Klaus Steinbach

Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine: I. Derivatization

A procedure for the enrichment of aromatic amines via solid-phase extraction was developed. A HR-P phase based on styrene-divinylbenzene was used for the investigations, generally followed by derivatization with iodine and determination via GC-ECD. The recoveries of 53 aromatic amines in a drinking water matrix at pH 9 were determined. Most anilines showed relative recoveries between 80-120% with relative standard deviations of< or = 5% at concentration levels between 10 and 20 micrograms 1(-1). The comparison with a wastewater matrix led to similar results. The enrichment procedure was applied to real samples, e.g., samples of ammunition wastewater.

Toxicological characterization of 2,4,6-trinitrotoluene, its transformation products, and two nitramine explosives

The soil and groundwater of former ordnance plants and their dumping sites have often been highly contaminated with the explosive 2,4,6-trinitrotoluene (2,4,6-TNT) leading to a potential hazard for humans and the environment. Further hazards can arise from metabolites of transformation, by-products of the manufacturing process, or incomplete combustion. This work examines the toxicity of polar nitro compounds relative to their parent compound 2,4,6-TNT using four different ecotoxicological bioassays (algae growth inhibition test, daphnids immobilization test, luminescence inhibition test, and cell growth inhibition test), three genotoxicological assays (umu test, NM2009 test, and SOS Chromotest), and the Ames fluctuation test for detection of mutagenicity. For this study, substances typical for certain steps of degradation/transformation of 2,4,6-TNT were chosen for investigation. This work determines that the parent compounds 2,4,6-TNT and 1,3,5-trinitrobenzene are the most toxic substances followed by 3,5-dinitrophenol, 3,5-dinitroaniline and 4-amino-2-nitrotoluene. Less toxic are the direct degradation products of 2,4,6-TNT like 2,4-dinitrotoluene, 2,6-dinitrotoluene, 2-amino-4,6-dinitrotoluene, and 4-amino-2,6-dinitrotoluene. A weak toxic potential was observed for 2,4,6-trinitrobenzoic acid, 2,4-diamino-6-nitrotoluene, 2,4-dinitrotoluene-5-sulfonic acid, and 2,6-diamino-4-nitrotoluene. Octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazocine and hexahydro-1,3,5-trinitro-l,3,5-triazine show no hint of acute toxicity. Based on the results of this study, we recommend expanding future monitoring programs of not only the parent substances but also potential metabolites based on conditions at the contaminated sites and to use bioassays as tools for estimating the toxicological potential directly by testing environmental samples. Site-specific protocols should be developed. If hazardous substances are found in relevant concentrations, action should be taken to prevent potential risks for humans and the environment. Analyses can then be used to prioritise reliable estimates of risk.

Identification of Oxidized TNT Metabolites in Soil Samples of a Former Ammunition Plant

Water extracts of soil samples of the former ammunition plant “Tanne” near Clausthal-Zellerfeld, Lower Saxony, Germany, were investigated for highly polar oxidized 2,4,6-trinitrotoluene (TNT) metabolites. 0.4 to 9.0 mg/kg dry soil 2,4,6-trinitrobenzoic acid (TNBA) and 5.8 to 544 mg/kg dry soil 2-amino-4,6-dinitrobenzoic acid (2-ADNBA) were found. In addition to the oxidized metabolites, TNT, 4- and 2-aminodinitrotoluene (4- and 2-ADNT), and 2,4-dinitrotoluene (2,4-DNT) were extractable with water. Most interestingly, in one sample, 2-ADNBA represented the main contaminant.The origin of the oxidized nitroaromatics is unknown at this time. They might be generated chemically or photochemically. Furthermore, a biological synthesis seems possible.

Highly polar metabolites of nitroaromatic compounds in ammunition wastewater.

Transformation processes of nitroaromatic compounds (NAC) are described that lead to polar and highly hydrophilic metabolites in ammunition waste water. For the identification of proposed metabolites, several analytical methods for the separation and determination of these compounds were developed and applied to the investigation of a former ammunition plant and its surroundings. The compound classes which were investigated include nitro and amino substituted toluenesulfonic acids, nitrobenzoic acids, aminobenzoic acids and nitromethylphenols. Method development was usually done with high performance liquid chromatography and ion pairing or ion suppression techniques. In the leachate water of a disposal site of a former ammunition plant in Stadtallendorf, Germany, 15 compounds from the above-mentioned categories have been found to be present in concentrations up to a few hundred microgram/L. The presence of so many polar compounds suggest that current and future surveying programs should include representative analytes of the investigated categories.

