“…Much attention is devoted to optimization of SPE preconcentration methods for particular elements or group of elements. For instance, in the FIA-ICP-AES system, the effective preconcentration of zinc was reported for Zn complex precipitated on the walls of the knotted reactor, 331 while in another design of the FIA manifold, three cartridges packed with different sorbents were employed for trace metal fractionation, which was investigated for Mg, Al, Ca, Cr, Mn, Fe, Co, Cu, Zn, Cd and Pb, simultaneously. 332 The preconcentration of large group of trace elements, including rare earth elements from environmental samples, was reported in the SIA-ICP-AES system with on-line SPE using chitosan resin functionalized with 2-amino-5-hydroxybenzoic acid.…”