UTILIZATION OF CLOUD-POINT EXTRACTION COMBINED WITH MOLECULAR ABSORPTION SPECTROSCOPY FOR DETERMINATION OF ZINC FROM VEGETABLES TAKEN AT DALAT MARKETS

Abstract

A cloud-point extraction technique combined with atomic absorption spectroscopy was applied to determine amount of zinc ion from the selected commercial vegetables in Dalat. In this work, 1-(2-pyridylazo)-2- naphtol (PAN) and Triton X-100 were used as main chemical reagents. A pink-complexation was obtained via a reaction of Zn(II) and PAN at pH 8.5. This solution posed the maximum absorption wavelength of 545nm. Under the optimum conditions, the limit of detection (LOD) and relative standard deviation (RSD) of this method were 0.12 mg/kg and 0.13% respectively, while the recovery is 89.3%.

Keywords: Clould-point extraction, plant analysis, zinc, spectrophotometry.