Eric Jover

Characterization of benzothiazoles, benzotriazoles and benzosulfonamides in aqueous matrixes by solid-phase extraction followed by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry.

Benzothiazoles, benzotriazoles and benzosulfonamides are high-production-volume chemicals found in various environmental aqueous samples that should be considered as emerging pollutants. This study examines the suitability of comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOF-MS) for the characterization of benzothiazoles, benzotriazoles and benzosulfonamides in aqueous matrices. Solid-phase extraction was optimized in order to ensure the proper preconcentration of these contaminants prior to their analysis. Column selection, in both the first and second dimensions, was optimized to ensure a good chromatographic separation of the target analytes and of the potential interfering compounds extracted from the matrix. Several column phases were tested. The combined power of two-dimensional separation was fully illustrated by identifying minor compounds and avoiding the overestimations usually made by one-dimensional systems. Finally, the suitability of GC x GC-TOF-MS to quantify the aforementioned emerging pollutants was proven by determining those pollutants in several real samples such as river water, effluent from a wastewater treatment plant, and raw sewage.

Occurrence and fate of benzothiazoles and benzotriazoles in constructed wetlands.

A suite of benzothiazoles and benzotriazoles was analysed by comprehensive multi-dimensional gas chromatography coupled to time-of-flight mass spectrometry in four different wastewater treatment systems. The selected wastewater treatment systems include one conventional wastewater treatment plant (WWTP) and for the first time, two constructed wetlands. Although benzothiazole (BT), 2-(methylthio)benzothiazole (MTBT), 2-hydroxybenzothiazole (OHBT) and benzotriazole (BTri) occurred in all the raw wastewater samples, 4- and 5-methylbenzotriazoles (4- and 5-TTri) were only detected in the industrially impacted wastewater. Concentrations of benzothiazoles and benzotriazoles in raw wastewater ranged from 0.2 to 2.2 microg L(-1) and from 0.06 to 36.2 microg L(-1), respectively. The benzothiazoles removal efficiencies ranged from zero to up to 80% in the conventional WWTP and from 83 to 90% in constructed wetlands. For BTri, removal efficiencies ranged from 65 to 70% and from 89 to 93% in conventional WWTP and constructed wetlands, respectively. The higher performance of CWs in the removal of these compounds might be attributed to the contribution of biodegradation, photodegradation and plant uptake.

Functionalization of carbon nanotubes by water plasma

Multiwall carbon nanotubes grown by plasma enhanced chemical vapour deposition were functionalized by H(2)O plasma treatment. Through a controlled functionalization process of the carbon nanotubes (CNTs) we were able to modify and tune their chemical reactivity, expanding the range of potential applications in the field of energy and environment. In particular, different oxygen groups were attached to the surfaces of the nanotubes (e.g. carboxyl, hydroxyl and carbonyl), which changed their physicochemical properties. In order to optimize the main operational parameters of the H(2)O plasma treatment, pressure and power, a Box-Wilson experimental design was adopted. Analysis of the morphology, electrochemical properties and functional groups attached to the surfaces of the CNTs allowed us to determine which treatment conditions were suitable for different applications. After water plasma treatment the specific capacitance of the nanotubes increased from 23 up to 68 F g(-1) at a scan rate of 10 mV s(-1).

Systematic characterisation of long-chain aliphatic esters of wool wax by gas chromatography–electron impact ionisation mass spectrometry

A detailed structural characterisation of the aliphatic high-molecular-mass esters extracted from raw wool based on high-temperature gas chromatography-electron impact ionisation mass spectrometry is described. The raw wool esters extracted are in the range of C37 to C54 (i.e., molecular mass 550-788). The selected ion chromatogram exhibited four isomers for the esters with an odd number of carbon atoms (i:a, i:n, a:n and n:n) and five for those with an even number of carbon atoms (i:i, a:a, i:n, a:n and n:n). Isomeric structural elucidation is discussed with respect to the long-chain fatty acid and long-chain fatty alcohol structures, on the basis of chromatographic retention behaviour and mass spectral information.

