Silicon determination by inductively coupled plasma atomic emission spectrometry after generation of volatile silicon tetrafluoride

A method for the determination of silicon by inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The procedure is based on a discontinuous generation of volatile silicon tetrafluoride in concentrated sulphuric acid medium after injecting 125 mu l of 0.1%, w/v sodium fluoride solution into 100 mu l of the sample. The gaseous silicon tetrafluoride is fed directly into the ICP torch by a flow of 250 ml min(-1) Ar carrier gas. The calibration curve was linear up to al least 100 mu g ml(-1) of Si(IV) and the absolute detection limit was 9.8 ng working with a solution volume of 100 mu l. The relative standard deviation for six measurements of 10 mu g ml(-1) of Si(IV) was 2.32%. The method was applied to the determination of silicon in water and iron ores. (C) 1998 Elsevier Science B.V.