Application of deep eutectic solvent based magnetic colloidal gel for dispersive solid phase extraction of ultra-trace amounts of some nitroaromatic compounds in water samples

Abstract

In this work, colloidal gel of magnetic carbon nanotube and deep eutectic solvent was prepared and used in developing a fast and efficient dispersive solid phase extraction method for enrichment of ultra-trace amounts of nitroaromatic explosives in water samples. In this colloidal gel, deep eutectic solvent is compatible with gas chromatography and acts simultaneously as both carrier and stabilizer for magnetic nanotubes. In this method, nanofluid was dispersed in solution and a dark cloudy suspension was formed which was stable against sedimentation. The extraction efficiency was improved and the extraction time was shortened with no need to shake the sample solution manually or use the external means. A face centered, central composite design was used for efficient optimization of main variables in the extraction procedure. Under the optimized conditions, the limit of detection and enrichment factor were in the range of 0.8–12.4ngL−1 and 267–415, respectively. The relative standard deviations were between 4.6% and 8.5% (n=6). Method validation was performed by both spiking–recovery method and comparison of results with other methods. The method followed by gas chromatography with micro-electron capture detector (GC-μECD), was successfully applied for determination of nitroaromatic explosives in water samples.