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The seaweed Asparagopsis armata has been shown to be a successful intervention to mitigate methane (CH 4) emissions from ruminants due to the content of halogenated components, including bromoform. Some groups have been exploring extracting or synthesizing bromoform to be used as a feed additive rather than using whole seaweed biomass. This study was conducted to understand the differences between whole A. armata biomass and bromoform in their ability to reduce CH 4 production when included in ruminant diets. A series of in vitro experiments were conducted, with a control group consisting of a 50 % hay:50 % concentrate. A. armata biomass supplementation levels of 0.25 and 0.50 %, containing 0.0037 and 0.0077 mg bromoform on a dry matter (DM) basis, respectively, were evaluated. Bromoform was evaluated at 0.0018, 0.0036, and 0.0073 mg. The two highest levels of bromoform were comparable to the bromoform content in the seaweed biomass. Adding A. armata biomass led to significant reductions in CH 4 yield (mL/g) of 62.5 and 95.6 %, respectively, without compromising in vitro fermentation characteristics. The addition of bromoform resulted in a decrease in the CH 4 yield (mL/g) by 7.6, 23.0, and 59.6 %, respectively. In conclusion, while bromoform led to a dose-dependent reduction in CH 4 production, A. armata has a greater effect at equivalent doses of bromoform, suggesting that the other components in the biomass, which were responsible for up to 40 % of the reduction, play a significant role in the anti-methanogenic efficiency of A. armata. • This study evaluated the differences in the anti-methanogenic potential of Asparagopsis armata biomass versus bromoform. • While bromoform was the strongest anti-methanogenic compound, the biomass was 36-40 % more powerful than bromoform alone. • At the tested levels, the biomass and bromoform had no negative impacts on in vitro rumen fermentation. • The role of bioactive compounds other than bromoform in Asparagopsis biomass is significant and should not be ignored. [ABSTRACT FROM AUTHOR]

Several invasive species can occupy the same geographic area. Interaction between species depends on several factors, and the results of such interactions can be highly diverse. Asparagopsis armata is a invasive red seaweed whose exudates contain a cocktail of toxic halogenated compounds. In this study, the impact of high and low levels of A. armata on the bivalve Ruditapes philippinarum was assessed in a laboratory experiment. Both are prominent invasive species in Europe and could share the same habitats. The effects of the algae were measured at different biological levels, framed by an integrated approach: bioturbation as a proxy for organismal activity and behaviour within the sediment, and several subcellular biomarkers related to oxidative stress and damage, energy metabolism, detoxification, and neurotransmission. While bioturbation revealed the effects of exudates on the bivalve, with a decrease in most parameters when exposed to the different amounts of algae, only marginal responses were found for biomarkers, suggesting a possible temporal decoupling between the behavioural response and the intrinsic biochemical environment. These results denote that despite the recognized potential of biomarkers to address a myriad of situations, a proxy for higher levels of biological organization, such as behaviour, for its integration of lower-level effects, is a robust tool to address complex and lesser-known mixtures of stressors. [Display omitted] • The results of interactions between invasive species can be highly diverse. • The impact of A. armata on the bivalve R. philippinarum was assessed. • An integrated approach was used to assess the effects of the algae. • Bioturbation response was evident, while biomarkers had only marginal responses. • Temporal decoupling between behaviour and the intrinsic biochemical responses. [ABSTRACT FROM AUTHOR]

[Display omitted] • The molecular structures of the neutral and cation 1,2-dichloropropane (C 3 H 6 Cl 2) have been studied. • Three stable conformations have been found for the isolated neutral molecule. • Five stable conformations have been found for the isolated molecular cation. • First ionization energy and IR spectra were calculated and compared to experimental data. A theoretical investigation on the molecular structures of the isolated 1,2-dichloropropane (C 3 H 6 Cl 2) neutral and its molecular cation was performed using high levels of density functional theory and ab initio methods. Three stable structural conformers have been found for the neutral molecule, with the Trans conformation being the most stable by about 5.8 kJ/mol on average in comparison with the (+) Gauche and (−) Gauche conformations. As for the molecular cation, five stable conformational structures have been determined with energy differences within about 25 kJ/mol, and with the (−) Near Cis conformer being the most stable cation species. The computed vibrational frequencies were compared with experimental values and the main IR spectral features assigned. The theoretical first adiabatic ionization energy of has been determined as 10.69 ± 0.05 eV, from the corresponding neutral and cation molecular energies, via ab initio composite methods, and is in good agreement with the experimental value from photoelectron spectroscopy. [ABSTRACT FROM AUTHOR]

[Display omitted] • A general, selective, and sensitive probe for volatile halogenated carbonyl compounds. • The detection limit of the fluorescent probe was at the nM level. • Application of the probe in the efficient determination of yields for organic reactions. • Mechanism studies revealed a non-bonding interaction of analyst and probe. The fluorescent detection of neutral and volatile carbonyl halogenated compounds had not been studied before. We describe here a simple and sensitive turn-on rhodamin fluorescent probe for the selective detection of fluorinated/brominated/chlorinated/iodinated carbonyl compounds. A wide range of linear or cyclic volatile organic halides was detected with a limit of detection as low as 45.6 nM within 1 min. Mechanistic experiments and DFT calculations indicate the reversible formation of a 1:1 complex of sensor and analyst through non-bonding interaction. [ABSTRACT FROM AUTHOR]

