Speciation analysis is defined as the separation and quantification of different oxidation states or chemical forms of a particular element.
In the past, the determination of total element concentrations was considered to be sufficient for clinical and environmental considerations. Although the total concentration of an element is still useful to know and essential in many areas, the determination of each species is an important task. The concentration of a toxic species is more relevant in the setting of environmental and ecological standards than is the total elemental concentration. The collection, treatment and preservation of samples for quantitative analysis of species require careful consideration and planning. This separates speciation studies from procedures for "total" element determinations, and analytical chemists are faced with very difficult problems in the acquisition of accurate data. Speciation analysis is essential for predicting and modeling fate, risk, and effects while it's a must have for designing custom - tailored treatment strategies. Wastewater treatment failures are often results of not understanding the individual chemistry at different stages of treatment. The speciation of an element can directly affect the efficiency of the treatment process. Unfortunately, speciation analysis is not as common as traditional total elemental analysis because while speciation data is accepted by some regulators, there are no set laws or regulations on this matter. We believe that the lack of species-specific regulations is due to the absence of methods that can reliably measure the analytes of interest at the regulatory levels. For instance, the analytical methods currently available for elements such as arsenic and chromium are either not selective enough or do not provide sufficiently low detection limits.
Another important issue for speciation analysis is its cost. Even though it has been shown time after time that speciation analysis can save time and money with respect to remediation and risk assessment, it is usually more expensive than routine elemental analyses. One of the most important aspects of speciation analysis is the issue of preservation. In the ideal world, we would be able to perform speciation analysis in the field. Unfortunately, this is still not possible for most analytes of interest so even the most sophisticated analytical methods for the determination of an element's speciation are “useless” if it cannot be assured that the species distribution in the sample remains unchanged between sample collection and analysis.