Dinitrotoluene Isomers Research Articles

Effect of toluidines and dinitrotoluenes on caffeine metabolic ratio in rat

Caffeine (1,3,7-trimethylxanthine, CA) is metabolised by N-demethylation to three primary metabolites: theophylline (TP), paraxanthine (PX) and theobromine (TB). This process is mediated in 95% by CYP1A2. Thus the measurement of CA demethylated metabolites can be used as a marker of CYP1A2 activity in vivo. In the present study, caffeine and its primary metabolites were determined simultaneously in plasma of rats pretreated with three isomers of toluidine at doses: 1, 10, 60 mg/kg b.w., p.o. and four isomers of dinitrotoluene (DNT) at doses: 100 and 200 mg/kg b.w., p.o. Caffeine metabolite ratios in plasma: TB/CA, PX/CA, TP/CA, TB+PX+TP/CA were calculated and compared to those of control rats. Administration of toluidines resulted in a 2–20 fold increase of the concentration ratios of metabolites to caffeine. All toluidines seem to be inducers of CYP1A2. To the best of our knowledge this is the first information concerning the effect of toluidines on caffeine metabolism. Two out of the four tested dinitrotoluenes slightly affected CYP1A2 activity; 2,3- and 3,4-DNT increased estimated parameters 2–6 fold. Two others, 2,4- and 2,6-DNT can be considered as moderate hepatotoxic agents decreasing CA metabolic ratios to 4–70% of the control values.

Ultra-rapid soil screening with the use of GC-SAW technology for TNT/DNT and related nitroaromatic contaminants

A method for the preliminary identification and quantitation of 2,4,6-trinitrotoluene (TNT) and the isomers of dinitrotoluene (DNT) from contaminated soils is described. Ultra-rapid gas chromatography (GC) was used to detect the analytes of interest that can generate a chromatogram in 10 s or less, distinguishing the analytes of interest. The instrument uses a 0.5-m-long capillary GC column with laptop computer control of thermal gradients and operating methods. Detection of the effluent analyte vapors from the helium (He) carrier gas stream of the GC is performed with the use of a surface acoustic wave detector (SAW). Instrument run times of less than 2 min provide almost real-time detection of soil-generated vapors, thereby enabling possible field surveys of munitions-contaminated soil samples. Additionally, by taking readings over a longer period of time while the soil sample is thermally desorbed, the total concentration of the various components can be calculated by integrating the derived signals of multiple chromatograms and comparing these to a known quantity of desorbed TNT. This protocol allows for the approximate quantitation of nitroaromatics with the possibility of field applications. The extremely rapid acquisition of data allows for site mapping and acquisition of pertinent samples for further, more extensive examination.

An Electrochemiluminescence Assay Based on the Interactionof Diaminotoluene Isomers with Gold(I) and Copper(II) Ions

A novel assay for the determination of 2,4- and 3,4-diaminotoluene (DAT) isomers based on the low-level electrochemiluminescence (ECL) reaction of these molecules with the group IB transition metal ions Au+and Cu+2, respectively, in aqueous solution is described. DAT isomers were screened for ECL against a repertoire of 32 metals, including metal ions such as Cu+2, Eu+3, Mg+2, Ru+3, and Tb+3associated with other known ECL complexes, at 1:3 added metal ion:ligand molar ratios. The 1:3 molar ratio presumed tris-bidentate octahedral metal coordination complex formation, which generally yielded optimal ECL intensity. The apparent specificity of Au+for 2,4-DAT and Cu+2for 3,4-DAT, as indicated by ECL measurements, may be partly based on ionic size as Au+has nearly twice the ionic diameter of Cu+2and thus may form a coordination complex with themeta,but not theorthoDAT. Other DAT isomers were screened and exhibited mildly enhanced ECL with various metal ions, including group IB transition metal ions, but these ECL enhancements were not statistically significant. In some cases, titration of DAT ligands with Cu+2and Au+over broad concentration ranges produced nonlinear ECL response curves. Despite low-level ECL, sensitivities in the ppm range for Au+, Cu+2, and their respective DAT isomers were achieved. Time dependence was observed for some of the ECL reactions, including the Ru(III)–bipyridine model system, in which the ECL intensity grew markedly over several hours. No ECL enhancements over background were observed with two dinitrotoluene isomers or an aminonitrotoluene screened against the same set of 32 metals. This novel ECL approach may have applications in the determination of some aminoaromatics from degradation of explosives (e.g., TNT) as well as detection and quantitation of various transition metals in industrial wastewater streams and groundwater supplies. In terms of fundamental science, the present data are probably of interest as an example of size-dependent molecular recognition of metal ions which can be detected by ECL.

