Vortex-assisted dispersive micro-solid phase extraction based on nanostructured imprinted polymer: A comparison study between spectrophotometric and solution scanometric techniques

Abstract

In the present work, methyl red molecularly imprinted polymeric (MR-MIP) nanostructure was synthesized using the precipitation polymerizations for the separation of MR dye from aqueous media. The as-prepared MIP was characterized using colorimetry, infrared (IR) spectroscopy, and scanning electron microscopy (SEM). In addition, vortex-assisted dispersive micro-solid phase extraction (VAD-µSPE) based on MIP nanostructure was accomplished as a simple and efficient method for selective preconcentration of low amounts of MR from aqueous solutions. The effects of important parameters such as pH, adsorbent dose, eluent volume, and vortex adsorption–desorption time on the extraction efficiency were investigated. Two techniques including UV–Vis absorption spectroscopy and solution scanometry were applied for the analysis of MR content, comparatively. In spectrophotometric determination, the highest recovery was observed at pH 3.5 after 5 and 3 min of vortex time in the adsorption and desorption steps. The preconcentration factor of 75 and a wide linear concentration range (0.010 and 2.0 mg.L−1; R2 = 0.996) and low detection limit (LOD = 5.0 µg.L−1) with an acceptable precision (RSD = 3.4 %) was observed, too. Under optimum conditions in scanometric determination, a high preconcentration factor (i.e. 500) and similar linearity (0.010–2.0 mg.L−1; R2 = 0.989) and a low LOD of 3.1 µg.L−1, with the relative standard deviation of 1.4% was observed. Both techniques were used for MR recovery from various aqueous samples, successfully.