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How are chelating resins used to collect trace metals from seawater?

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chemical structure of cation exchanger — ion-exchange reaction Figure 1: Chemical structure of cation exchanger. The exchangeable ions are marked ⁺. The whole structure is permeated by solvent molecules, usually water (not shown).

Chelating resins are specialized polymers, typically styrene-divinylbenzene structures modified with iminodiacetate groups, used to collect trace metals from seawater.12

Unlike standard ion-exchange resins that rely on simple electrostatic attraction, chelating resins function by forming stable, ring-like complexes with metallic elements. These functional groups are highly selective, allowing them to bind specific metal ions while excluding others, such as alkali metals. In the context of seawater analysis, these resins act as effective tools for isolating and concentrating trace amounts of metals that would otherwise be difficult to detect or extract due to their low concentrations and the complex chemical environment of the ocean.132

Additionally, these resins can exhibit further utility; for instance, a copper-loaded chelating resin is capable of adsorbing trace amino acids from seawater through coordination.2