<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Quantitative thin layer chromatographic study of Al³⁺ in geological samples</span>

Abstract

A facile and sensitive quantitative visual analytical method has been developed for the determination of Al³⁺ in geological samples. The alumina (Al₂O₃) content in gibbsitic bauxite and related samples of geological origin is extracted in triple acidic medium. The sample solutions are purified and then subjected to quantitative thin layer chromatography (TLC) analysis. Combination of plain silica gel H and dilute aqueous solution of aluminon (0.005-0.50%) has been identified as the best chromatographic systems for the selective detection of Al³⁺. The important chromatographic parameters such as sample composition, <i>p</i>H effect, nature of adsorbent and mobile phase composition as well as detection limit are optimized in terms of spot size, colour stability and resolution of Al³⁺. The TLC chromatograms of Al³⁺ are quantitatively assessed by scanning densitometry and digital image analysis. Analytical potential of the optical quantitative methods have been verified for the quantitative TLC assessment of Al³⁺ in bauxite, soil, rock and aluminium spent potlining (SPL) samples with respect to the analogous wet analysis. Repeatability and reproducibility of the method are also evaluated under the optimized experimental conditions such as sample concentration, components and <i>p</i>H, slurry volume and layer thickness.