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Dean J.R. (2003) Methods for environmental trace analysis.Размер файла: На удаленном сервере Раздел: Химия >>Методы Книга была скачана: 2498 раз Краткое содержание/Аннотация:The field of environmental sample preparation has undergone a revolution in the last twenty five years. What was essentially a series of basic methods and procedures has developed (and continues to develop) into a new exciting area with a strong influence from instrumental approaches. This book essentially covers the traditional approaches of environmental sample preparation for both metals and organic compounds from a range of matrices.The text is arranged into twelve chapters, covering the essentials of good laboratory housekeeping, through sampling and sample storage, and finally to the relevant sample preparation for inorganic and organic compounds from environmental matrices. A further chapter is devoted to the methods of analysis that can be used for quantitative analysis. To allow the user of the book to perform experiments in an effective manner, guidelines are also offered with respect to record keeping in the laboratory. In Chapter 1, information is provided with regard to general safety aspects in the laboratory. In addition, specific guidance on the recording of numerical data (with the appropriate units) is provided, with examples on how to display data effectively in the form of tables and figures. Issues relating to sample handling of solids and liquids are also covered. Finally, numerical exercises involving the calculation of dilution factors and their use in calculating original concentrations in environmental samples are provided as worked examples. Chapter 2 is concerned with the concept of quality assurance and all that it involves with respect to obtaining reliable data from environmental samples. Particular emphasis is placed on the definitions of accuracy and precision. Finally, details on the use of certified reference materials in environmental analysis are provided. Chapter 3 involves the concept of sampling of representative sample systems. Specific details pertaining to the sampling of soil and sediment, water and air are provided. Chapter 4 considers the issues associated with the storage and preservation of samples with respect to inorganic and organic pollutants. In particular, focus is given to the retention of chemical species information in environmental matrices. Chapters 5 and 6 are focused on the specific sample preparation approaches available for the elemental analysis of pollutants from environmental matrices, principally soil and water. Chapter 5 is concerned with the methods available to convert a solid environmental sample into the appropriate form for elemental analysis. The most popular methods are based on the acid digestion of the solid matrix, using either a microwave oven or a hot-plate approach. The growing importance of chemical species information is highlighted with some specific examples. This is then followed by examples of methods to selectively remove the species without destroying its speciation. Details are provided on the methods available for the selective extraction of metal species in soil studies using either a single extraction or a sequential extraction procedure. In addition, a procedure to carry out a physiologically based extraction test on soil is provided. Finally, the role of a simulated gastro-intestinal extraction procedure for extraction of metals in foodstuffs is provided. Chapter 6 provides details of methods for the extraction of metal ions from aqueous samples. Particular emphasis is placed on liquid-liquid extraction, with reference to ion-exchange and co-precipitation. The focus in Chapters 7 and 8 is on the specific sample preparation approaches available for the extraction of organic compounds from environmental matrices, principally soil and water. Chapter 7 is concerned with the role of Soxhlet, ultrasonic and shake-flask extraction on the removal of organic compounds from solid (soil) matrices. These techniques are contrasted with newer developments in sample preparation for organic compound extraction, namely supercritical fluid extraction, microwave-assisted extraction and pressurized fluid extraction. Chapter 8 is arranged in a similar manner. Initially, details are provided on the use of solvent extraction for organic compounds removal from aqueous samples. This is followed by descriptions of the newer approaches, namely solid-phase extraction and solid-phase microextraction. Chapter 9 deals with the extraction of volatile compounds from the atmosphere. Particular emphasis is placed here on the methods of thermal desorption and purge-and-trap. Chapter 10 focuses on the methods used to pre-concentrate samples after extraction. In this situation, particular attention is paid to two common approaches, namely rotary evaporation and gas blow-down, although details of two other methods are also provided. Chapter 11 details the relevant methods of analysis for both metals and organic compounds. For elemental (metal) analysis, particular attention is given to atomic spectroscopic methods, including atomic absorption and atomic emission spectroscopy. Details are also provided on X-ray fluorescence spectrometry for the direct analysis of metals in solids, ion chromatography for anions in solution, and anodic stripping voltammetry for metal ions in solution. For organic compounds, particular attention is focused on chromatographic approaches, principally gas chromatography and high performance liquid chromatography. Details are also provided on the use of Fourier-transform infrared spectroscopy for the analysis of total petroleum hydrocarbons. The final chapter (Chapter 12) provides examples of forms that could be used to record laboratory information at the time of doing the experiment. Guidelines are given for the recording of information associated with sample pre-treatment. Then, specific forms are provided for the recording of sample preparation details associated with inorganic or organic environmental samples. Finally, guidelines are given for the recording of information associated with the analysis of metals and organic compounds. This chapter concludes with a resource section detailing lists of journals, books (general and specific), CD-ROMs, videos and Web addresses that will act to supplement this text. Finally, I should like to give a special mention to all of the students (both past and present) who have contributed to the development of interest in the field of environmental sample preparation. The achievements have been many and varied across a broad area of environmental sample preparation, but it has all been worthwhile. Dean J.R. (2003) Methods for environmental trace analysis. |
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