Fractionation and speciation were defined by Templeton
et al. [10] with IUPAC recommendations as the “process of
classification of an analyte or a group of analytes from a
certain sample according to physical (e.g. size, solubility) or
chemical (e.g. bonding, reactivity) properties”, and speciation
of an element as “distribution of an element amongst
defined chemical species in a system”.