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Organometallic Compound Analysis in Environmental Samples

Environment: Water and Waste

  1. Les Ebdon,
  2. Andy Fisher

Published Online: 15 SEP 2006

DOI: 10.1002/9780470027318.a0852

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Ebdon, L. and Fisher, A. 2006. Organometallic Compound Analysis in Environmental Samples. Encyclopedia of Analytical Chemistry. .

Author Information

  1. University of Plymouth, Devon, UK

Publication History

  1. Published Online: 15 SEP 2006

Abstract

Many organometallic species exist in the environment and these may range from being completely nontoxic, e.g. the arsenic compound arsenobetaine, to exceptionally toxic, e.g. methyl mercury. Compounds of intermediate toxicity, such as the arsenic species dimethylarsinic acid and monomethylarsonic acid also exist. Determining the chemical form or speciation of samples is vital in environmental impact assessment as it affects bioavailability and mobility in the environment. Speciation analysis usually comprises a number of analytical steps. Sampling and sample storage are critical and must be performed in such a way that ensures a representative sample whilst preventing changes in speciation or losses of some of the more labile species. Sample preparation normally requires the extraction of the species of interest from the sample materials. This may be achieved in a number of ways that are discussed in detail in the relevant section. Sample cleanup and derivatization methods that may be required if gas chromatographic methods of analysis are to be used are also discussed. The actual sample analysis stage is discussed in detail and this concentrates mainly upon different chromatographic techniques coupled with assorted atomic spectrometric methods of detection. This is because these so-called “coupled” techniques are used for the majority of speciation analyses. Other nonchromatographic methods of sample introduction to atomic spectrometric detection, such as hydride generation (HG), are also discussed together with techniques including more conventional detectors for the chromatographic techniques (such as ultraviolet (UV)/visible, fluorescence, flame ionization detectors (FIDs), electrochemical detectors, etc.), electrochemical methods, nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. In addition to obtaining quantitative data, techniques such as NMR and IR spectroscopy may be used to obtain structural information on individual species.

Method validation is as important for speciation analysis as it is for any other analysis. This may be achieved using mass balance data, the analysis of certified reference materials (CRMs) or using completely independent analysis techniques. The text gives an overview of all stages of the analysis, highlighting potential pitfalls and areas of uncertainty.