Central composite design for the enzymatic detection of arsenic (III) in aqueous solution from vegetable -waste

Abstract

Urease has been used for the quantitative estimation of As (III) in water. For the parametric optimization of this process Response Surface Methodology was used with the help of two-level-two-full factorial (22), Central Composite Design. Regression coefficient, regression equation and Analysis of Variance (ANOVA) was obtained using MINITAB® 15 software. Predicted values obtained were close to experimental value indicating suitability of model. The 3D Response Surface Plot and Isoresponse Contour Plot were helpful to predict the results by performing only limited set of experiments. Enzyme Urease was extracted from the discarded seeds of pumpkin. It was purified to apparent homogeneity (5.2 fold) by heat treatment at 48±0.1 °C and gel filtration through Sephadex G-200. Effect of As(III) on the activity of homogeneous enzyme preparation (Sp Activity 353 U/mg protein, A 280/A260 = 1.12) was investigated. Inhibition caused by As (III) was non-competitive, irreversible and biphasic. © 2008 Springer-Verlag.