Polycyclic aromatic hydrocarbons from wood pyrolyis in charcoal production furnaces

Polycyclic aromatic hydrocarbons (PAH) were measured in smoke samples from wood carbonization during charcoal production, in both particulate matter (PM) and gaseous phases. Samples were acquired using a medium-volume air sampler at 1.5 m distance from the furnace. Particle-bound PAH were collected on Fluoropore polytetrafluoroethylene filters and gas-phase PAH were collected into sorbent tubes with XAD-2 resin. PAH were extracted with dichloromethane-methanol and analyzed using gas chromatography-mass spectrometry. The results showed total emission from the furnace of 26 mu g/m(3) for the 16 PAH and 2.8 mu g/m(3) for the 10 genotoxic PAH (from fluoranthene to benzo[g,h,i]perylene). High emission of 16 PAH in the first 8 h of wood carbonization was detected (64 mu g/m(3); 56% of the total emission). Associated with PM, 11% of the total emission of 16 PAH (in both phases) and 60% of 10 genotoxic PAH were found. Relative ratios (for example, [Phe]/[Phe] + [Ant]) for the PAH of the same molecular weight were obtained and compared with the published data. The concentrations of benzo[a]pyrene equivalent (BaPeq) were estimated using the list of toxic equivalent factors suggested by Nisbet and LaGoy, 1992. The values of 0.30 and 0.06 mg/m3 were obtained for the total concentrations of BaPeq in PM and gaseous phase, respectively. (c) 2006 Elsevier B.V. All rights reserved.

Identification of polycyclic aromatic hydrocarbons and methoxylated phenols in wood smoke emitted during production of charcoal

More than 130 organic substances in dichloromethane-methanol (4: 1) extracts of particulate matter and the gaseous phase from wood burning for the production of charcoal have been identified by capillary gas chromatography coupled with low-resolution mass spectrometry (GC-MS), use of GC retention indices, and comparison with authentic standards. Many of the substances identified are methoxyphenols (derivatives of syringol and guaiacol), polycyclic aromatic hydrocarbons (PAH), oxidized PAH (oxy-PAH), and levoglucosan, the last being a monosoccharide derivative from the thermal breakdown of cellulose. The amount of unsubstituted PAH was greater than that of methyl- and dimethyl-substituted homologs.

Polycyclic aromatic hydrocarbons and other selected organic compounds in ambient air of Campo Grande City, Brazil

Fourteen samples of particulate matter and semi-volatile organic compounds were collected during 6 months in the city of Campo Grande, South Mato Grosso State, Brazil. Particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected on Fluoropore PTFE filters and gas-phase PAHs were collected into sorbent tubes with XAD-2 resin. Both types of samples were extracted with a dichloromethane/methanol mixture (4:1 v/v), then the extracts were subjected to gas chromatography-mass spectrometry (GC-MS) analysis. PAHs, oxidized PAH (oxy-PAHs), phenols and methoxyphenols were identified by use of GC retention indices and MS files. The average value obtained for the sum of 15 PAHs was 21.05 ng m(-3) (range: 8.94-62.5 ng m(-3)). The presence of specific tracers and calculations of characteristic ratios (e.g. [Phe]/[Phe] + [Ant]) were used to identify the sources of the emissions of PAHs in the atmospheric samples. Levoglucosan (the anhydride of beta-glucose), retene (1-methyl-7-isopropylphenanthrene) and methoxyphenols (derivatives of syringol and guaiacol) and tracers for wood burning were identified. This study demonstrates that biomass burning from the rural zone is the main source of PAHs and emissions of other substances in the investigated site of Campo Grande. (c) 2004 Elsevier Ltd. All rights reserved.

Electrochemical reduction of aromatic sulfinic acids in dimethylsulfoxide

The electrochemical reduction of benzenesulfinic, p-toluenesulfinic, and p-nitrobenzenesulfinic acids was studied in dimethylsulfoxide solutions. From cyclic voltammetry experiments, a chemical reaction following the first electron transfer was detected during the reduction process. A cyclic voltammetry technique using ultramicroelectrodes has provided kinetic parameters for the electron-transfer steps, from which it was possible to observe the influence of the ring substituent on the electrochemical reduction. The mechanism of the electroreduction of aromatic sulfinic acids in dimethylsulfoxide depends upon the nucleophilic attack of the radical anion produced on the starting compound during the reduction processes.

