Transportable EDXRF analysis of environmental water samples using Amberlite IRC748 ion-exchange preconcentration

Transportable energy-dispersive X-ray fluorescence spectrometers allow on-site assessment of metal-contaminated soils, sediments and other solids. Multi-element analysis of liquid samples, such as surface water, groundwater, acid leach and aqueous soil extracts, would enhance on-site environmental assessments. However, transportable spectrometers typically have detection limits for metals in waters of approximately 1-10mg l^-1, whereas many toxic elements are regulated at concentrations of 1-100 μg l^-1. If detection limits for this technique can be lowered, then only one analytical tool, a transportable XRF spectrometer, may be sufficient for remote areas, increasing program flexibility and reducing the amount of equipment that needs to be purchased, transported and operated. This research develops an in-field preconcentration technique using Amberlite IRC748 cation-exchange resin, followed by XRF analysis of Fe, Ni, Cu, Zn and Pb at μg l^-1 concentrations in aqueous samples. The operational parameters tested to maximise analyte recovery included flow rate, and the mass and chemical form of the resin. The method was tested with extracts from landfill soils and surface waters from a derelict basemetal mine. The method recovered Cu, Zn and Pb accurately, and Ni and Fe at concentrations satisfactory for screening purposes.