• Key volatile pollutants in the gaseous emissions of MSW were assessed. • Ethanol, methyl mercaptan and H 2 S were key pollutants during airtight storage stage. • DMDS, 1,2-dichloroethane and trichloroethylene were key pollutants during ventilation. Gaseous emissions from municipal solid waste (MSW) have raised many concerns and complaints. Identifying the key volatile pollutants in the complex gaseous emissions from MSW is significant for the efficient mitigation of their odor nuisances and health risks. For this purpose, we present an integrated investigation of the key volatile pollutants in the gaseous emissions of MSW from the perspectives of emission patterns, odor concentrations and health risks. Air samples were collected during four different emission stages of the waste matrix for both chemical and olfactometric analyses. The total chemical concentrations of the volatile compounds in the air samples were in the range of 21.49 mg m−3 to 295.61 mg m−3, and the odor concentrations varied from 1122 ou E m−3 to 17,782 ou E m−3. The odor concentrations in the air samples were well correlated with the odor activity values (OAV s) of sulfur compounds, oxygenated compounds and ammonia (r = 0.922, 0.879 and 0.780, respectively, for n = 17 and p < 0.01). Moreover, from an integrated perspective involving chemical emissions, the proportions of odor concentrations and health risks, ethanol, methyl mercaptan and hydrogen sulfide were identified as the key volatile pollutants in the gaseous emissions from the waste matrix during the airtight storage stage, and dimethyl disulfide, 1,2-dichloroethane and trichloroethylene were the key volatile pollutants during the ventilation stage. [ABSTRACT FROM AUTHOR]

This study put a great emphasis on the role of carbon dioxide (CO 2 ) in thermal decomposition of polyvinyl chloride (PVC). To do this, systematic experimental works were carried out to explore the influence of CO 2 on pyrolysis of PVC by comparing with that in N 2 . First of all, a series of thermo-gravimetric analysis (TGA) of PVC in N 2 and CO 2 was performed to characterize the thermal deconstruction of PVC in N 2 and CO 2 , which confirmed that any physical aspect ( i.e. , onset and end temperature of depolymerization of PVC) attributed by CO 2 was nearly negligible as compared to the case in N 2 . This phenomenon was also fully evidenced by differential thermogram (DTG) and differential scanning calorimeter (DSC) because both DTG and DSC curves in N 2 and CO 2 were identical. However, the concentration profiles of CO evolved from the thermal degradation of PVC in N 2 and CO 2 was significantly different: the enhanced generation of CO occurred in the presence of CO 2 . This observation suggested that the genuine role of CO 2 is to consume carbon source ( i.e. , acting as a carbon scavenger) for pyrolysis of PVC. It also provided a favorable condition for suppressing the formation of harmful chemical compounds such as benzene derivatives and polycyclic aromatic hydrocarbons (PAHs). Therefore, the mass portion of the oil in pyrolytic products produced from pyrolysis of PVC in CO 2 was lower than that in N 2 . These particular thermal degradation behaviors may be explained by the genuine role of CO 2 : the enhanced thermal cracking of volatile organic carbons (VOCs) evolved from the pyrolysis of PVC. The findings of this study strongly suggest that CO 2 can be effectively applied to thermal disposal of recalcitrant wastes since employing CO 2 in thermal treatment provides a means for in-situ mitigation and/or reduction of harmful chemical species. [ABSTRACT FROM AUTHOR]

Highlights: [•] Organohalogens and total mercury were measured in prey fish of thick-billed murres. [•] No one fish species had the highest levels across all contaminant groups. [•] Biomagnification from fish to thick-billed murre was highest for Σ21PCB and ΣDDT. [•] Major contaminants were consistently higher in Arctic cod than in capelin. [Copyright &y& Elsevier]

Abstract: An exhaustive characterization of the biogas from some waste disposal facilities has been carried out. The analysis includes the main components (methane, carbon dioxide, nitrogen and oxygen) as well as trace components such as hydrogen sulphide, ammonia and VOCs (volatile organic compounds) including siloxanes and halogenated compounds. VOCs were measured by GC/MS (Gas Chromatography/Mass Spectrometry) using two different procedures: thermal desorption of the Tenax TA and Carbotrap 349 tubes and SPME (Solid Phase Micro-Extraction). A method has been established to measure the total halogen content of the biogas with the AOX (adsorbable organically bound halogens) technique. The equipment used to analyze the samples was a Total Organic Halogen Analyzer (TOX-100). Similar results were obtained when comparing the TOX (Total Organic Halogen) values with those obtained by GC/MS. The halogen content in all the samples was under 22 mg Cl/Nm3 which is below the limit of 150 mg/Nm3 proposed in the Spanish Regulations for any use of the biogas. The low chlorine content in the biogas studied, as well as the low content of other trace compounds, makes it suitable for use as a fuel for electricity generating engines. [Copyright &y& Elsevier]