Biocompatibility of gutta-percha solvents using in vitro mammalian test-system

Objectives. Taking into consideration that DNA damage and cellular death play important roles during carcinogenesis, the purpose of the present study was to evaluate in vitro genotoxic or cytotoxic effects of chloroform and eucalyptol by single cell gel (comet) assay and trypan blue exclusion test, respectively.Study design. Chloroform and eucalyptol were exposed to Chinese hamster ovary cells in culture directly for 3 hours at 37 degrees C at final concentrations ranging from 1.25 to 10 mu L/mL. The negative control group was treated with vehicle control (phosphate-buffered solution), and the positive control group was treated with methyl metasulfonate (MMS, at 1 mu g/mL concentration). All data were analyzed by the Kruskal-Wallis nonparametric test followed by the Dunn test.Results. The results showed that both gutta-percha solvents were cytotoxic at concentrations of 2.5, 5, and 10 mu L/mL (P < .05). on the other hand, both solvents did not induce DNA breakage at 1.25 mu L/mL concentration.Conclusions. These results suggest that both chloroform or eucalyptol are strong cytotoxicants, but they may not be a factor that increases the level of DNA lesions in mammalian cells.

Identification of polycyclic aromatic hydrocarbons in sugar cane soot by gas chromatography mass spectrometry

Fly soot samples collected in the sugar cane fields after the process of burning were extracted in a Soxhlet apparatus (methylene chloride:methanol 4:1). The extracts were fractionated on silica gel Sep-Pak cartridges into three fractions. A gas chromatographic-mass spectrometric study of the fly soot extracts allowed the identification of the PAH with mutagenic and carcinogenic properties. Large amounts of aliphatic hydrocarbons, fatty acid esters and some PAHs were identified by GCMS in full scan mode. GC-MS in the selective ion monitoring mode (SIM) was suitable for the determination of many PAHs, which are often present in the burnt biomass. 31 PAHs and 7 thiophens derivatives were identified. The presence of these compounds should be regarded as a caution to workers and the general population to avoid exposure to the fly soot.

Aromatic compounds produced by Periconia atropurpurea, an endophytic fungus associated with Xylopia aromatica

6,8-Dimethoxy-3-(2'-oxo-propyl)-coumarin (1) and 2,4-dihydroxy-6-[(1'E,3'E)-penta-1', 3'-dienyl]-benzaldehyde (2), in addition to the known compound periconicin B (3), were isolated from the ethyl acetate extract of Periconia atropurpurea, an endophytic fungus obtained from the leaves of Xylopia aromatica, a native plant of the Brazilian Cerrado. Their chemical structures were assigned based on analyses of MS, 1D and 2D-NMR spectroscopic experiments. Biological analyses were performed using two mammalian cell lines, human cervix carcinoma (HeLa) and Chinese hamster ovary (CHO). The results showed that compound I had no effect when compared to the control group, which was treated with the vehicle (DMSO). Compound 2 was able to induce a slight increase in cell proliferation of HeLa (37% of increase) and CHO (38% of increase) cell lines. Analysis of compound 3 showed that it has potent cytotoxic activity against both cell lines, with an IC50 of 8.0 mu M. Biological analyses using the phytopathogenic fungi Cladosporium sphaerospermum and C. cladosporioides revealed that also 2 showed potent antifungal activity compared to nystatin. (c) 2006 Elsevier Ltd. All rights reserved.

Analysis of aromatic amines in surface waters receiving wastewater from a textile industry by liquid chromatographic with electrochemical detection

A high performance liquid chromatography ( HPLC) method with electrochemical detection (ED) was developed for the determination of benzidine, 3,3-dimethylbenzidine, o-toluidine and 3,3-dichlorobenzidine in the wastewater of the textile industry. The aromatic amines were eluted on a reversed phase column Shimadzu Shimpack C-18 using acetonitrile + ammonium acetate (1 x 10(-4) mol L-1) at a ratio 46: 54 v/v as mobile phase, pumped at a flow rate of 1.0 mL min(-1). The electrochemical oxidation of the aromatic amines exhibits well-defined peaks at a potential range of +0.45 to +0.78 V on a glassy carbon electrode. Optimum working potentials for amperometric detection were from 0.70 V to +1.0 V vs. Ag/AgCl. Analytical curves for all the aromatic amines studied using the best experimental conditions present linear relationship from 1 x 10(-8) mol L-1 to 1.5 x 10(-5) mol L-1, r = 0.99965, n = 15. Detection limits of 4.5 nM (benzidine), 1.94 nM (o-toluidine), 7.69 nM (3,3-dimethylbenzidine), and 5.15 nM (3,3-dichlorobenzidine) were achieved, respectively. The detection limits were around 10 times lower than that verified for HPLC with ultra violet detection. The applicability of the method was demonstrated by the determination of benzidine in wastewater from the textile industry dealing with an azo dye processing plant.

