Environmental issues analytical techniques

As already noted, the chemical composition of petroleum and petroleum products is complex and may change over time following release into the environment. These factors make it essential that the most appropriate analytical methods are selected from a comprehensive hst of methods and techniques that are used for the analysis of environmental samples (Dean, 1998 Miller, 2000 Budde, 2001 Sunahara et al., 2002 Nelson, 2003 Smith and Cresset, 2003). But once a method is selected, it may not be the ultimate answer to solving the problem of identification and, hence, behavior (Patnaik, 2004). There are a significant number of petroleum hydrocarbon-affected sites, and evaluation and remediation of these sites may be difficult because of the complexity of the issues (analytical, scientific, and regulatory not to mention economic) regarding water and soil affected. 

Subject areas for the Series include solutions of electrolytes, liquid mixtures, chemical equilibria in solution, acid-base equilibria, vapour-liquid equilibria, liquid-liquid equilibria, solid-liquid equilibria, equilibria in analytical chemistry, dissolution of gases in liquids, dissolution and precipitation, solubility in cryogenic solvents, molten salt systems, solubility measurement techniques, solid solutions, reactions within the solid phase, ion transport reactions away from the interface (i.e. in homogeneous, bulk systems), liquid crystalline systems, solutions of macrocyclic compounds (including macrocyclic electrolytes), polymer systems, molecular dynamic simulations, structural chemistry of liquids and solutions, predictive techniques for properties of solutions, complex and multi-component solutions applications, of solution chemistry to materials and metallurgy (oxide solutions, alloys, mattes etc.), medical aspects of solubility, and environmental issues involving solution phenomena and homogeneous component phenomena. 

Increasing registration requirements for the product and the production process as well as environmental issues also add a significant technical and analytical dimension to the development. This particularly applies to products derived from biotechnology. Compared to conventional biological products, the final product is usually much better defined and its manufacturing process can be better controlled. But it requires the application of a variety of quite sophisticated techniques to do so. 

The reader will be referred to much more extensive review articles or books for details on their wide range of appHcations. The annual review issue of the journal Analytical Chemistry is a good starting point. In these review issues, alternating years cover techniques and appHcations. The first are a series of reviews focusing on the variety of analytical techniques, principally the various types of chromatography and spectrometry. The second is divided into a series of articles on areas such as pharmaceuticals, polymer analysis, petroleum and other fossil fuels, and environmental analyses. These issues usually appear as the mid-June volume of the journal. 

The online coupling of a separation device with mass spectrometry is an analytical approach that can help in the analysis of real-world samples such as environmental samples and biological tissues and fluids. This online marriage between two stand-alone analytical techniques can provide an unequivocal characterization of individual components of such complex samples and greatly increases the information content of those components. Several issues that must be addressed to achieve an ideal combination. A major concern is the pressure mismatch. The solvent incompatibility also becomes an issue in the coupling of LC and CE with mass spectrometry. Thus, online coupling requires an interface that can transport the separated components into the ion source without affecting their resolution or the performance of a mass spectrometer. Not all types of mass spectrometers... 

Thermoplastics processing operations produce emissions into the air, wastewater, and solid waste resulting from both polymers and additives. Most important are volatile organic compounds emitted from heated cylinders and molds. The identification of such volatiles and the development of analytical techniques for measuring their concentration in the workplace are of paramount importance to establish or revise threshold limit values that would minimize exposure to hazardous chemical substances. Environmental issues in polymer processing are reviewed in References 18 and 19. 

Customer engagement. This issue takes a holistic view of sales and customer relationships. Customer relationships management and business analytics techniques are used to provide customized customer services on a global scale. From the supply chain perspective, it changes cost optimization focus to customer service focus implying not only high fill rates and responsiveness but also social responsibility, supply chain transparency, and environmental consciousness (Carter and Rogers 2008 Danese and Romano 2013). 

