PubMed · 16855548
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2006-07-20. Safety catch.. https://doi.org/10.1038/442223b
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Mineral elements, often at the trace level, play a considerable role in physiology and pathology of biological systems. Metallogenomics, metalloproteomics, and metallomics are among the emerging disciplines which are critically dependent on spatially resolved concentration maps of trace elements in a cell or tissue, on information on chemical speciation, and on that on metal-binding coordination sites. The mini-review discusses recent progress in analytical techniques for element profiling on the genome scale, biological trace element imaging, and probing, identification and quantification of chemical species in the biological environment. Imaging of the element distribution in cells and tissue sections is becoming possible with sub-micrometer spatial resolution and picogram-level sensitivity owing to advances in laser ablation MS, ion beam and synchrotron radiation X-ray fluorescence microprobes. Progress in nanoflow chromatography and capillary electrophoresis coupled with element specific ICP MS and molecule-specific electrospray MS/MS and MALDI enables speciation of elements in microsamples in a complex biological environment. Laser ablation ICP MS, micro-SXRF, and micro-PIXE allow mapping of trace element distribution in 1D and 2D proteomics gels. The increasing sensitivity of EXAFS and XANES owing to the use of more intense synchrotron beams and efficient focusing optics provide information about oxidation state, fingerprint speciation of metal sites and metal-site structures.
A new process for the remediation of soil contaminated with hydrocarbons is proposed. The innovation consists on coupling an advanced oxidative method, using a Fenton-type catalyst, with the application of ultrasonic energy. The use of ultrasonic energy not only assists the desorption of the contaminants from the soil, but also promotes the formation of OH radicals, which are the oxidant agents involved in the oxidation process. Different Fenton-like catalysts were employed in the present study; however, the highest removal of toluene and xylenes were obtained with iron sulfate and copper sulfate, respectively. Also, hydrogen peroxide was tested at different concentrations, and it was found that increasing its concentration enhanced the removal of all the contaminants. Finally, it was demonstrated that applying ultrasonic energy to the reacting system process noticeably enhanced the global efficiency of the process due to a synergistic effect in conjunction with the hydrogen peroxide concentration and type of catalyst.
The effects of mixed anionic-nonionic surfactants, Tween40-SDS (sodium dodecyl sulfate), Tween40-SDBS (sodium dodecylbenzene sulfonate), Tween20-SDS and Tween20-SDBS, on the solubility and volatilization of naphthalene from static aqueous solutions were investigated. The experiment results indicated that mixed anionic-nonionic surfactants can solubilize naphthalene synergistically, which was resulted from the reduction in critical micelle concentration (CMC) of the mixed surfactant and the increase in micellar partition coefficient (K(mc)) of naphthalene between micelles and aqueous phase. The synergistic effects of mixed surfactants resulted in further reduction in volatilization of naphthalene than that induced by single surfactant. A positive linear correlation was found between the synergistic solubilization ratio (DeltaS) and the synergistic inhibitory capacity on naphthalene volatilization (DeltaC) in the presence of mixed surfactants. Results from this study imply that mixed surfactants can be employed in environmental remediation to formulate the needed solubility and volatilization of volatile and semivolatile compounds in aqueous solutions.