Abstract: Accumulation of organochlorine compounds is well studied in aquatic food chains whereas little information is available from terrestrial food chains. This study presents data of organochlorine levels in tissue and plasma samples of 15 critically endangered Iberian lynx (Lynx pardinus) and other 55 wild carnivores belonging to five species from three natural areas of Spain (Doñana National Park, Sierra Morena and Lozoya River) and explores their relationship with species diet. The Iberian lynx, with a diet based on the consumption of rabbit, had lower PCB levels (geometric means, plasma: <0.01ngmL−1, liver: 0.4ngg−1 wet weight, fat: 87ngg−1 lipid weight) than other carnivores with more anthropic and opportunistic foraging behavior, such as the red fox (Vulpes vulpes; plasma: 1.11ngmL−1, liver: 459ngg−1, fat: 1984ngg−1), or with diets including reptiles at higher proportion, such as the Egyptian mongoose (Herpestes ichneumon; plasma: 7.15ngmL−1, liver: 216ngg−1, fat: 540ngg−1), or the common genet (Genetta genetta; liver: 466ngg−1, fat: 3854ngg−1). Chlorinated pesticides showed interspecific variations similar to PCBs. Organochlorine levels have declined since the 80s in carnivores from Doñana National Park, but PCB levels are still of concern in Eurasian otters (Lutra lutra; liver: 3873–5426ngg−1) from the industrialized region of Madrid. [Copyright &y& Elsevier]

Abstract: Stationary phase selectivities for halogenated compounds in reversed-phase HPLC were compared using C18 monolithic silica capillary columns modified with poly(octadecyl methacrylate) (ODM) and octadecyl moieties (ODS). The preferential retention of halogenated benzenes on ODM was observed in methanol/water and acetonitrile/water mobile phases. In selectivity comparison of selected analytes on ODM and ODS, greater selectivities for halogenated compounds were obtained with respect to alkylbenzenes on an ODM column, while similar selectivities were observed with a homologous series of alkylbenzenes on ODM and ODS columns. These data can be explained by greater dispersive interactions by more densely packed octadecyl groups on the ODM polymer coated column together with the contribution of carbonyl groups in ODM side chains. For the positional isomeric separation of dihalogenated benzenes (ortho-, meta-, para-), the ODM column also provided better separation of these isomers for the adjacently eluted isomers that cannot be completely separated on an ODS column in the same mobile phase. These results imply that the ODM column can be used as a better alternative to the ODS column for the separation of other halogenated compounds. [Copyright &y& Elsevier]

In this study, photo/oxidation/reduction degradability of Ocuflox (OFX) antibiotic by UV/ZnO/sulfite (UZS) and UV-C/ZnO/KI (UZI) processes was evaluated. The slight amount of OFX degradation by UV / ZnO (UZ) and UV alone was observed after 5 min. The best performance for UZS and UZI processes was observed in the alkaline pH; although, the complete OFX degradation by UZS and UZI was achieved after 5 and 30 min of reaction (81.4% of OFX degradation by UZI was achieved after 5 min). The obtained results from kinetic studies proved this phenomenon, as the r obs (mg L−1 min) values for UV alone, UZ, UZI and UZS, were calculated 0.028 mg L−1 min, 0.07 mg L−1 min, 0.56 mg L−1 min and 0.7 mg L−1 min, respectively. In addition the energy consumption and total cost values for system was significantly decreased when sulfite and iodide and sulfite were entered in the photo-catalyst system environment. The scavenging studies indicated both e aq - (generated by reductant agent) and •OH radicals (generated by oxidant agent) have a great importance in the degradation of OFX. In addition, in the final product produced by these processes (UZI and UZS), the degradation of the OFX aromatic compound into linear compounds with high ability in mineralization was demonstrated. Therefore, photo-oxidation-reduction processes due to low time and cost required for degradation of OFX and also high degradation ability of OFX can were applied to degrade the similar pollutants. [Display omitted] • The significant degradation of OFX in the presence of sulfite and KI reductant agents in the photocatalytic reaction environment was observed. • The lower E EO and TCS values proved economically superiority of the UV/ZnO process in the presence of sulfite and KI. • It was proved e aq - and •OH radicals have the significant role in the degradation of OFX by UV/ZnO process in the presence of sulfite and KI. [ABSTRACT FROM AUTHOR]

