Sources of error in speciation analysis

The main sources of error in trace element speciation referred to both approaches determination of well defined chemical species and species operationally defined are discussed. For the first three steps of the analysis: sampling, storage and sample pre-treatment errors are examined in common for both approaches. Possible errors are discussed separately for the rest of the steps. For speciation of well defined chemical species, extraction taking into account the type of solvent and the type of method, the derivatization step, the separatin and the use of hyphenated techniques are considered. For species operationally defined : extraction and final determination are discussed. The need of harmonized protocols for single and sequential extraction are pointed out.