Modified Silica Gels and Their Use for the Preconcentration of Trace Elements

This article presents the state-of-the-art of modified silica gels with different inorganic and organic chemicals and their use for the separation of trace elements from different sample matrices as well as their preconcentration. Different modification reactions, off-line and on-line preconcentration techniques and separation methods for the determination of trace elements have been presented in detail in this review. The advantages and disadvantages of the modified silica gels, design of modification reactions, choice of complexing agents, choice of eluents, limits of detection, preconcentration factors and analytical applications in different environmental samples using various spectrometric and chromatographic detection techniques have been discussed. These home-made materials allow analytes to be selectively extracted from complex matrices enabling them to be determined without matrix interferences and yielding improved detection limits.