Peroxidase transformations of widely distributed pollutants, tetra- and penta-chlorinated phenols and anilines, were studied using different peroxidases. Chloroperoxidase from Caldariomyces fumago was able to transform tetra- and penta-chlorinated phenols and anilines, while horseradish peroxidase, lignin peroxidase from Phanerochaete chrysosporium and versatile peroxidase from Bjerkandera adusta were able only to transform the halogenated phenols. Chloroperoxidase showed a specific activity on pentachlorophenol two orders of magnitude higher than lignin peroxidase and horseradish peroxidase, and one order of magnitude higher than versatile peroxidase. The main product from peroxidase oxidation in all cases was a polymeric and insoluble material. The insolubilization of halogenated phenols and anilines permits their removal, reduces their bioavailability, and thus reduces their environmental impact. The other minor products from the enzymatic transformation of highly chlorinated compounds were determined by mass spectrometry. Tetrachloroquinone, dimers and trimers of halogenated compounds were also identified. Chloroperoxidase was able to halogenate tetrachloroaniline to form pentachloroaniline. [Copyright &y& Elsevier]

Abstract: Corrosion of Hastelloy C-276, Titanium Gr2, and Zirconium 702 were investigated at subcritical and supercritical conditions using a continuous anticorrosive reactor. The morphology of each alloy surface changed after being exposed by oxidation of 2-chlorophenol in water. The depth of oxygen penetration in the metal exposed by supercritical conditions was generally deeper than that under subcritical conditions. On the other hand, there was a greater loss of alloys at the subcritical condition than at the supercritical condition. Metal oxides and cations from the alloy corrosion in the reactor increased the decomposition efficiency of 2-chlorophenol. The decomposition efficiency from the corrosion of Hastelloy C-276 and Zirconium 702 was slightly higher than that from the corrosion of Titanium Gr2. It can be concluded that Titanium Gr2 has the best corrosion resistance of the tested alloys because it showed the lowest mass loss and oxygen penetration. [Copyright &y& Elsevier]

The DRAG test is a rapid high-throughput screening assay for detection of repairable adducts by growth inhibition of Chinese hamster ovary cells (CHO) characterized by different defects in DNA repair. A more pronounced growth inhibition caused by a certain DNA-reactive substance in a repair-deficient cell line (EM9, UV4 and UV5) as compared to wild-type cells (AA8) is interpreted as a consequence of their inability to repair induced DNA lesions. Thus, the use of such cell lines in the DRAG test may provide information of the type of DNA lesions induced by a certain genotoxic substance.To select optimal assay conditions, as well as to provide a mechanistic basis for interpreting the results, the model compounds benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), ethyl methanesulfonate (EMS), mitomycin C (MMC) and hydrogen peroxide (H2O2) were used. These agents can induce bulky adducts, alkyl adducts, cross-links and oxidative damage, respectively.The specificity of the DRAG test constitutes an important prerequisite for its practical use in a broader context. To assess this aspect, we have investigated the genotoxic and cytotoxic properties of a selection of metabolites of and isomers from polychlorinated biphenyls (PCB) and polybrominated diphenyl ethers (PBDE), along with a few other halogenated compounds. All these compounds have been detected as pollutants in the external environment, and for most of them there is no convincing evidence of mutagenicity from conventional assays.As could be predicted from their mode of action, BPDE, MMC, and EMS were all found to be more toxic in the repair-deficient cell lines compared with wild-type cells. The results with H2O2 were inconclusive, and the PCB metabolite 4,4′-diOH-CB80 only exhibited borderline activity, while all other halogenated compounds, or their metabolites, were found to be inactive.In conclusion, the DRAG assay could provide a robust and useful tool when screening large numbers of potentially genotoxic agents, while in addition providing mechanistic information. However, the usefulness of the selected cell lines to detect oxidative damage may be limited. [Copyright &y& Elsevier]

A highly sensitive gradient microbore ion chromatographic method was developed with electrolytically generated hydroxide eluents for the determination of low μg/L levels of chloroacetate, bromoacetate, trifluoroacetate, dichloroacetate, chlorodifluoroacetate, dibromoacetate, trichloroacetate, bromodichloroacetate and dibromochloroacetate disinfectant by-products formed as a result of chlorination of drinking waters. The possibility of using a packed bed Dionex Atlas suppressor with a hydroxide gradient at microbore flow rates was investigated in order to reduce baseline noise levels. The Atlas suppressor displayed a very significant reduction in noise levels compared to the standard alternative ASRS Ultra suppressor, reducing noise by a factor of 15–20 in some cases, allowing trace haloacetic acids (HAs) to be seen with the direct injection of 100μL of treated water, with prior chloride and sulfate removal. To lower detection limits even further, a solid phase extraction was employed to preconcentrate HAs, resulting in detection limits of between 0.09 and 21.5μg/L. The method was applied to the determination of HAs in environmental samples and standard addition curves for three drinking water samples were carried out for both direct injection and preconcentration methods. R2 values in both cases were ≥0.98. Combined content for US Environmental Protection Agency regulated HAs in the three drinking water samples from Dublin City University; New Ross, Co. Wexford and Drogheda, Co. Louth were 46.5, 58.3 and 12.6μg/L, respectively. [Copyright &y& Elsevier]

