Response Surface Methodology of Pre-Concentration of Chorophenols from Seawater Samples by Molecularly Imprinted Stir Bar Sorptive Extraction Combined with HPLC: Box-Behnken Design.

Abstract

A novel molecularly imprinted polymer coated stir bar was prepared using 2-chlorophenol (2-CP) as template molecule and used for selective extraction of phenolic compounds including chlorophenols (CPs) directly from seawater samples. Various parameters affecting extraction have been evaluated using one variable-at-a-time and Box-Behnken design. A three-level Box-Behnken experimental design by six factors, which combined the response surface methodology, was used to optimize the selective extraction of the CPs. Six independent variables, including the absorption and desorption times (ranging from 15 to 25 min), stirring speed (ranging from 550 to 650 rpm), pH of solution (ranging from 4.0 to 6.0), amount of NaCl (ranging from 0.30 to 0.40 mol/L) and temperature of extraction process (ranging from 40 to 50°C) were coded as A, B, C, D, E and F at three various levels (-1, 0 and 1). Under the optimum conditions, the detection limits calculated were 0.17, 0.33 and 0.38 μg/L, respectively, for 2-CP, 2,4-dichlorophenol and 2,4,6-trichlorophenol. The linear ranges of method were 1.0-100.0 μg/L for all CPs studied. This method was employed for the direct extraction and determination of three CPs in seawater samples.