Neste trabalho foi desenvolvido um método usando a microextração em fase sólida (SPME) para análise cromatográfica em fase gasosa capilar com detector de ionização por chama (CG/ IC) de orto-cresol urinário, metabólito do tolueno. Após otimização das variáveis da SPME e da validação do método, foram analisadas amostras de urina de 27 trabalhadores expostos a solventes em oficinas de reparo auto...

A biofilm of Arthrobacter viscosus supported on granular activated carbon was used to remove chromium and organic compounds (chlorophenol, phenol and o-cresol) from aqueous solutions. The compounds were studied as single solutes and in different combinations between them and Cr(VI). Optimum Cr(VI) adsorption was observed at a phenol concentration of 100 mg/l and at an initial concentration of t...

The distribution coefficients for phenols (phenol, o-cresol, m-cresol, p-cresol, 3,5-xylenol and α-naphthol) in ionic liquid (1-butyl-3-methylimidazolium haxafluorophosphate ([bmim][PF6]))/water two-phase system were measured at 298 K to examine a removal ability of phenols in wastewater by the liquid-liquid extraction. Judging from these distribution coefficients, it is feasible that phenols c...

Acid-base titrations can be carried out successfully in the solvent ??Icresol’. This is important for the determination of the acid or base content of some polymers for which ~cresol is a good solvent. The study of acid-base coulometry in nr-cresol was started because of the several advantages offered by coulometry: greater sensitivity, no problems with unstable titrants, and no need for standa...

Hybrid inorganic/organic adsorbents were synthesized using mixtures of diatomite and carbon charcoal as precursors, and explored for the removal of p-cresol from aqueous solution. The carbon/diatomite composites displayed a bimodal and interconnected porous structure which was partially inherited from both precursors. They display moderate surface areas (between 100 and 400 m(2)g(-1)) due to th...

A sensitive and reproducible gas chromatographic procedure for the quantitative determination of urinary o-cresol is described. The first step involves acid hydrolysis (2N HCl, 100 degrees C, 10 min), which yields unconjugated o-cresol. After extraction (methylene chloride, pH 2), the organic layer is concentrated by evaporation and samples are analyzed by gas chromatography-flame ionization de...

The kinetics of the oxidation of p-cresol by Compound II of horseradish peroxidase has been studied by the stopped flow technique at an ionic strength of 0.11 from pH 2 to 11. In acid solution the reaction is kinetically first order in jcresol, but in the alkaline region a saturation effect attributable to complex formation is observed. At very high pH an additional second order reaction betwee...

The herbicide 4,6-dinitro-o-cresol inhibits electron transport to ferricyanide and non-cyclic photophosphorylation for 50% at about 15 /am. At higher concentrations the photosystem I depen­ dent M ehler reaction ascorbate/dichlorophenolindophenol to methyl viologen is stimulated, while cyclic photophosphorylation is inhibited. The herbicide thus is an inhibitory uncoupler. Although the chemical...

Aminonitrotoluenes form rapidly from the reduction of dinitrotoluenes (DNTs) which are priority pollutants and animal carcinogens. For example, 4-amino-2-nitrotoluene (4A2NT) and 2A4NT accumulate from the reduction of 2,4-DNT during its aerobic biodegradation. Here, we show that 2,4-DNT dioxygenase (DDO) from Burkholderia sp. strain DNT oxidizes the aminonitrotoluenes 2A3NT, 2A6NT, 4A3NT, and 5...

Pre- and/or probiotics can cause changes in the ecological balance of intestinal microbiota and hence influence microbial metabolic activities. In the present study, the influence of oligofructose-enriched inulin (OF-IN), Lactobacillus casei Shirota, and Bifidobacterium breve Yakult on the colonic fate of NH3 and p-cresol was investigated. A randomized, placebo-controlled, crossover study was p...