Flammability limits measurement was made for a number of halogenated compounds by the ASHRAE method. Most of compounds measured are the ones for which discrepancy was noted between the literature values and predicted values of flammability limits. As a result, it has been found that most of the newly obtained values of flammability limits are not in accordance with the literature values. Numerical analysis was carried out for a set of flammability limits data including the newly obtained ones using a modified analytical method based on F-number scheme. In this method, fitting procedure was done directly to flammability limits themselves instead of fitting to F-number. After the fitting process, the average relative deviation between the observed and calculated values is 9.3% for the lower limits and 14.6% for the upper limits. [Copyright &y& Elsevier]

A new method for the determination of nine haloacetic acids (HAAs) with ion chromatography (IC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) was developed. With the very hydrophilic anion-exchange column and steep gradient of sodium hydroxide, the nine HAAs could be well separated in 15 min. After suppression with an ASRS suppressor that was introduced in between IC and ICP-MS, the background was much decreased, the interference caused by sodium ion present in eluent was removed, and the sensitivities of HAAs were greatly improved. The chlorinated and brominated HAAs could be detected as 35ClO and 79Br without interference of the matrix due to the elemental selective ICP-MS. The detection limits for mono-, di-, trichloroacetic acids were between 15.6 and 23.6 μg/l. For the other six bromine-containing HAAs, the detection limits were between 0.34 and 0.99 μg/l. With the pretreatment of OnGuard Ag cartridge to remove high concentration of chloride in sample, the developed method could be applied to the determination of HAAs in many drinking water matrices. [Copyright &y& Elsevier]

In order to reduce time of analysis, a new pressurized liquid extraction (PLE) method that automatically and rapidly achieves quantitative and selective extraction of 39 polybrominated diphenyl ether (PBDE) congeners in sediment samples was optimized. It consists of on-line cleanup by inclusion of sorbents in the extraction cell. The new method was compared with a conventional method based on the use of Soxhlet extraction followed by solid-phase extraction (SPE) with cartridges. The instrumental determination was performed by GC–MS, using negative chemical ionization in the selected-ion monitoring mode. Recoveries from 47 to 82% were obtained for spiked tri- to hepta-PBDE congeners in sediment sample. The repeatability of replicate extractions was better than 15% relative standard deviation. The detection limits obtained with the new developed method were between 1 and 46 pg/g dry weight. The reduction in the sample preparation (extraction + cleanup) time (from days to 30 min) with a similar efficiency than that afforded by the conventional Soxhlet extraction–SPE cleanup technique indicates the suitability of this method. The method was applied to sediment samples where the analytes were detected in the range of 0.86–2.49 ng/g dry mass. [Copyright &y& Elsevier]

An efficient method for the simultaneous determination of the degradation products of nonylphenol polyethoxylates (NPnEOs, n = number of ethoxy units), i.e., nonylphenol (NP), NPnEOs (n=1–3), nonylphenoxy carboxylic acids (NPnECs, n=1–2, number of ethoxy units plus an acetate) and their halogenated derivatives (XNP, XNP1EO and XNP1EC; X=Br or Cl), in water samples were developed. After trimethylsilylation with N,O-bis(trimethysilyl)acetamide, all the analytes were determined by gas chromatography–tandem mass spectrometry (GC–MS–MS) with electron ionization (EI). The ion peaks of [M−85]+ of the derivatives were selected as precursor ions and their product ions showing the highest intensities were used for the quantitative analysis. The instrumental detection limits were in the range from 2.1 to 11 pg. The recoveries of the analytes from the water samples were optimized by using solid-phase extraction (SPE). The deuterated reagents of octylphenol, octylphenol monoethoxylate and octylphenoxyacetic acid were used as the surrogates. The method detection limits (500 ml water sample) using C18 SPE were from 2.5 to 18 ng/l. The recoveries from spiked pure water and the environmental water samples were greater than 78%. The method was successfully applied to environmental samples. Remarkably, the concentrations of the halogenated compounds (ClNP, ClNP1EO and BrNP1EO) were detected at the hundreds of ng/l levels in the Neya river. [Copyright &y& Elsevier]

Aqueous capillary electrophoretic studies were performed to investigate interactions between halophenols and 1-ethyl-3-methylimidazolium tetrafluoroborate or tetraethylammonium tetrafluoroborate electrolytes. In both cases, increased halogen size correlated with increased affinity for the electrolyte cation. For isomers, the ortho substituted isomer exhibited higher affinity than the para isomer. Irreproducible CE results for analyte pairs in the presence of the ionic liquid stimulated investigations of the interactions between halophenols as well as with the cations of the electrolyte. These interactions were explored by proton and fluorine one-dimensional NMR. The NMR results indicated differences in the interactions between tetraethylammonium/iodophenols and imidazolium/iodophenols. The NMR results indicate hydrophobic stacking interactions between the iodophenols and possible similar interaction among phenols and imidazolium. [Copyright &y& Elsevier]

