Mossbauer Spectroscopy for the Study of Elemental Speciation

Similar to other quantitative analytical approaches, the area under the spectral lines is proportional to the number of Mossbauer atoms detected. Practically, in one approach, a calibration graph of the area value of a series of external analogous samples with known concentrations would be constructed and compared with that of the unknown samples. In another approach a graph of the area value of unknown sample added with analogous samples with a series of known concentration can be drawn for calibration. Both approaches are common methods employed in instrumental analysis. 

Quantitative analysis could be used to measure the concentration of the element component in a sample as well as to identify the oxidation state and phase. In a study by Korecz et al., the Mossbauer spectrum is used to follow, quantitatively, the course of incorporation of iron into the corundum lattice. The composition of the iron aluminium oxide formed was also found to be FeAlsOig, which means an aluminium oxide polymer with an iron atom in every five aluminium atoms.  

Bonchev et al. studied the abdomen of 50 ants by smearing them with an absorbent of tin oxide. These authors then analyzed the line width caused by the movement of the living ants and calculated the rate of motion in the ant nest.  

Mossbauer atoms under certain conditions can show certain types of profile in observed spectra. In specifying some unknown samples, the spectra can be compared with those of known samples, and, hence, the components of the unknown samples might be deduced. 

Conventionally, a new substance would be added as a standard into a sample. If the substance is identical with a constituent of the sample, an increase of intensity without any other changes can be observed while if the substance matches nothing in the sample, new lines would appear in spectrum. This approach sometimes may be frustrated when the spectra of two different substances are similar. To eliminate such problems, an external magnetic field would be added to complicate the spectrum, in order to reduce the possible interference caused by the spectra of different substances. 

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This section will introduce the application of Mossbauer spectroscopy for the study of elemental speciation in environmental and biological samples. The... 

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