Ab initio studies of the molecular structures of dinitrotoluenes

The molecular structures of six positional dinitrotoluene isomers were calculated by an ab initio HF/6-31G ∗ method. Different deformations of the phenyl ring and distortions of the nitro and methyl groups with the ring of each isomer were observed. Deformations of the benzene ring did not completely match the rule predicted by Domenicano et al. In addition to the inductive and resonance effects, steric effects also play an influential role in the deformation of the phenyl ring and the distortion of the substitution groups with the ring. Calculated energies indicated that of all the dinitrotoluene isomers 3,5-dinitrotoluene is the most stable molecule and 2,3-dinitrotoluene is the most unstable. Comparison of the calculated energies of all isomers revealed a tendency that a stable isomer is found when the steric effect is reduced. Intramolecular hydrogen bonds were also analyzed for some isomers; their strengths were, however, found to be weak.

A Survey of High Explosives Traces in Public Places

Abstract This survey was carried out to determine the background levels of explosives traces in public places. Samples were taken at various transport sites. Police sites were also sampled to assess how likely it is that a suspect could be contaminated. The survey showed that traces of the high explosives nitroglycerine (NG), trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and cyclotrimethylene trinitramine (RDX) are rare within the general public environment. Only four low level traces of RDX were detected. NG, probably associated with the use of firearms, was detected at a number of police sites, but traces of other explosives were rare. The results of the survey indicate that it is unlikely that someone in public areas could become significantly contaminated with explosives. Traces of NG found on suspects who have had contact with police sites must be interpreted in the light of the survey results. The analytical procedures used would also have detected ethylene glycol dinitrate (EGDN) if present at levels greater than 2 ng, mononitrotoluenes, if present, at levels greater than 50 ng and the most common isomers of dinitrotoluene if these had been present at levels in excess of 10 ng. None of these were detected. The relatively high volatility of EGDN and the mononitrotoluenes would, however, cause traces of these compounds to disperse rapidly.

Trace analysis of explosives in water by gas chromatography—mass spectrometry with a temperature-programmed injector

Gas chromatography—mass spectrometry with a cooled temperature-programmable injector was used to analyze picogram amounts of explosives in water. The analyzed explosives included 2,4,6-trinitrotoluene (TNT), 2,4,6-N-tetranitro-N-methylaniline (Tetryl), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), pentaerythritol tetranitrate (PETN) and a series of dinitrotoluene (DNT) isomers (which are ingredients of explosives). Thermal decomposition, even in the thermolabile explosives, was minimal. Traces of explosives in water in the range of 5–100 ppb could be detected and identified.

Identification of Dynamite Explosives in Post Explosion Residues

Abstract The investigation of post blast residues of dynamite explosives with respect to the behavior of nitro-aromatic compounds is described. Experimental blasts were performed with free hanging charges. The samples taken from metal plates placed at different distances from the center of the explosion were analyzed by GC-TEA. The results were evaluated with respect to the relative amounts of the dinitrotoluene isomers to each other. The portions of the dinitrotoluenes showed good correspondance in the post blast residues with the original explosives.

The in vitro effects of four isomers of dinitrotoluene on rat Sertoli and Sertoli-germ cell cocultures: Germ cell detachment and lactate and pyruvate production

