Determination of Trace Elements Using UV–Vis Spectrophotometry

Abstract

The popularity of UV–vis spectrophotometric methods in trace element analysis arises from their modest apparative requirements, possibility of use by a moderately trained analyst, at least in developing countries, an adequate sensitivity and an accuracy often as good as, if not better than, that of other methods in the same range. The sensitivity may further be enhanced to determine the elements at the abundance level in geological samples by developing newer spectrophotometric methods with higher sensitivity and higher selectivity, by synthesizing suitable organic reagents with active donor sites/functional groups capable of acting as chelating ligands with the metals, optimizing the various parameters involved in the formation of a metal–ligand complex by chemical amplification, formation of ternary complexes, sensitization of a metal–ligand reaction by a surfactant or by utilizing the catalytic effect of the microconstituent in a colour formation reaction (catalytic/kinetic methods), or extractive preparation or a suitable combination of these whenever feasible, higher sensitivity being the most important desideratum even at the cost of reproducibility and stability (within limits) especially while determining the minute amounts of the trace elements.