No analytical method is perfect. Spectral interpretation is still difficult, and standard spectra databases are scarce. The issues of quantification, comparison with data collected by other methods, and scale up are important, especially in spectromi-croscopy studies. Radiation damage and sectioning artifacts can make analysis of susceptible samples difficult. The biggest obstacle to widespread use of NEXAFS spectroscopy, microscopy, and spectromicroscopy in environmental studies remains the extremely limited number of such instruments. Typically, each beamline allocation committee receives 2 or 3 times as many requests for time as is available. Studies, when granted, are usually for 2-5 days every 4-6 months. Thus, scientists have to be very selective about the types of questions and samples that they choose to examine using these techniques. Continued pressure and education from the scientific community will be needed to increase the number of beamlines suitable for NOM studies in the future, even as new synchrotron facilities are planned or built. 

In parallel with recent developments in GC, multidimensional HPLC (LC x LC) is now also finding application in environmental analysis.33 The combination of two sufficiently different separation dimensions (e.g., NP-HPLC x RP-HPLC or IC x RP-HPLC), however, remains difficult because of the solvent compatibility issues discussed above. Here, too, HILIC may bring about a significant improvement, since its mobile phase requirements are much closer to RP-HPLC than those of other liquid chromatographic techniques.34 In contrast to GC x GC, LC x LC cannot be implemented with a (thermal) modulator that collects the analytes after the first separation dimension and reinjects them into the second column it is most practically realized with a double-loop interface that alternately collects and transfers the analytes from the first to the second dimension (Figure 13.7). Even though the second dimension chromatogram is also very fast, detection is not normally a problem since the peak widths in the second dimension are usually still of the order of 1-2 s. 

Despite the remarkable sensitivity of modern instrumental detection techniques, analysis of environmental water samples nearly always requires enrichment of the analytes. This, together with separation from the matrix, are the two main functions of sample preparation appropriate sample preparation techniques address both issues at the same time, while striving to impose as few restrictions as possible on the subsequent instrumental determination (separation and detection). Sample preparation is strongly dependent on the nature of the analyte and the matrix, particularly with regard to its volatility and polarity. Figure 13.8 gives a general overview of common sample preparation (enrichment) techniques for aqueous and other matrices. 

Steroid hormones are found as pollutants in drinking water, waste water, river and sediments. The major concerns of analytical methodologies for monitoring steroid hormones from environmental samples are extraction techniques from aqueous or solid matrices. Since sample volume or amount is not an issue in most cases, SPE is the method of choice. Both LC-MS/MS and GC-MS technologies are broadly applied for steroid analyses of environmental samples, such as LC-MS/MS analyses of steroid hormones in effluents of wastewater treatment plants [100] and estrogens in water [101,102], and GC-MS analyses of steroid hormones in environmental water [34,45, 78, 79], A study by Grover and colleagues showed that GC-MS was the simplest technique in determination of steroid hormones in environmental water samples, but lack of sensitivity LC-MS/MS was more sensitive than GC-MS, but susceptible to matrix interferences and GC-MS/MS was the recommended technique, because it was more selective and sensitive than GC/MS and LC-MS/MS [103],... 

Changes in the focus of SFE can be easily followed through its reported applications. Thus, in 1993 [3], environmental applications prevailed (45.9% versus 21.9% devoted to foods and 11.6% to industrial analyses). By 1996, however, SFE applications to food analysis had risen to 38%, environmental uses fallen to 41% and industrial analyses levelled off at 11% [48]. More recently [17], the extraction of food components (particularly fat) has become one of the major applications of SFE, so much so that the current boom in SF extractor sales has been ascribed to it. The book by Luque de Castro et al. [3] contains comprehensive tables of SFE applications in various fields. Also, one review of SFE in food analysis [148] includes four tables with applications involving the extraction of fat from various types of sample (viz. meat and animal products, fish, cereal, seed and animal feed, plants and vegetables). On a more specific level, Eller and King reviewed determinations of the fat content in foods [149]. Finally, the Analytical Chemistry issues devoted to reviewing techniques provide periodic updates on SFE and SFC [150]. 

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