Assessment of the emission of PCDD/Fs and dioxin-like PCBs from an industrial area over a nearby town using a selective wind direction sampling device

The development of new sampling devices or strategies to assess the concentration of persistent organic pollutants (POPs) in the environment has increased in the last two decades. In this study, a selective sampling device was used to evaluate the impact of potential local sources of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) and dioxin-like polychlorinated biphenyl (dl-PCBs) emissions on the ambient air levels of such compounds in a town near an important industrial estate. Average concentrations of target compounds of up to 2.5 times for PCDD/Fs and 2 times for dl-PCBs were found to come from the industrial state confirming this area as the main responsible for the majority of such compounds reaching the town. This finding was supported by a PCDD/F and dl-PCB sample profile analysis and a principal component analysis (PCA), which established a direct link between the dioxin-like compounds found in the samples collected in the town and their source.

Advances in the determination of degradation intermediates of personal care products in environmental matrixes: a review.

In this review, recent methods developed for the determination of degradation intermediates of personal care products in environmental matrixes focusing on the extraction and determination steps are discussed. The five classes of personal care products evaluated are stimulants, fragrances, sunscreens, antimicrobials, and insect repellents. Methods are critically reviewed in terms of the analytical steps involved in the analysis, sample pretreatment, separation, and detection as well as the different confirmation strategies employed. Preconcentration from aqueous matrixes was performed by solid-phase extraction, liquid–liquid extraction, or solid-phase microextraction, allowing the simultaneous extraction of parent compounds and their degradation intermediates. Following the extraction and cleanup steps, the identification and quantification of degradation intermediates of personal care products at environmental levels (i.e., parts per trillion to parts per billion range) is usually performed by using mass spectrometry techniques such as single quadrupole mass spectrometry and more recently by time-of-flight mass spectrometry or tandem mass spectrometry. The main scope of this review is to critically evaluate the current state of the art of the analytical techniques used and to identify the research needs in the determination of degradation intermediates of personal care products in environmental matrixes.

Photo-solid-phase microextraction of selected indoor air pollutants from office buildings. Identification of their photolysis intermediates.

Photo-solid-phase microextraction (photo-SPME) has been employed to study the photolysis of three common indoor air pollutants: coumarin, butylated hydroxytoluene, 2,6-diisopropylnaphthalene. Analytes were first extracted by SPME, and the fibre was subsequently exposed to an irradiation source (i.e. xenon arc or low-pressure mercury lamp) for the selected time (from 2 to 120 min). Analyses of the irradiated fibres were carried out by gas chromatography-mass spectrometry (GC-MS) detection. Photodecay kinetics exhibited a first-order behaviour and their rate constants and half-life times were estimated. Twenty-five photoproducts have been tentatively identified by means of their mass spectra. On the basis of the identified transformation compounds, some photodegradation pathways were proposed. The photoformation-photodecay kinetics of the identified by-products were also monitored by photo-SPME. To the best of our knowledge, photolytic routes for coumarin, butylated hydroxytoluene and 2,6-diisopropylnaphthalene have not been previously investigated.

Water Plasma Functionalized CNTs/MnO2 Composites for Supercapacitors

A water plasma treatment applied to vertically-aligned multiwall carbon nanotubes (CNTs) synthesized by plasma enhanced chemical vapour deposition gives rise to surface functionalization and purification of the CNTs, along with an improvement of their electrochemical properties. Additional increase of their charge storage capability is achieved by anodic deposition of manganese dioxide lining the surface of plasma-treated nanotubes. The morphology (nanoflower, layer, or needle-like structure) and oxidation state of manganese oxide depend on the voltage window applied during charge-discharge measurements and are found to be key points for improved efficiency of capacitor devices. MnO2/CNTs nanocomposites exhibit an increase in their specific capacitance from 678 Fg−1, for untreated CNTs, up to 750 Fg−1, for water plasma-treated CNTs.