Derivatization of aromatic amines with bromine for improved gas chromatographic determination

SummaryFor improved determination of aromatic amines by gas chromatography and detection with an electron capture detector (GC-ECD) a derivatization method based on the bromination of the aromatic ring in an acetic acid medium was developed. In general, all free ortho and para-positions relative to the amino group undergo electrophilic substitution. Separation of at least 30 compounds in a single chromatographic run in 30 min is possible. With this method, 56 aromatic amines were studied and only in 6 cases were no derivatives obtained. Quantitation limits determined from calibration data are 1.2–40 μg L−1 for a 100 mL sample and an injection volume of 1 μL. Previous experiments suggest that both sample and injection volume may be increased to lower the quantitation limit.

Determination of Aromatic Amines in Ground and Waste Water by Two New Derivatization Methods

Abstract Two derivatization methods for aromatic amines are presented that are based on the halogenation of the aromatic ring. Bromination yields brominated anilines, in which all hydrogens in ortho- and para-positions are replaced by bromine via an electrophilic substitution. In contrast, iodination yields the corresponding iodobenzenes, in which all amino groups are substituted by iodine. Separation of at least 30 derivatives in a single gaschromatographic run in 30 min is possible with each method. Detection in routine analysis was done with an electron capture detector, but some findings with GC-MS and GC with atomic emission detection are also presented. Both methods were applied to real samples of different origin and the results are compared. In industrial wastewater and ground water from a landfill and a former ammunition plant, about 20 aromatic amines were found to be present in the μg/L concentration range. In the case of the former ammunition plant, most analytes observed were degradation prod...

Synthesis of reference substances for highly polar metabolites of nitroaromatic compounds

Transformation processes of nitroaromatic compounds (NAC) lead to polar and highly hydrophilic metabolites. For the unequivocal identification of proposed metabolites reference substances are needed. Since most of them are not commercially available, their synthesis was done in our group. In many cases no satisfying synthesis schemes were found in the literature. In this communication, we therefore describe the preparation, structural elucidation and separation of 17 compounds. Many of the newly synthesized analytes were found in various water samples from a former ammunition plant.

Formyl migration product of chanoclavine-I aldehyde in the presence of the old yellow enzyme FgaOx3 from Aspergillus fumigatus: a NMR structure elucidation.

A previous study showed that together with the festuclavine synthase FgaFS, the old yellow enzyme FgaOx3 from Aspergillus fumigatus catalyzed the conversion of chanoclavine‐I aldehyde to festuclavine in the biosynthesis of ergot alkaloids. In the absence of FgaFS, a mixture containing two compounds with a ratio of 7:3 was detected in the enzyme assay of FgaOx3. NMR experiments including (DQF)‐COSY, HSQC, HMBC and NOESY identified their structures as E/Z isomers of N‐methyl‐N‐[(5R,10R)‐10‐(2‐oxo‐propyl)‐2,4,5,10‐tetrahydrobenzo[cd]indol‐5‐yl]formamide and proved the migration of the formyl group at C‐8 in chanoclavine I‐aldehyde to N‐6 in the identified products. Copyright

Anaerobic Degradation and Transformation of p-Toluidine by the Sulfate-Reducing Bacterium Desulfobacula toluolica

Abstract. The ability of the strictly anaerobic sulfate-reducing bacterium Desulfobacula toluolica (strain Tol2) to cometabolically degrade p-toluidine (p-methylaniline) while using toluene as the primary source of carbon and energy has been studied. This organism has been shown to modify and degrade toluidine in dense cell suspensions when no other source of carbon and energy is added. The metabolism led to the formation of a variety of metabolites. From these metabolites a biphenyl-like compound as well as phenylacetic acid have been identified by means of HPLC/MS techniques. The probable conversion of p-toluidine to p-aminophenylacetic acid and phenylacetic acid as dead end products suggested that this organism initiates p-toluidine degradation by the carboxylation of the methyl group. If this could be validated in further experiments, it would be the first time that a toluidine was carboxylated at the methyl moiety by an anaerobic, sulfate-reducing bacterium.

Chemisch-analytische Untersuchung von Arsenkampfstoffen und ihren Metaboliten

ZusammenfassungArsenkampfstoffe sind in der Umwelt persistent und kontaminieren bis heute Boden und Grundwasser. In diesem Beitrag werden die chemischen Reaktionen der Arsenkamptstoffe Diphenylarsinchlorid (CLARK I), Phenylarsindichlorid (PFIFFIKUS), Ethylarsindichlorid (DICK) sowie von Chlorvinylarsinverbindungen (LEWISITE) dargestellt. Die Möglichkeiten der chemisch-analytischen Erfassung dieser chemischen Kampfstoffe als Originalsubstanzen und als Thiol-Derivate werden präsentiert.AbstractArsenic containing chemical warfare agents (cwa) are persistent in the environment and continue to contaminte soil and ground water. In this paper the chemical rections of the cwa diphenylarsine chloride (CLARK I), phenylarsine dichloride (PFIFFIKUS), ethylarsine dichloride (DICK) and of chlorovinyl arsenic compounds (LEWISITE) are shown. The posibilities of the detection and determination of this cwa and their metabolites are presented.