法. 本文基于Roduit理论模拟的结果,从实验角度提出了分解反应自催化特性的判定方法（简称“中断回扫法”）,并利用该法以及等温法对4种样品（硝酸异辛酯（EHN）、2,4-二硝基甲苯（2,4-DNT）、过氧化二异丙苯（DCP）以及过氧化氢异丙苯（CHP））的分解特性进行判定. 结果表明：EHN以及DCP的分解符合n级分解规律,而2,4-DNT以及CHP的分解符合自催化分解规律;中断回扫法可以快速、有效地用于鉴别物质分解是否具有自催化特性.     

分解反应自催化性质快速鉴别的实验方法

许多物质的分解都具有自催化特性,常用的自催化鉴别方法是利用差示扫描量热仪(DSC)、微量量热仪(C80)等进行等温实验判定(简称"等温法").但等温法的温度选择较为困难,因此很有必要从实验角度找到一种简便有效的自催化鉴定方法.本文基于Roduit理论模拟的结果,从实验角度提出了分解反应自催化特性的判定方法(简称"中断回扫法"),并利用该法以及等温法对4种样品(硝酸异辛酯(EHN)、2,4-二硝基甲苯(2,4-DNT)、过氧化二异丙苯(DCP)以及过氧化氢异丙苯(CHP))的分解特性进行判定.结果表明:EHN以及DCP的分解符合n级分解规律,而2,4-DNT以及CHP的分解符合自催化分解规律;中断回扫法可以快速、有效地用于鉴别物质分解是否具有自催化特性.     

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.     

Rapid voltammetric determination of nitroaromatic explosives at electrochemically activated carbon-fibre electrodes

The electrochemical behaviour of some nitroaromatic explosives (2,4,6-trinitrotoluene, TNT; 2,6-dinitrotoluene, 2,6-DNT; 2-nitrotoluene, 2-NT; 2-amino-4,6-dinitrotoluene, 2-A-4,6-DNT; 3,5-dinitroaniline, 3,5-DNA; and nitrobenzene, NB) at electrochemically activated carbon-fibre microelectrodes is reported. Electrochemical activation of such electrode material by repeated square-wave (SW) voltammetric scans between 0.0 and +2.6 V versus Ag/AgCl, produced a dramatic increase in the cathodic response from these compounds. This is attributed to the increase of the carbon-fibre surface area, because of its fracture, and the appearance of deep fissures along the main fibre axis into which the nitroaromatic compounds penetrate. Based on the important contribution of adsorption and/or thin layer electrolysis to the total voltammetric response, a SW voltammetric method for rapid detection of nitroaromatic explosives was developed. No interference was found from compounds such as hydrazine, phenolic compounds, carbamates, triazines or surfactants. The limits of detection obtained are approximately 0.03 g mL^–1 for all the nitroaromatic compounds tested. The method was applied for the determination of TNT in water and soil spiked samples; recoveries were higher than 95% in all cases.     

Solid-phase microextraction (SPME) calibration using inkjet microdrop printing for direct loading of known analyte mass on to SPME fibers

Solid-phase microextraction (SPME) is a widely used sampling technique that has been proved to enable efficient extraction of a broad range of analytes. Generally, SPME achieves non-exhaustive extraction, and therefore the analyte mass transfer distribution in the sampled multiphase system should be considered while developing a calibration method. Here, a new method, aimed at quantifying the extracted analytes without the need to consider their mass distribution, is proposed. This method relies on the generation of mass response curves by loading a known analyte mass onto the absorbent phase of a SPME fiber, and then conducting analysis by the preferred technique. Precise and accurate deposition of analyte over the restricted dimension of a fiber is demonstrated for the first time by utilizing a drop-on-demand microdrop printer. This system enables direct, non-contact deposition of micron-sized drops containing negligible solvent volumes (<1 nL), on the center of the extraction phase of the fiber which enables immediate analysis. Printed fiber response curves were determined herein, with three model compounds of different volatility—2,4-dinitrotoluene (2,4-DNT), diphenylamine (DPA), and 1,3 diethyl-1,3-diphenylurea (ethyl centralite, EC), using two analytical techniques, gas chromatography–mass spectrometry (GC–MS) and ion mobility spectrometry (IMS). Quantification of the absolute amounts extracted by headspace SPME yielded comparable results between the two methods of analysis with only less than 10% variation for 2,4-DNT and EC and less than 30% for DPA. In comparison, quantification by the traditional liquid injection/spike response curves determined by each technique led to mass estimates that were significantly greater by hundreds of percent.     

On-line strategies for determining trace levels of nitroaromatic explosives and related compounds in water

We report the development and tests of several systems for the simultaneous determination of 18 energetic compounds and related congeners in untreated water samples. In these systems a Restricted Access Material trap or liquid-chromatography precolumn (with a C(18) or porous graphitic carbon, PGC, stationary phase) followed by a PGC analytical column are used for sample clean-up, enrichment and separation of the trace level analytes, which are then analyzed by mass spectrometry (MS). The relative merits of two MS ionization interfaces (atmospheric pressure chemical ionization, APCI, and atmospheric pressure photoionization, APPI) were also compared for the MS identification and quantification of these analytes. APCI was found to be superior in cases where both alternatives are applicable. A major drawback when applying APPI is that no signal is obtained for the cyclic nitramines and nitrate esters. Using APCI, a wide spectrum of unstable compounds can be determined in a single analysis, and the feasibility of using large volume samples (up to 100 mL) in combination with the sensitivity of the MS detection system provide method detection limits ranging from 2.5 pg/mL (for 2,4-dinitrotoluene and 2,6-diamino-6-nitrotoluene) to 563 pg/mL (for pentaerythritol tetranitrate, PETN), with repeatability ranging from 2 to 7%. Other chemometric parameters such as robustness, selectivity, repeatability, and intermediate precision were also evaluated in the validation of the extraction methods for use in water analysis. Tests with untreated groundwater and drinking water samples, spiked with 20 ng of the analytes, yielded results similar to those obtained with high purity water samples.