Fast chromatographic determination of polycyclic aromatic hydrocarbons in aerosol samples from sugar cane burning

Sugar cane burning in Brazil causes remarkable amounts of organic compounds to be emitted amongst which the polycyclic aromatic hydrocarbons (PAHs) represent serious health hazards. Therefore, 24-h aerosol samples (< 10 mum aerodynamic diameter) were collected in Araraquara city (São Paulo state) during the harvest season using a Hi-Vol sampler. PAHs were recovered using an Accelerated Solvent Extractor and analyzed by low-pressure gas chromatography-ion trap mass spectrometry (LP-GC-IT-MS). The fully automated extraction process was performed in less than 25 min with a solvent consumption of approximately 20 ml. The use of a deactivated 0.6 m x 0. 10 mm i.d. restrictor coupled to a 10 m wide-bore analytical column allowed most of the 16 PAHs in EPA's priority list to be identified and quantified in only 13 min. Concentrations of PAHs in Nraraquara aerosols ranged between 0.5 and 8.6 ng m(-3). (C) 2003 Elsevier B.V. All rights reserved.

Dipole moments in Langmuir monolayers from aromatic carboxylic acids

The three-layer capacitor model proposed by Demchak and Fort [J. Colloid Interface Sci. 46 (1974) 191] is employed to relate measured surface potentials of Langmuir monolayers from a series of polyphenyl carboxylic acids to molecular dipole moments calculated using semiempirical quantum methods. The effective dielectric constant at the air/monolayer interface is 3.0 +/- 0.6, very close to that estimated for aliphatic compounds. Good agreement between theory and experiment is obtained by adopting a dielectric constant of 6.4 for the monolayer/water interface and a contribution from the water reorientation of -0.064 +/- 0.006 D, which shows that the parameters in the DF model are essentially the same as for aliphatic amphiphiles, such as esters, acids, alcohols and ethers. (C) 2000 Elsevier B.V. B.V. All rights reserved.

MEH-PPV hypsochromic shifts in halogenated solvents induced by gamma-rays

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aromatic antiepileptic drugs and mitochondrial toxicity: Effects on mitochondria isolated from rat liver

Idiosyncratic hepatotoxicity is a well-known complication associated with aromatic antiepileptic drugs (AAED), and it has been suggested to occur due to the accumulation of toxic arene oxide metabolites. Although there is clear evidence of the participation of an immune process, a direct toxic effect involving mitochondria dysfunction is also possible. The effects of AAED on mitochondrial function have not been studied yet. Therefore, we investigated, in vitro, the cytotoxic mechanism of carbamazepine (CB), phenytoin (PT) and phenobarbital (PB), unaltered and bioactivated, in the hepatic mitochondrial function. The murine hepatic microsomal system was used to produce the anticonvulsant metabolites. All the bioactivated drugs (CB-B, PB-B, PT-B) affected mitochondrial function causing decrease in state three respiration, RCR, ATP synthesis and membrane potential, increase in state four respiration as well as impairment of Ca(2+) uptake/release and inhibition of calcium-induced swelling. As an unaltered drug, only PB, was able to affect mitochondrial respiration (except state four respiration) ATP synthesis and membrane potential; however, Ca(2+) uptake/release as well as swelling induction were not affected. The potential to induce mitochondrial dysfunction was PT-B > PB-B > CB-B > PB. Results suggest the involvement of mitochondrial toxicity in the pathogenesis of AAED-induced hepatotoxicity. (C) 2008 Elsevier Ltd. All rights reserved.

Influence of different solvents on the structural, optical and morphological properties of CdS nanoparticles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Improving the Fluorescence Detectability of Polycyclic Aromatic Hydrocarbons for Evaluation of Workplace Environments of Cement Industries Processing Organic Residues

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Extracellular tannase from Emericella nidulans showing hypertolerance to temperature and organic solvents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)