A strategy for determination of polybrominated diphenyl ethers, polychlorinated dibenzodioxins, polychlorinated dibenzofurans and polychlorinated biphenyls on fatty matrices has been established. After extraction, the proposed method allows the purification and the fractionation of all target groups of compounds in a simple multi-step automated clean-up. Furthermore, their subsequent analysis is carried out using a single benchtop mass spectrometer, in four separate injections. Required sensitivity considering levels found in the environment is attained using electron impact ionisation followed by tandem in time mass spectrometry. The whole method has been evaluated on standard solution and quality control samples consisting of fortified beef fat. Sensitivity, selectivity, accuracy and repeatability were tested with satisfactory results. [Copyright &y& Elsevier]

For the fast gas chromatographic identification of separated components the retention index is still one of the most often used tools, although mass spectrometry is available in almost all analytical laboratories. For the calculation of the retention indices it is not necessary to use n-alkanes or any other homologous series. If the analyte contains some compounds, not necessarily belonging to a homologous series, with well-known retention indices those compounds can be used as index references and the index of the other compounds can be calculated as is done using n-alkanes. The only difference is that instead of the carbon number of the n-alkanes, virtual carbon numbers of the reference compounds should be used. The method of calculation, and the effect of this method of calculation on the reproducibility are discussed in this paper, and analyses of some halogenated compounds and marjoram oil are used as experimental examples. [Copyright &y& Elsevier]

A method for the analysis of six alkyl organoiodides (iodomethane, iodoethane, 1-iodopropane, 1-iodobutane, 1-iodopentane, 1-iodohexane) commonly found in acetic acid process was developed. In this method the target analytes were determined by high-performance liquid chromatography (HPLC) using a post-column photochemical reactor with electrochemical detection (ED) in less than 30 min. HPLC was performed in ODS C18 reversed-phase column (5 μm, 250×4.6 mm I.D.) under isocratic conditions with methanol–0.067 M acetate buffer (70:30, v/v), pH 6.2 as mobile phase at flow-rate 1.1 ml/min. Alkyl organoiodides, which are electrochemically inactive, were made oxidizable at potential of 120 mV after post-column irradiation with low-pressure mercury lamp in a knitted PTFE tube. The photoreactor was placed in an aluminum housing full of nitrogen in order to prevent from the interference of oxygen. The detection limit for most analytes was of the order of 1–2 μg/l. The HPLC–ED method with a post-column photochemical reactor has good precision and linearity and can be readily applied to the routine determination of alkyl organoiodides in real acetic acid samples. [Copyright &y& Elsevier]

The presented work is devoted to Porasil C silica, with organic compounds bonded to its surface and capable of electron-donor–acceptor (EDA) interactions. These packings are a good base for studying interactions among stationary phases and the adsorbate molecules showing electron-donor properties. The presented work concentrates on the phases containing ketoimino groups at their surface. Copper and chromium chlorides were bonded through these to the surface. Physicochemical characteristics of the obtained packings were determined by the use of elemental analysis, differential scanning calorimetry (DSC) and inverse gas chromatography. We examined the influence of the surface modification on the retention parameters of the nucleophilic compounds. [ABSTRACT FROM AUTHOR]

A direct solid-phase microextraction (SPME) procedure has been developed and applied for the simultaneous determination of nonylphenol, nonylphenol mono- and diethoxylates and their brominated derivatives in raw and treated water at low μg l−1 concentrations. Several parameters affecting the SPME procedure, such as extraction mode (headspace or direct-SPME), selection of the SPME coating, extraction time, addition of organic modifiers such as methanol and temperature were optimized. The divinylbenzene–carboxen–polydimethylsiloxane fiber was the most appropriate one for the determination of nonylphenol ethoxylates (NPEOs) and bromononylphenol ethoxylates (BrNPEOs) by SPME–GC–MS. The optimized method was linear over the range studied (0.11–2.5 μg l−1) and showed good precision, with RSD values between 4 and 15% and detection limits ranging from 30 to 150 ng l−1 depending on the compound. The SPME procedure was compared with a solid-phase extraction–GC–MS method (C18 cartridge) for the analysis of NPEO and BrNPEOs in water samples. There was good agreement between the results from both methods but the SPME procedure showed some advantages such as lower detection limits, a shorter analysis time and the avoidance of organic solvents. The optimized SPME method was applied to determine nonylphenol and brominated metabolites in raw and treated water of Barcelona (NE Spain). [Copyright &y& Elsevier]

A flow injection gas phase chemiluminometer has been constructed for monitoring halogenated compounds which upon UV radiation consume ozone. The ozone concentration is followed by the ethylene–ozone chemiluminescent reaction and by UV absorption. The sensitivity depends on the ability of each compound to consume ozone and the limits of quantification vary from 9.6 and 25 nmol for CFCl3 and CF2Cl2 to 22.5 and 17.2 μmol for CHCl3 and CH3CCl3, respectively. [Copyright &y& Elsevier]

