Silicon speciation by hyphenated techniques for environmental, biological and industrial issues: A review

Abstract

Silicon speciation in environmental, biological and industrial matrices is of considerable importance due to its wide use in many consumer and personal care products and industry. In addition, the entry of silicones in various compartments like wastes, soils, air and water highlights the need to perform exposure studies, toxicological surveys and to measure negative effects. Due to possible contamination and trace level presence of silicon compounds, challenges to determination, identification and quantification are presented. The principal species of concern include siloxanes, silanols, silanediols and silanes. State of the art of analytical methods for total silicon determination and silicon speciation are established. Atomic spectroscopic methods are mainly used to measure total Si at trace concentration levels. On the opposite, hyphenated techniques are performed for Si speciation. Particular attention is paid to chromatographic methods coupled to sensitive and selective detectors (MS, AED and ICP) allowing structural information. Liquid and gas chromatography emerge as the most widespread separation techniques. However, other procedures such as MS, NMR, IR and XRF enable a better knowledge of these species. The potential and limitations of hyphenated techniques are highlighted, particularly concerning sensitivity and selectivity. Furthermore, potential sources of contamination and analytical artifacts in silicon determination are reviewed.