Increased extraction efficiency of acetonitrile/water mixtures for explosives determination in plant tissues
ABSTRACT The standard extraction technique for analysis of explosives in dried soils for explosives analysis uses an 18 hour cooled sonication extraction in acetonitrile (ACN). In order to eliminate possible thermal degradation of explosive analytes during the drying step, water was allowed to act as a modifier for the acetonitrile extraction solvent in extraction of un-dried plant tissues resulted. The modified extraction solvent resulted in more efficient extraction of explosives analytes from these matrices compared to extractions in 100% ACN. In order to understand this increased extraction efficiency, extractions and analyses were performed on plant tissues that had been exposed to contaminated irrigation water with varied extraction solvents. Significant increases in extractability of explosives from plant tissues were noted with increasing water ratios. These observations were investigated using gravimetric, high performance liquid chromatographic, and environmental scanning electron microscopic analysis. The increased efficiency of water modified acetonitrile extraction solvents is explained by a secondary extraction effect.
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ABSTRACT: The issue of identification and determination of explosives has especially great significance nowadays. The main reason is the threat from terrorist attacks. The toxicity of most explosive substances means that they are also the subject of environmental analyses. Explosive substances are usually detected/determined with the help of chromatographic methods. The most difficult stage of the analytical process is appropriate preparation of samples – in such a way as to selectively isolate the analysed compounds from the matrix and concentrate them. A review of the procedures for preparing samples indicates that methods of solid phase extraction are most frequently used for this purpose, especially in the form of solid phase microextraction (SPME). In the case of analysis of water and liquid waste, this method allows us to isolate analytes directly from the sample. In the case of analysis of solid samples (e.g. material from the scene of an explosion, polluted soil, sediments, plant material, samples of dust on filters), the first stage of preparation is usually solvent extraction. In the extract obtained in this way, numerous interfering compounds are usually present, which is why the second stage of the process of preparation is application of SPME. Appropriate selection of a fibre allows selective adsorption of analytes and elimination in this way of the influence of interferents.
Article: Biotransformations of explosives.Biotechnology & genetic engineering reviews 02/2001; 18:171-217. DOI:10.1080/02648725.2001.10648013 · 1.90 Impact Factor
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ABSTRACT: The enormous growth of industrialization, and the use of numerous aromatic compounds in dyestuffs, explosives, pesticides and pharmaceuticals has resulted in serious environmental pollution and has attracted considerable attention continuously over the last two decades. Many aromatic hydrocarbons, nitroaromatic compounds, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, diauxins and their derivatives are highly toxic, mutagenic and/or carcinogenic to natural microflora as well as to higher systems including humans. The increasing costs and limited efficiency of traditional physicochemical treatments of soil have spurred the development of new remediation technologies. Phytoremediation is emerging as an efficient treatment technology that uses plants to bioremediate pollutants from soil environments. Various modern tools and analytical devices have provided insight into the selection and optimization of remediation processes by various plant species. Sites heavily polluted with organic contaminants require hyperaccumulators, which could be developed by genetic engineering approaches. However, efficient hyperaccumulation by naturally occurring plants is also feasible and can be made practical by improving their nutritional and environmental requirements. Thus, phytoremediation of organics appears a very promising technology for the removal of contaminants from polluted soil. In this review, certain aspects of plant metabolism associated with phytoremediation of organic contaminants and their relevant phytoremediation efforts are discussed.Applied Microbiology and Biotechnology 01/2004; 63(2):128-35. DOI:10.1007/s00253-003-1425-1 · 3.81 Impact Factor