Determination of Silicones in Vegetable Oils by Nonflame Atomic Absorption Spectrophotometry

✍ Scribed by Kundu, M. K.

• Publisher: John Wiley and Sons
• Year: 1977
• Weight: 405 KB
• Volume: 79
• Category: Article
• ISSN: 0931-5985
• DOI: 10.1002/lipi.19770790409

✦ Synopsis

Abstract

The determination of silicone in oil was based upon conversion of the oil into water‐soluble form (Na/K‐Soap) in a teflon tube, extraction of the water‐insoluble, solvent‐soluble silicones with petroleum ether, and determination of the silicones in some suitable organic solvent by nonflame atomic absorption spectrometry (AAS). (An aliquot of this extract might be used to chromatographically detect silicones originally present in the oil in a very low concentration). The standard deviation and the per cent relative standard deviation data for silicone in oil at ca. 2 ppm level were 0.41 and 25.20 respectively. The contamination of silica from the reagents employed can be virtually eliminated. The success of the method lies principally in the purity of the alkali employed. Direct determination of the silicones by flame‐ or nonflame AAS was not satisfactory at low concentrations. Apart from the volatility of the silicones, the presence of oil appeared to seriously suppress the sensitivity level of determination. Digestion of the silicone containing oil with HNO~3~‐HClO~4~‐H~2~SO~4~ apparently improved the sensitivity level but the advantages gained were mostly offset by the contamination of silicates from the acid reagents employed.