Nitroaromatics determination

Aromatic amines from the (bio)degradation of azo dyes or nitroaromatic explosives must also be monitored, mainly through the sum of their concentrations. However, taking account of the standard solution used for the calibration of the colorimetric reference method (4-nitroaniline), some attempts are proposed for the on-line specific determination of the most important single compounds [44,45]. 

Walsh ME. Determination of nitroaromatic, nitramine, and nitrate ester explosives in soil by gas chromatography and electron capture detector. Talanta 2001 54 427-438. 

A comparison of active (using pumps) and passive (relying on diffusion) sampling techniques for the determination of nitrobenzene, benzene and aniline in air was mentioned in Section IV.A77. Several LLE methods for nitroaromatic compounds dissolved in water were evaluated. High recoveries were achieved with discontinuous or continuous extraction with dichloromethane, adsorption on a 1 1 1 mixture of Amberlite XAD-2, -4 and -8 resins and elution with dichloromethane445. 

A sensitive ELISA procedure was developed for the determination of TNT (221) and other nitroaromatic compounds. TNT can be detected within the range of 0.02-20 ng/L in water samples462. A simplified immunofiltration prepacked portable device for field screening tests of TNT in water and soil was also developed. A quantitative color response to concentrations of TNT in the range 1-30 ng/L in water and 50-1000 pg/g in soil was demonstrated463. 

Only the silica-based stationary phases with covalently bonded alkyl chain, cyano and propylamino ligands have found practical applications in HPLC. Besides these common ligands, the experimental use of naphthalene, pyrene and nitroaromatic as ligands has also been reported. Silica-based stationary phases with covalently bonded cyclodextrins or cyclodextrin derivatives have been frequently employed in the separation and quantitative determination of isomer pairs. 

Determination of Certain Nitroaromatics and Isophorone in Municipal and Industrial Discharges using LLE and GC... 

A. L. Lafleur and K. M. Mills, Trace level determination of selected nitroaromatic compounds by gas chromatography with pyrolysis/chemiluminescent detection. Analytical Chemistry, 1981,53, 1202-1205. 

Teltes J, Levsen K. 1989. Reversed phase high-performance liquid chromatographic determination with photodiode-array detection of nitroaromatics from former ammunition plants in surface waters. J High Resolut Chromatogr 12 613-619. 

Teltes J, Levsen K, Volmer D, et al. 1990. Gas chromatographic and mass spectrometric determination of nitroaromatics in water. J Chromatogr 518 21-40. 

Jenkins TF, Walsh ME, Schumacher PW, et al. 1989. Liquid chromatographic method for determination of extractable nitroaromatic and nitramine residues in soil. J Assoc Off Anal Chem 72 890- 899. 

Concentrations of the gaseous nitroarenes, 1- and 2-nitronaphthalene, and 3-nitrobiphenyl in these 18 samples were determined concurrently with the PAHs, in this case sampling with a Teflon-impregnated glass fiber filter (TIGF)/polyurethane foam (PUF) apparatus (Fig. 10.4). The PUF plugs quantitatively trapped the gas-phase nitroaromatics, but not naphthalene and biphenyl and several 3-ring PAHs. 

Heats of Formation of Solid Nitroaromatics. In principle, there are two methods of using group additivity to determine heats of formation of solids. If the groups are available, then the heat of formation of the ideal gas can be calculated. 

Kerckaert, G.A., LeBoeuf, R.A. Isfort, R.J. (1998) Assessing the predictiveness of the Syrian hamster embryo cell transformation assay for determining the rodent carcinogenic potential of single ring aromatic/nitroaromatic amine compounds. Toxicol. Sci., 41, 189-197... 

Shafer KH. 1982. Determination of nitroaromatic compounds and isophorone in industrial and municipal waste waters. U.S. EPA, Off Res Dev, 1-71. 

Nitroaromatics and Isophorone (Method 609). The GC column used for determination of these compounds is essentially the same as that used for the pesticides and PCBs. Nitrobenzene and isophorone are determined at 85 °C by using a FID. 2,6-Dinitrotoluene and 2,4-dinitrotoluene are determined at 145 °C by using an EC detector. 

Extensive research has contributed to the recent development of treatment processes for the bioremediation of soils and waters contaminated with nitro-substituted explosives. By elucidating the degradative pathways in both aerobic and anaerobic systems, we can determine the fate of the parent molecule and assess its effects on the environment. Further research into treating soil contaminated with various nitroaromatics is essential, since their incineration is not always a viable option, due to high cost and risk of pollution. 

By treating styrylated PCTFE with concentrated nitric and sulfuric acids, the corresponding nitrated polymer was obtained (Equation 10). In accordance with the IR spectrum of the resulting polymer (Figure 8), bands at 1529 and 1350 cm-1 indicated the nitro group and a band at 856 cm- confirmed the presence of the nitroaromatic compound. However, the extent of nitration was not determined. 

Figure 4 shows the recoveries of the 19 haloethers. Overall, the recoveries were quite good (averaging around 70 percent across the 19 compounds) but the agreement between the duplicate extractions performed in parallel was not as good as in the case of the nitroaromatics, however, it was within 15 percent for most compounds. To determine if the pressure had any effect upon recovery, we compared experiments 5,6 with experiments 9,10 because they were pairs (performed in parallel at different pressures) and they were performed with sand samples spiked under identical conditions. All recoveries were slightly higher when extractions were performed at lower pressures. This seems to be in contradiction with what we obtained for experiments 7,8 however, in this case the sand was spiked directly in the extraction vessel and therefore, the data from experiments 7,8 cannot be compared with the data from experiments 5,6. 

Figure 11 illustrates the parameter space defined by the equilateral triangle. The initial pressure and conditions for the 3 vertices of the pressure gradient/ temperature triangle were determined arbitrarily from the critical conditions of the supercritical fluid (carbon dioxide), the retention characteristics of nitroaromatic compounds, and the following criteria (i) the first analyte should not co-elute with the sample solvent and (ii) the retention factor of the last analyte should not exceed 30. 

There can be found good reviews on conventional and microchip capillary electrophoresis in forensic/security analysis [4 7] in the literature. The aim of this chapter is to overview the progress which has been made towards the development of portable microfluidic device for on-site and fast detection of nitrated explosives and to describe the major developments in this field (summarized details on analytical methods for microchip determination of nitroaromatic explosives can be found in Table 35.2). The corresponding practical protocol for measurements of explosives on microfluidic device with amperometric detector is described in Procedure 49 (see CD accompanying this book). 

From the selectivity point of view, LC-NMR coupling is especially suited to the analysis of compound classes such as nitroaromatics, phenols, aromatic amines, aromatic carboxylic acids, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and azo- and anthraquinone dyes. Another advantage of LC-NMR coupling for the investigation of aromatic compounds in environmental samples is that the position of substituents on the aromatic ring, e.g. in unknown metabolites or degradation products, can best be determined by NMR spectroscopy. 

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