Mode trace element content

SIMS has become one of the most important tools for the characterization of experimental products because of its minimal sample requirements, high spatial resolution, excellent sensitivity, and unsurpassed ability for depth-profile measurements. Most of the experimental work can be split into two different areas. The first consists of studies examining diffusion rates of different elements in minerals or melts under a variety of pressure, temperature, and fluid conditions, typically by using an isotopically enriched tracer. These analyses are done either by cutting a surface parallel to the diffusion direction and taking a traverse of spot analyses (for conditions in which profiles in the tens to hundreds of micrometers are expected) or by depth-profiling in from the mineral surface to depths of as much as 5-10 micrometers. In the latter mode, depth resolution on the tens of nanometer scale is possible (see Chapter 4). The second area is focused on determining partition coefficients for trace elements between different minerals and fluids/melts at specific temperatures, pressures, and fluid conditions, to provide the data needed to interpret trace element contents measured in natural minerals. This type of analysis typically involves spot analysis of mineral run products. 

Besides the healthy problems, trace element analysis is also very useful for commodity inspection because trace element content can provide valuable information for the detection of counterfeit products. The products with famous brand are usually the targets of counterfeit activities. Since famous brand foods, wines, cigarettes or tea products are usually produced in certain definite region. So the characteristics of the trace element contents in soil and natural water in this region will give some finger print on the products produced in this region. The mode of trace element contents is very difficult to be imitated by counterfeiters. 

Information on the element and mineral content of coals provides only a partial picture of the potential behavior of the trace elements in coal. The picture can be brought into sharper focus if we know an element s mode of occurrence (chemical form). The mode of occurrence of an element in coal determines its technological behavior, environmental impact, and economic potential, and provides insight into the geochemical processes that occurred during coalihcation. 

---