The present study was undertaken to evaluate the in vitro effects of four isomers of a known testicular toxicant, dinitroluene (DNT). Rat Sertoli or Sertoli-germ cell cocultures were treated, after 3 days in culture, with DNT isomers (0.01 to 100 μ m) or 1,3-dinitrobenzene (1,3-DNB) for 24 hr. Cellular morphology, germ cell detachment (GCD) and lactate pyruvate production were used as sensitive effect markers of in vitro toxicity. Morphologically the Sertoli cell monolayer remained intact 24 hr after exposure to DMSO, 1,3-DNB, or DNT isomers. Some apparent cytotoxicity was observed at 100 μ m 3,4-DNT: the monolayer was disrupted with extensive vacuolation of the Sertoli cells. Cocultures treated with concentrations of 50 μ m DNT isomers closely resembled cells treated with 100 μ m 1,3-DNB. GCD increased in a dose-dependent manner (0.01 and 10 μ m DNT isomers) increasing between 2- and 10-fold over control. Both lactate and pyruvate production increased with rising concentrations of DNT isomers. The most sensitive effect was seen with 3,4-DNT (10 to 25 μ m). In the case of 2,6-DNT, despite increases in GCD and lactate production, only a minimal increase in pyruvate was demonstrated. Overall, the ratio of lactate to pyruvate production declined with increasing doses of DNT. These results indicate that the four isomers of DNT directly affected Sertoli cell morphology and function, effects comparable to those seen with the Sertoli cell toxicant 1,3-DNB. Further, the data support the hypothesis that DNT may be a Sertoli cell toxicant.

Effects of dinitrotoluenes on morphological cell transformation and intercellular communication in Syrian hamster embryo cells

The effects of four isomers of dinitrotoluene (DNT) and technical DNT (a mixture of DNT isomers and other compounds, with 2,4-DNT as the major constituent) were studied in two short-term in vitro assays. None of the isomers or technical DNT induced an increase in morphological transformation of Syrian hamster embryo (SHE) cells. Four DNT metabolites (2,4-diaminotoluene, 2-amino-4-nitrotoluene, 2-amino-6-nitrotoluene, and 2,4-dinitobenzoic acid), representing different stages in reduction or oxidation of DNT isomers, were also negative for induction of morphological transformation. The DNT isomers were tested in an intercellular communication assay based on dye transfer. 2,4-DNT, 2,6-DNT, and technical DNT inhibited intercellular communication in the SHE cell line BPNi at toxic concentrations. This may be reminiscent of in vivo data showing promoting activity of these compound. 2,3-DNT and 3,4-DNT did not inhibit communication.

A new method for in situ crosslinking of stationary phases on fused silica capillary columns

AbstractA new mixed crosslinking agent composed of dicumyl peroxide and tetra(methylvinyl)cyclotetrasiloxane was used to prepare fused silica capillary columns with in situ crosslinked stationary phases including PEG‐20M, SE‐54, and OV‐1. These columns proved to have good thermostability and inertness. As examples of potential applications a mixture of isomers of nitrotoluene and dinitrotoluene, and pyrolyzates of polystyrene were separated by using these columns.

Genotoxic activity of nitroaromatic explosive and related compounds in Salmonella typhimurium

A number of nitroaromatic explosives and related compounds were examined for mutagenic activity with the Salmonella/mammalian microsome test. 9 of 11 nitroaromatics tested were mutagenic, including 2,4,6-trinitrotoluene, the most widely produced military explosive. All the nitroaromatics, except 2,4,6-trinitrophenol and 2,3,5-trinitroresorcinol, were at least an order of magnitude more mutagenic than 3 dinitrotoluene (DNT) isomers. The most active compound was 2,3,5-trinitronaphthalene, which was approximately 5000 times more mutagenic than DNT isomers. These compounds induced predominantly frameshift mutations. The mutagenic activity did not require S9 activation, but was largely dependent on the presence of an intact nitroreductase capability in the test bacteria. This implied that reduced metabolites, possibly hydroxylamines, are the proximal mutagenic intermediates.

Metabolism of dinitrotoluene isomers by Escherichia coli isolated from human intestine.

Technical grade dinitrotoluene (DNT), an important industrial nitroaromatic compound, not only induces methemoglobinemia but is a potent hepatocarcinogen in man and rats. The purpose of the present study was to identify the metabolites produced from five DNT isomers (2, 3-, 2, 4-, 2, 5-, 2, 6-and 3, 4-DNT) by Escherichia coli (E. coli) strain W3110, isolated from human intestine. Data obtained from thin-layer and gas chromatographies or liquid scintillation counting indicated that the metabolites produced by the E. coli were two monoaminonitrotoluenes and hydroxylaminonitrotoluenes in all cases. This finding indicates that DNT is reduced via hydroxylaminonitrotoluenes to monoaminonitrotoluenes in E. coli. In addition, it was found that the reduction reactivities of DNT isomers were 3->2-for 2, 3-DNT, 4->2-for 2, 4-DNT, 5->2-for 2, 5-DNT and 3->4-for 3, 4-DNT. The role of bacterial reduction in the toxic actions of DNT is discussed.

