Occurrence, behavior and effects of nanoparticles in the environment.

Biogeochemistry of the Human Environment.- The Biosphere.- Soils.- Waters.- Air.- Plants.- Humans.- Biogeochemistry of Trace Elements.- Trace Elements of Group 1 (Previously Group Ia).- Trace Elements of Group 2 (Previously Group IIa).- Trace Elements of Group 3 (Previously Group IIIb).- Trace Elements of Group 4 (Previously Group IVb).- Trace Elements of Group 5 (Previously Group Vb).- Trace Elements of Group 6 (Previously Group VIb).- Trace Elements of Group 7 (Previously Group VIIb).- Trace Elements of Group 8 (Previously Part of Group VIII).- Trace Elements of Group 9 (Previously Part of Group VIII).- Trace Elements of Group 10 (Previously Part of Group VIII).- Trace Elements of Group 11 (Previously Group Ib).- Trace Elements of Group 12 (Previously Group IIb).- Trace Elements of Group 13 (Previously Group IIIa).- Trace Elements of Group 14 (Previously Group IVa).- Trace Elements of Group 15 (Previously Group Va).- Trace Elements of Group 16 (Previously Group VIa).- Trace Elements of Group 17 (Previously Group VIIa).

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Trace Elements From Soil to Human

The unique and tunable properties of carbon-based nanomaterials enable new technologies for identifying and addressing environmental challenges. This review critically assesses the contributions of carbon-based nanomaterials to a broad range of environmental applications: sorbents, high-flux membranes, depth filters, antimicrobial agents, environmental sensors, renewable energy technologies, and pollution prevention strategies. In linking technological advance back to the physical, chemical, and electronic properties of carbonaceous nanomaterials, this article also outlines future opportunities for nanomaterial application in environmental systems.

Environmental applications of carbon-based nanomaterials.

The analysis of various parameters of metal oxides and the search of criteria, which could be used during material selection for solid-state gas sensor applications, were the main objectives of this review. For these purposes the correlation between electro-physical (band gap, electroconductivity, type of conductivity, oxygen diffusion), thermodynamic, surface, electronic, structural properties, catalytic activity and gas-sensing characteristics of metal oxides designed for solid-state sensors was established. It has been discussed the role of metal oxide manufacturability, chemical activity, and parameter's stability in sensing material choice as well.

Metal oxides for solid-state gas sensors: What determines our choice?

Adsorption of heavy metals on conventional and nanostructured materials for wastewater treatment purposes: A review

The state of the art and the potential of sample screening systems (SSS) for the expeditious, reliable selection of samples to meet the requirements of customers and legislation is presented and discussed. The underlying procedures use simple equipment and operations and provide a yes/no binary response that occasionally requires confirmation. After a brief discussion of the distinction between `screening' and `analysis' and the principal features of analytical screening systems, the main aims and features of SSS are presented. Several classifications of these allow one to offer a general view of the topic. Representative examples are classified according to the complexity of the sample pretreatment required, and are used to demonstrate the impact SSS may have on analytical chemistry in the next century.

Sample screening systems in analytical chemistry

Two phenoxyacid herbicides (2,4-D and MCPA) and their six corresponding phenols were determined in soil by using gas chomatography with electron impact mass spectrometry (GC/MS) for confirmation/quantitation. An automatic extraction (leaching), preconcentration, and cleanup (sorption) module was developed to extract the eight compounds from soil. The average recovery of all species, spiked to soil at microg/kg-mg/kg levels, was 95% (average standard deviation +/- 5%). A plot of agricultural clayey soil (approximately 12 m2) was contaminated with both herbicides (approximately 96 g/m3, depth 10 cm, density 1.23 g/cm3) and irrigated with (17 mm) at variable time intervals. Both herbicides and their corresponding phenol compounds were monitored at different soil depths over a 50 day period. The degradation of both herbicides in the surface layer (t(1/2) approximately 5 days) is a result of photodecomposition and microbial action; in the deeper layers, the degradation products occur in lower proportions by effect of leaching and are also the result of microbial action. The six phenol metabolites are only detected in the surface layer as they form preferentially by photodecomposition. The main metabolites (viz. 2,4-DCP for 2,4-D and 4-C-2-MP for MCPA) are formed within 24 h after the soil is contaminated; their concentration peaks are at day 8 in the absence of irrigation.

Study of the degradation of the herbicides 2,4-D and MCPA at different depths in contaminated agricultural soil.

Gas chromatographic flow method for the preconcentration and simultaneous determination of antioxidant and preservative additives in fatty foods

Direct olive oil authentication: detection of adulteration of olive oil with hazelnut oil by direct coupling of headspace and mass spectrometry, and multivariate regression techniques.

The analytical potential of C[sub 60] fullerenes as sorbent materials for preconcentration of metal traces by formation of neutral chelates was studied for the first time in this work. The model system used for this purpose was the determination of lead traces in waters by using ammonium pyrrolidinedithiocarbamate as ligand. The chelate is formed in a continuous-flow system, sorbed on a C[sub 60] fullerene minicolumn, and subsequently eluted for transfer to an atomic absorption spectrometer. Two other simultaneous batches of experiments were performed in parallel by using C[sub 18] bonded silica and activated carbon as sorbents in order to study the features of the new sorbent material and its advantages. The primary assets of C[sub 60] fullerenes in this respect are a high sensitivity arising from efficient adsorption and also high selectivity derived from the special features of this new type of sorbent material. 27 refs., 3 figs., 2 tabs.

Mercedes Gallego

Papers

Sample screening systems in analytical chemistry

Study of the degradation of the herbicides 2,4-D and MCPA at different depths in contaminated agricultural soil.

Gas chromatographic flow method for the preconcentration and simultaneous determination of antioxidant and preservative additives in fatty foods

Direct olive oil authentication: detection of adulteration of olive oil with hazelnut oil by direct coupling of headspace and mass spectrometry, and multivariate regression techniques.

Fullerenes as Sorbent Materials for Metal Preconcentration