DETERMINATION OF MOLYBDENUM IN WATER SAMPLES BY SPECTROPHOTOMETRY USING Al2O3/TiO2 NANOCOMPOSITE WITH CLOUD POINT EXTRACTION TECHNIQUE

Abstract

The Al₂O₃/TiO₂ nanocomposite was applied as a new solid phase adsorbent for preconcentration of Molybdenum before determination by an UV-Vis spectrophotometer with cloud point extraction technique. The solid-phase extraction conditions as pH, the mass of sorbent, contact time, stirring speed, and the desorption condition were investigated. Molybdenum ions were determined based on its catalytic effect on the oxidation of 1-amino-2- naphthol-4-sulfonic acid with H₂O₂ and the solution was then extracted by cloud point extraction and spectrophotometric measurement at 465 nm. The cloud point extraction conditions as pH, Triton X-100, salt amount, and extraction temperature were investigated, sequently. The cloud point extraction efficiency was highest with 4 mL of Triton X-100 60%, 2.5 g of salt NaCl; pH 5 at 40⁰C. Under optimal cloud point extraction, the linear calibration graph was in the range of 0.2–2.5 µg/L (r² = 0.995) with a quantitative limit of 0.1676 µg/L. The relative standard deviation for five measurements of 2 µg/L of Mo (VI) was 3.37%. The method was applied to the determination of Molybdenum in water samples.