The ignition of hydrogen-air mixtures can cause intense explosions. To ensure the safe utilization of hydrogen fuel and prevent catastrophic explosion accidents, the inhibiting effect of flame inhibitors must be understood since they have important consequences for hazard analyses. In the present study, the detonability of hydrogen mixtures diluted with CF 3 I, H 2 O, CO 2 , and N 2 is investigated using numerical computations. The inhibiting effect of chemically active (CF 3 I, H 2 O, and CO 2) and chemically inert (N 2) diluents on the chemical length and time scales of a ZND detonation structure was studied using a detailed chemical kinetic mechanism for hydrogen oxidation. The inhibition efficiency of a halogenated compound, CF 3 I, towards quenching of hydrogen-air/oxygen gaseous detonations was also studied. As an additive, CF 3 I was found to promote detonation at lower concentrations. However, at higher concentrations, CF 3 I suppresses gaseous detonations by acting as a radical-scavenging agent. In the present study, a given retardant's effectiveness for suppressing a given detonation wave was evaluated for CF 3 I, H 2 O, CO 2 , and N 2. The combined suppression effects of CF 3 I, H 2 O, and CO 2 were also investigated. The efficacy of a composite inhibitor towards the quenching of a detonation wave was also evaluated and compared. [ABSTRACT FROM AUTHOR]

Extreme microorganism has gained interest because of their special contribution to the environmental and industrial biotechnology, particularly psychrophilic microorganisms which can live and thrive at lower temperatures. They produce enzymes with great potential to adapt to extreme conditions. In this study, a novel psychrophilic bacterial strain designated as TaeBurcu001 grew (optimally at 5 °C) on a chemically defined medium containing dalapon (refer to as 2,2-dichloropropionic acid, 2,2-DCP) as the sole carbon source. TaeBurcu001 was isolated from Galindez Island, Antarctica. Phylogenetic analysis based on 16S rRNA gene sequence (GeneBank ID MN061637) showed that TaeBurcu001 was closely related to members of the genus Psychrobacter (99%). Comparisons of phenotypic and biochemical characteristics between the isolate and the other known Psychrobacter species showed that they are very similar. Chloride ion release was detected using colorimetric assay with maximum value recorded at 0.27 mmol/L in 30 mM of 2,2-DCP. Furthermore, the partial dehalogenase sequence of Psychrobacter TaeBurcu001 (GeneBank ID MW311072) showed a very high similarity (88%) to the previously reported 2-haloacid dehalogenase (DehE) from Rhizobium sp. (GeneBank ID CAA75671). To the best of our knowledge, this is the first study reporting on the isolation and characterisation of psychrophilic bacteria able to grow on halogenated compounds as a carbon source. Results are expected to gain new insight for further studies to uncover the full potential of these microorganisms to be applied in environmental processes and the remediation of contaminated ecosystems. [ABSTRACT FROM AUTHOR]

• A fully automated sample preparation-analysis method was developed for PCBs. • g-C 3 N 4 was used as sorbent for automated disposable pipette extraction. • g-C 3 N 4 had high dispersibility in sample/solvent and strong affinity for PCBs. • 1-Undecanol droplets were essential for efficient transfer of PCBs onto g-C 3 N 4. • Improved analytical performance was achieved for PCBs. A fully automated online emulsification-enhanced disposable pipette extraction-gas chromatography-mass spectrometry (EE-DPX-GC-MS) method has been developed for the extraction of six polychlorinated biphenyls (PCBs) from environmental waters. An in-house prepared material, graphitic carbon nitride (g-C 3 N 4), was used as sorbent in a home-packed DPX device. The six PCBs studied include PCB 10, 28, 52, 153, 138 and 180. g-C 3 N 4 was characterized successfully by X-ray diffraction, elemental analysis, scanning electron microscopy, Fourier-transform infrared and Raman spectroscopy. As a C-N analogue of graphite, the two-dimensional structure of g-C 3 N 4 allows rapid analyte adsorption and desorption to take place. With a significant number of nitrogen functionalities in g-C 3 N 4 , the material dispersed well in aqueous sample, increasing the active surface area of contact between the sorbent and the sample. When coupled with a pre-emulsification step, PCBs in each portion of sample could be efficiently extracted by g-C 3 N 4 within 20 s of gentle turbulence. Under the most favorable conditions, the automated online EE-DPX-GC-MS method achieved wide dynamic working ranges with good linearity (r2 ≥ 0.998) for all analytes. Limits of detection ranging between 4.35 and 7.82 ng L−1 were attained, with enrichment factors of between 34 and 57 and relative standard deviations (RSDs) for intra- and inter-day precision of ≤ 8.95% and ≤ 12.6%, respectively. Absolute recoveries were between 69.3% and 109%. The fully automated online EE-DPX-GC-MS approach was applied to industrial wastewaters and reservoir waters where good relative recoveries of PCBs of between 89.3% and 105% were obtained, with RSDs ≤ 11.6%. [ABSTRACT FROM AUTHOR]

