Towards Development of a Trace Element Sampling System: In Situ Pre-Concentration Using a Bi-Directional Pump

Abstract

A method to pre-concentrate iron (Fe) from seawater samples in the laboratory has been developed. The expectation is eventual deployment in unattended platforms in hard to access regions as well as to act as an alternative to the current rosette-based sampling system for trace elements. The system consists of a bi-directional pump (milliGAT), a holding coil, a multi-position selection valve, and external columns packed with a Toyopearl AF-Chelate-650® resin. From measurements of iron spiked water samples before and after pre-concentration on the resin, it was found that the iron present in the sample was successfully adsorbed on to the resin. The pre-concentration efficiency of the resin is 97.47% ± 0.82%, and the maximum capacity of the resin measured during experiments is 446.71 ± 3.76μmol Fe L-1. A detection limit for the analytical method of 355pM Fe was obtained.