Solid-Phase Hydride Generation of Silane for Determination of Silicate by ICP-AES

Abstract

A sample introduction method based on in situ solid-phase SiH₄ generation for ICP-AES has been proposed for the determination of silicate. The hydride generation procedure is as follows: An aqueous sample solution is dried on a sample cuvette, and LiAlH₄ solution is added onto the dehydrated sample and is dried again. The cuvette is then located on a tungsten boat furnace. Silane species are generated by heating the cuvette at 700°C, with the species introduced directly into the ICP to measure the atomic emission of Si. The amount of LiAlH₄, the reaction temperature, and the flow rate of the Ar carrier gas were optimized. The calibration curve was linear up to at least 100 ng of Si(IV) and the detection limit (signal-to-noise ratio of 3) was 0.03 ng. The relative standard deviation for 10 replicate measurements of 1.0 ng of Si(IV) was 2.7%. This method was applied to the determination of Si in river water with satisfactory results.