Many halogenated compounds have enticed substantial attention as pollutants of environmental concern and pose a serious threat to human health and the environment. To date, halogenated compounds are detected by conventional analytical methods, such as chromatography and spectroscopy. Although sensitive and accurate, the traditional methods are highly dependent on expert users, need expensive instrumentation and prolonged analysis time. Hence, rapid, accurate, and in situ detection of these chemicals is crucial to the success of early warning systems. Biosensors for detection of hazardous halocarbons meet many of the requirements for environmental application and have made considerable progress over the last few decades. This review provides a comprehensive overview of biosensors based on dehalogenating enzymes for the detection of halogenated compounds (halocarbon biosensors). The key publications that have shaped the field were included in the study. We discussed the signal transduction principles in halocarbon biosensors and classified them into potentiometric, amperometric, optical, and calorimetric biosensors. We compared halocarbon biosensors in terms of analytical features, bioreceptor (whole-cell, purified enzyme, and mini protein), source organism, immobilization method, and immobilization matrix. We chronologically discussed the progress in halocarbon biosensors and analyzed the development trends. Finally, we highlighted the challenges to halocarbon biosensors and discussed prospects, together with the recommended solutions. Image 1 • Dehalogenases as promising tool for halocarbon detection. • Whole-cells as a biocomponent in halocarbon biosensors remained a common choice. • Optical biosensors have attracted increasing attention. • The projections for the future development of halocarbon biosensors were discussed. [ABSTRACT FROM AUTHOR]

The growing concerns on the sustainability of our planet have been leading the way to the development of alternative and renewable forms of energy. One example is the use of waste (e.g. sewage sludge, forest residues, agroindustry and food processing) to produce biogas. Comprised mostly of methane and carbon dioxide, it can be used as fuel in cogeneration systems, automotive mobility and domestic heating, among other applications. The increasing interest in the use of biogas has raised some questions regarding its quality for energy valorization. To start, the carbon dioxide content must be adjusted to upgrade the calorific power and economic value and then common potentially hazardous and even toxic impurities such as carbon monoxide, hydrogen sulfur, halogens, or ammonia should be removed to ensure a correct operation. Recently, a close attention was drawn to the presence of siloxanes. These widespread emerging pollutants compromise the use of biogas for energy production due to the formation of abrasive silicon oxides after combustion that deposit on and damage several engine parts. In addition, some of them are potentially toxic and persistent, involving a threat to humans and the environment, which increased drastically the literature devoted to them in the last years. This review provides a comprehensive assessment of the literature available on biogas impurities, presenting their main effects, sampling and analytical strategies, and concentrations. A summary of removal methodologies is also presented to address the technological challenges to cope with these unwanted compounds. Image 1 • First review focused on biogas impurities produced in field-scale facilities. • Polymer bags and GC/TCD are the prevalent methods for sampling and analysis. • Levels of major impurities are higher in landfills than WWTPs or bioreactors. • Differences in VMSs content in biogas were noted between landfills and WWTPs. • Membranes and biological filters arise as promising impurities removal solutions. [ABSTRACT FROM AUTHOR]

Halogenated compounds such as polychlorinated biphenyl (PCBs) and polybrominated diphenyl ethers (PBDEs) enter wastewater treatment plants (WWTPs) via the sewage system. These organic contaminants partition between the aqueous and the biosolid phase, where the former is discharged as wastewater effluent. Biosolids from a WWTP provide a hydrophobic surface for adsorption and thus the presence and potential growth of organohalide respiring (OHR) bacteria. In this study, the aim was to assess the potential organohalide respiration capacity in wastewater biosolids by investigating actively organohalide respiring bacteria with a focus on organohalide respiration of PCBs and PCE. The results of the biosolids analysis showed increased amounts of products from PCB respiration. Simultaneously, experiments with organohalide respiration of PCE in biosolids samples showed significant decreases PCE concentration after 46 days (28–92%). Subsequently, it was evaluated if the OHR microbial populations in biosolids were similar to those present in intestinal human biofilms by applying a bioinformatic approach. The OHR populations of the communities were analyzed from existing American and Chinese human intestinal microbiomes. The overall groups Proteobacteria , Bacteroides , Actinobacteria , and Firmicutes phyla dominated the microbiomes in all datasets. The OHR groups in biosolids and intestinal biofilms included Dehalogenimonas , Dehalobacter , Desulfitibacter , Desulfovibrio , Sulfurospirillum , Clostridium , and Comamonas. The results of this study showed that several OHR phyla were present in all samples independent of origin. Wastewater and intestinal microbiomes also contained OHR phyla. Overall, the results points towards using bacterial communities in biosolids as indicators of organohalide respiration in wastewater and intestinal microbiomes, which is related to ingestion or halogenated compounds. Unlabelled Image • Organohalide respiration of PCBs and PCE in wastewater was investigated. • OHR microbial populations were analyzed from existing human intestinal microbiomes. • Microbiomes of OHR bacteria in biosolids and intestinal samples were evaluated. • Bacterial communities from WWTP and human gut were related to food ingestion. [ABSTRACT FROM AUTHOR]