Environmental analysis metal speciation

One place where there is potentially more use for NMR in soil and environmental analysis is in speciation of soil components. Using a broadband NMR instrument, many different elements can be analyzed, and it can be used to differentiate between species such as P04 3, MP04 2, and M2P04 1 (where M represents a metal). This potential, however, has not been exploited to any great extent [18-21],... 

There are few methods which can measure well-defined metal fractions with sufficient sensitivity for direct use with environmental samples (approach B in Fig. 8.2). Nevertheless, this approach is necessary in the experimental determination of the distribution of compounds that are labile with respect to the time scales of the analytical method. Recent literature indicates that high-performance liquid (HPLC) and gas chromatographic (GC) based techniques may have such capabilities (Batley and Low, 1989 Chau and Wong, 1989 van Loon and Barefoot, 1992 Kitazume et al, 1993 Rottmann and Heumann, 1994 Baxter and Freeh, 1995 Szpunar-Lobinska et al, 1995 Ellis and Roberts, 1997 Vogl and Heumann, 1998). The ability to vary both the stationary and mobile phases, in conjunction with suitable detector selection (e.g. ICP-MS), provides considerable discriminatory power. HPLC is the superior method GC has the disadvantage that species normally need to be derivatised to volatile forms prior to analysis. Capillary electrophoresis also shows promise as a metal speciation tool its main advantage is the absence of potential equilibria perturbation, interactions... 

Mach, M.H., Nott, B., Scott, J.W., Maddalone, R.F. and Whiddon, N.T. (1996) Metal speciation survey of environmental methods of analysis. Water Air Soil Poll, 90,... 

Buffle, J. and M.-L. Tercier-Waeber. 2005. Voltammetric environmental trace-metal analysis and speciation From laboratory to in situ measurements. Trends Anal. Chem. 24 172-191. 

A case that joins the problems of trace organic and inorganic analysis is speciation analysis, whose importance has been appreciated in the last few decades. Speciation studies became the center of interest of inorganic analysts when they demonstrated that various derivatives of the same element can exert fully different chemical and biological activities. Speciation analysis requires determination, at the trace level, of organic compounds of metals and nonmetals in various environmental objects. These compounds can be fully of anthropogenic origin... 

European policies. With the development of the Single Market the exchange of goods and services required agreement on chemical, biological and physical measurements between trade partners, and research demands arose for a wide variety of sectors. Most importantly in the field of environmental analysis, the first CRMs for element speciation and fractionation for metal mobility assessment were issued. 

The Laboratory of Applied Analytical Chemistry at the Warsaw University, Chemistry Department works on environmental analytical chemistry, development of analytical methods for determination of trace metals in environmental samples and speciation analysis as a modem tool for environmental risk assessment. 

A variety of methods for the determination of total metals and metal species/fractions have been described. While the most common method of sample decomposition of environmental samples is probably acid digestion, other approaches, most notably the use of fusion, have some specialist application areas, e.g. geological samples. The area of metal speciation is an ever expanding one, with new approaches being developed and evolving on a regular basis. The major limitation to this area of activity is the development of robust and reliable approaches to analysis. Some selected examples have been provided to assist the reader to evaluate some of the procedures that have already been developed. However, after reading this chapter you will have quickly realized that the methods are limited to only a few metal species. 

Chaney RL. 1988. Metal speciation and interaction among elements affect trace element transfer in agricultural and environmental food-chains. In Kramer JR, Allen HE, eds. Metal speciation Theory, analysis, and application. Chelsea, Ml Lewis Publishers, 219-260. 

In some cases they are unsuitable for direct trace analysis in complex matrix samples, because of spectral and chemical interferences, or for studies on metal spe-ciation. Due to strong environmental impact, metal ion determination and speciation have been given significant attention in the last few years. 

Groenenherg, J. E., G. F. Koopmans, and R. N. J. Comans. 2010. Uncertainty analysis of the nonideal competitive adsorption—Donnan model Effects of dissolved organic matter variahihty on predicted metal speciation in soil solution. Environmental Science Technology 44, no. 4 1340-1346. 

Principles and Characteristics The fastest growing area in elemental analysis is in the use of hyphenated techniques for speciation measurement. Elemental spe-ciation analysis, defined as the qualitative identification and quantitative determination of the individual chemical forms that comprise the total concentration of an element in a sample, has become an important field of research in analytical chemistry. Speciation or the process yielding evidence of the molecular form of an analyte, has relevance in the fields of food, the environment, and occupational health analysis, and involves analytical chemists as well as legislators. The environmental and toxicological effects of a metal often depend on its forms. The determination of the total metal content... 

In the analysis of clinical, biological and environmental samples it is often important to have information on the speciation of the analyte, e.g. metal atoms. Thus an initial sample solution may be subjected to a separation stage using chromatography or electrophoresis. Measurements may, of course, be made on fractions from a fraction collector, but with plasma sources, interfacing in order to provide a continuous monitoring of the column effluent can be possible. This relies upon the ability of the high-temperature plasma to break down the matrix and produce free ions. 

Multi-element trace analysis is an important prerequisite for the quality assurance of foodstuffs with respect to the characterization of non-essential, toxic and essential (nutrient) elements as pollutions or as mineral elements relevant to health. Contamination with heavy metals such as Cd, Pb or Hg has become a serious problem with increasing environmental (artificial) contamination e.g., due to industrial pollution. The increasing use of inorganic mass spectrometric techniques (especially of ICP-MS) in the analysis of foodstuffs for multi-element analysis of trace elements or the detection of selected elements and species at a low concentration level has resulted from advances in very sensitive and quantitative measurements of metals, metalloids and several non-metals, including their speciation. 

The humantoxic and ecotoxic effects of a metal depend strongly on its binding form [STUMM and KELLER, 1984]. Speciation of the heavy metal binding forms in the environmental compartments hydrosphere, atmosphere, and pedosphere is of considerable importance [LUND, 1990]. In most cases the individual species have to be separated before analysis [FUCHS and RAUE, 1981 FRIMMEL and SATTLER, 1982],... 

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