Analytical perspective. Solid phase techniques for the preconcentration of trace metals from natural waters

Abstract

The preconcentration of trace metals is often necessary for their determination in natural waters. Solid phase techniques are now widely used for this purpose, either in an off-line batch mode or, increasingly commonly, in an on-line capacity in conjunction with flow injection analysis. Trace metals are typically preconcentrated on-line by injection of microlitre to millilitre sample volumes into a suitable buffered carrier stream and are eluted to the detector by injection of a smaller volume of eluting material, most commonly a mineral acid. This review classifies the various solid phases used (iminodiacetate, quinolin-8-ol, dithiocarbamate and others) and tabulates the applications in terms of analyte, sample matrix, solid phase, detection system and reported detection limits. Alternative approaches, such as the use of immobilized algae, are also reported.