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PubMed1996

Spectroscopic and elemental investigation of microbial decomposition of aquatic fulvic acid in biological process of drinking water treatment.

As humic substances left in treated water tend to form trihalomethans during chlorination, their removal in water treatment processes is a significant concern for drinking water supplies. One of the removal technologies, the biofilm reactor is studied for the microbial decomposition of aquatic fulvic acid (AFA). The AFA is characterized by elemental analysis. UV-Vis, 13C-NMR, and IR spectroscopic methods. The spectroscopic and elemental investigation was capable of characterizing the microbial decomposition of AFA. Biologically treated fulvic acid was in a more oxidized state; its spectra displayed a higher degree of condensation of aromatic constituents than influent fulvic acid. Microbial degradation of AFA was more active in the low molecular weight fractions and intensively occurred in the aliphatic fraction.

Benzopyrans↗
PubMed1991

Structure/activity investigations in eight arylalkyltriazenes comparison of chemical stability, mode of decomposition, and SCE induction in Chinese hamster V79-E cells.

A series of seven 1-aryl-3.3-dialkyltriazenes, including 1-phenyl-3.3-dimethyltriazene (DMPT), 1-phenyl-3.3-di-(trideuteromethyl)-triazene (DMPT-ds), 1-p-methylphenyl-3.3-dimethyltriazene (DMpMPT), 1-p-nitrophenyl-3.3-dimethyltriazene (DMpNPT), 1-phenyl-3.3-diethyltriazene (DEPT), 1-phenyl-3.3-di-n-propyltriazene (DnPrPT) and 1-phenyl-3.3-diisopropyltriazene (DiPrPT) and 1.3-diphenyl-3-methyltriazene (DPMT), was synthesized and characterized by UV/VIS, IR and 1H-NMR spectroscopy. Chemical half-life was determined in phosphate buffer at 37 degrees using UV/VIS spectroscopy. With the exception of DMpNPT, which was stable, the triazenes underwent pH-dependent hydrolytic decomposition (acid catalysis). By means of UV/VIS spectra, TLC and HPLC, phenol, aniline and secondary azocoupling products were identified after complete hydrolytic cleavage of the parent compounds. Pathways of spontaneous hydrolysis are proposed and discussed. Genotoxic activity of the triazenes was assayed by measurement of sister chromatid exchanges (SCE) in V79-E cells without and with rat liver S9 mix as an exogenous metabolizing system. In the direct SCE assay (without S9 mix), all triazenes except DMpNPT exerted a toxic action (cell cycle delay) in a narrow concentration range between no effect and overt cytotoxicity. This non-specific toxicity depended on the pH of the incubation system and was inversely proportional to chemical half-life. The toxicity of these agents is most likely due to the arenediazonium cation which is a relatively stable intermediate. In a sublethal concentration range most triazeness induced significant increases of SCE rates. These are interpreted as an indirect consequence of cytotoxicity. Upon metabolic activation, the compounds were genotoxic in a dose-dependent fashion. Their SCE-inducing capacity depended on the nature of the alkylating species generated, i.e., the alkyldiazonium cation, and on chemical stability. Surprisingly, no deuterium isotope effect was observed in DMPT-d6. The order of genotoxic activity among the aryldialkyltriazenes was DMpNPT much greater than DMPT = DMPT-ds greater than DMpMPT much greater than DEPT greater than DnPrPT greater than or equal to DiPrPT. DPMT was a marginal SCE inducer but very toxic upon metabolic activation. As monooxygenation of DPMT, like spontaneous hydrolysis, should generate a phenyldiazonium cation, the results suggest that arylation of DNA causes a very low SCE induction, if any.

Animals↗
PubMed1975

[The use of combined spectroscopy in analytical toxicology (author's transl)].

The combined application of the four spectrometric techniques UV, IR, NMR and MS is an important analytical tool for the identification of the increasing number of potential poisons with which the analysts in the fields of forensic sciences and toxicology are confronted. Some of the contributions of these techniques to toxicological analyses are reviewed and illustrated by a few examples. Furthermore, the incorporation of the four methods into the analytical scheme, the requirements with respect to quantity and purity of the unkown substances, as well as the different possibilities for the combination of separation and identification techniques are outlined.

Magnetic Resonance Spectroscopy↗
PubMed1977

[Investigations of carbromal metabolism (author's transl)].

Erythro-2-Brom-2-ethyl-3-hydroxybutyramide has been isolated from the urines of patients with Carbromal intoxications as well as from the urine of rat, mouse and dog treated with either Carbromal or with 2-Brom-2-ethyl-acetamide. The identification of the excreted and synthetized metabolite was carried out by means of IR, Mass and NMR spectroscopy. Along with the erythro-2-Brom-2-ethyl-3-hydroxybutyramide one other bromine containing compound was isolated after Carbromal application only, its mass spectrum and rel. RF values having the same characteristics as the synthetized erythro-2-Brom-2-ethyl-3-hydroxybutyrylcarbamide. However, the purification of this metabolite so far has not been successful.

Animals↗
PubMed1975

Two unusual barbiturate deaths.

The case histories and toxicological examination of two unusual fatal barbiturate poisonings are presented. One case involved the suicidal ingestion of a veterinarian euthanasia preparation containing pentobarbital which resulted in extremely high concentrations of the drug in the blood and liver. The second case involved the suicidal ingestion of vinbarbital, a drug no longer available on the american pharmaceutical market. The case exemplifies the necessity for definitive and analytical procedures for the identification of drugs in biological samples. Identification of pentobarbital and vinbarbital was by infrared spectrophotometry and thin layer chromatography. Quantitation of these drugs was by ultraviolet spectrophotometry.

Aged↗
PubMed1976

Cell-wall composition and taxonomy of Cephaloascus fragrans and some Ophiostomataceae.

Carbohydrates of intact cells and cell walls were studied by gas-liquid chromatographical analysis after acid hydrolysis. Isolated cellulose was determined by infrared spectrophotometry, pyrolysis mass spectrometry and histochemistry. Biochemical characters do not support an assumed relationship between Ophiostoma (including Europhium) and Cephaloascus fragrans. Cephaloascus fragrans differs from Ophiostoma by a high mannose content and by the absence of cellulose and rhamnose. A relationship between Cephaloascus fragrans and Ceratocystis cannot be excluded on the basis of the biochemical characters, although there is a marked difference in conidiogenesis. Saprolegnia ferax (Oomycetes) was included as a cellulose-containing fungus for comparison.

Ascomycota↗