Dinitrotoluene: acute toxicity, oncogenicity, genotoxicity, and metabolism.

Dinitrotoluene (DNT) is a major commodity chemical; over six hundred million pounds of DNT were used in the chemical industry in 1980. Interest in the toxicology of this important chemical was greatly increased when separate oncogenicity assays yielded the conflicting results that DNT was either not hepatocarcinogenic or produced a 100% incidence of hepatocellular carcinomas in male rats in one year. Research revealed pronounced differences in the activity of the DNT isomers and provided the reason for the dissimilar results of the various carcinogenicity studies. Cell culture genetic toxicology assays failed to predict the potent carcinogenic activity of any isomer of DNT. Only when the complex pattern of metabolic activation of DNT began to unfold and genotoxic activity was assessed in the appropriate target organ in the intact treated animal was the potent genotoxic activity of DNT revealed, and the reasons for the negative in vitro results understood. The DNTs have been extensively tested for reproductive effects in animals and humans, and the metabolism and disposition of each of the six possible isomers have been studied. This work has provided valuable information in establishing the risk of these compounds to humans.

The reduction of propyleneglycol dinitrate, nitroglycerin, dinitrotoluene, and trinitrotoluene on silver electrodes

The nitrate esters propyleneglycol 1,2-dinitrate and nitroglycerin, as well as the aromatic nitro compounds, dinitrotoluene and trinitrotoluene, are electrochemically reducible on silver electrodes. Concentrations as low as 0.5 mg l −1 are readily detectable at scan rates of 5 mV s −1 in unstirred solutions. Peak potentials vary with the nature of the electrolyte anion. The ortho, meta, and para isomers of dinitrotoluene yield different voltammograms; the ortho and para isomers show two reduction peaks but only a single peak is found for the three meta isomers. Constant-current, exhaustive electrolysis studies of 2,5-dinitrotoluene show two reduction stages, corresponding to three-electron and five-electron reductions.

Hydrogen bonding of dinitrotoluene isomers to unesterified hydroxyl groups in nitrocellulose

Hydrogen bonding of dinitrotoluene isomers to unesterified hydroxyl groups in nitrocellulose

Metabolism of 2,4-dinitrotoluene by intestinal microorganisms from rat, mouse, and man

Dinitrotoluene (DNT) is an industrial chemical of importance in the production of urethane foams and elastomers. The technical grade material is a hepatocarcinogen in rodents but shows sex- and species-dependent differences in potency. We have studied the pathways of metabolism of 2,4-dinitrotoluene (2,4-DNT), the major component of technical material, in the cecal microflora of male rats, female rats, male mice, and in human feces and ileal contents. 2,4-DNT was not metabolized by any of these preparations in the presence of oxygen. Under anaerobic conditions an ordered sequence of reductive metabolism was observed. The 2- and 4-nitro groups were reduced to amino groups via nitroso intermediates which were identified by GC-MS. The reduction of the nitroso intermediate to the amino compound is presumed to involve a hydroxylamino intermediate which could not be isolated. The aminonitro compounds were then reduced to diaminotoluene. No intermediates in this sequence could be isolated. No sex- or species-dependent differences in the pathways of metabolism were observed and only small species-dependent differences in the rate of metabolism of 2,4-DNT were observed. It is concluded that the intestinal microflora of rodents represent the major site of reductive metabolism of 2,4-DNT and may play an important role in the carcinogenic action of DNT isomers.

The Use of In vivo Hepatic Initiation-Promotion Systems in Understanding the Hepatocarcinogenesis of Technical Grade Dinitrotoluene.

A 2 year bioassay sponsored by the Chemical Industry Institute of Toxicology demonstrated the potent hepatocarcinogenicity of technical grade dinitrotoluene (DNT) which contains 76% 2,4-DNT, 18% 2,6-DNT and less than 3% of each 2,3; 2,5; 3,4 and 3,5-DNT isomers. In contrast, a 2 year bioassay of 2,4-DNT sponsored by the National Cancer Institute did not result in the appearance of hepatic neoplasms above the spontaneous incidence. Using previously described in vivo hepatic initiation-promotion systems, an evaluation of the initiating and promoting activity of individual DNT isomers was undertaken to provide an understanding for the differences between the two bioassays. Weak hepatocyte initiating activity was identified in technical grade DNT and purified 2,6-DNT. In contrast, 2,3; 2,4; 2,5; 3,4 and 3,5 isomers had no detectable initiating activity. When fed following a diethylnitrosamine initiating regimen, technical grade DNT, purified 2,4 and 2,6-DNT isomers had demonstrable promoting activity. Therefore, the hepatic neoplasms resulting from technical grade DNT feeding apparently resulted from the initiating activity of 2,6-DNT followed by the promoting effect of both the 2,4 and 2,6-DNT isomers. The lack of hepatic neoplasms following chronic feeding of 2,4-DNT was apparently due to the lack of hepatic initiating activity.

