Preconcentration strategies for trace metals including REEs in seawater and porewater by employing commercial chelating resin – A review

Trace metals, including Rare Earth Elements (REEs), have been widely used in oceanography, acting as tracers to evaluate biogeochemical cycles, water mass transport, rock-water interaction, and external input or deposition. However, a reliable and reproducible determination is still challenging due to many factors, especially matrix effects from seawater matrices (seawater and porewater). Since trace element determination in seawater matrices is still not a routine procedure, the ongoing analytical development in this field has thus eventually attracted both analytical and marine geochemistry communities. Therefore, this paper reviews analytical methods, major challenges, calibration strategies, and future outlooks for trace elements preconcentration in seawater matrices using various commercially available chelating resins. It is known that there has been a move towards sample treatment simplification, a wide range of operating pH and sample matrices, onboard preconcentration, and simultaneous multielement (trace metals including REEs) analysis, demonstrating that there are still emerging analytical and environmental chemistry issues related to this field.