The Use of In vivo Hepatic Initiation-Promotion Systems in Understanding the Hepatocarcinogenesis of Technical Grade Dinitrotoluene

A 2 year bioassay sponsored by the Chemical Industry Institute of Toxicology demonstrated the potent hepatocarcinogenicity of technical grade dinitrotoluene (DNT) which contains 76% 2,4-DNT, 18% 2,6-DNT and less than 3% of each 2,3; 2,5; 3,4 and 3,5-DNT isomers. In contrast, a 2 year bioassay of 2,4-DNT sponsored by the National Cancer Institute did not result in the appearance of hepatic neoplasms above the spontaneous incidence. Using previously described in vivo hepatic initiation-promotion systems, an evaluation of the initiating and promoting activity of individual DNT isomers was undertaken to provide an understanding for the differences between the two bioassays. Weak hepatocyte initiating activity was identified in technical grade DNT and purified 2,6-DNT. In contrast, 2,3; 2,4; 2,5; 3,4 and 3,5 isomers had no detectable initiating activity. When fed following a diethylnitrosamine initiating regimen, technical grade DNT, purified 2,4 and 2,6-DNT isomers had demonstrable promoting activity. Therefore, the hepatic neoplasms resulting from technical grade DNT feeding apparently resulted from the initiating activity of 2,6-DNT followed by the promoting effect of both the 2,4 and 2,6-DNT isomers. The lack of hepatic neoplasms following chronic feeding of 2,4-DNT was apparently due to the lack of hepatic initiating activity.

Sources and behaviour of dinitrotoluene isomers in sea-water

The sources and behaviour of dinitrotoluene (DNT) isomers in the sea-water of Dokai Bay in Japan were investigated. DNT isomers such as 2,6-, 2,5-, 2,4-, 2,3- and 3,4-DNT were identified in an industrial effluent. One drain, the main source, discharged about 150 kg of DNT isomers as the maximum value in a day. This value roughly agrees with that obtained from seven months of monitoring of DNT isomers in sea-water. The monitoring revealed that about 76 kg of DNT isomers was discharged into the bay daily. 2,6-, 2,4- and 2,3-DNT were detected in the sea-water at the levels of 14,8-ND μg l −1 ( n = 82), 206-ND μg l −1 ( n = 82) and 0.412-ND μg l −1 ( n = 82), respectively. The relationship between the concentration of 2,4-DNT ( Y) and the distance ( X) is statistically expressed by the equation of Y = (6.38 ± 4.02)e −(0.269 ± 0.044) X , and the relationship between the 2,6-DNT/2,4-DNT ratio ( y) and the distance ( X) is expressed as y = −(0.795 ± 0.131) X + (9.35 ± 4.1). These relationships reveal that the decrease of DNT isomers in the sea-water is caused by factors more complex than mechanical dilution by tidal action.

Metabolism of 2,4-dinitrotoluene by rat hepatic microsomes and cecal flora.

Dinitrotoluene (DNT) is an industrial chemical used as an intermediate in the production of toluene diisocyanate for the manufacture of polyurethane foams, coatings and elastomers. Technical grade DNT is a potent hepatocarcinogen which produces a dose related incidence of hepatocellular carcinoma in Fischer 344 rats (CIIT, 1979). The technical grade material comprises approximately 75% 2,4-DNT, 19.5% 2,6-DNT and 4% other DNT isomers with small amounts of mono-and tri-nitrotoluenes and nitrocresols also present. The major component of the technical grade material, 2,4-DNT, has also been demonstrated to be a hepatocarcinogen in CD-1 rats (Ellis et al., 1979).KeywordsHepatic MicrosomeAnaerobic IncubationMixed Function OxidaseCecal ContentNitro TolueneThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.