Application of nanostructured supramolecular solvent based on C12mimBr ionic liquid surfactant to direct extraction of some chlorophenols in soil and rice samples

Abstract

In the proposed research, ionic liquid surfactant (C12-mimBr)-based nanostructured supramolecular solvent (IL-SUPRAS) was applied for direct extraction and preconcentration of three chlorophenols (CPs) in soil and rice samples before using gas chromatography-flame ionization detection (GC-FID) analysis. Mainly for extraction of analyte from a solid sample, an initial extraction step is performed using harmful organic solvents. Then, after evaporation of those solvents, the secondary extraction method is applied. The purpose of this research is direct extraction of some analytes from solid samples without performing the initial extraction step and using an adverse organic solvent. At first, IL-SUPRAS aggregation was prepared in a water solution. After that, an appropriate amount of it was introduced to the Eppendorf vial containing the solid sample. In the next step, to effectively extract the analytes from samples to the SUPRAS phase, the Eppendorf vial was vortexed and centrifuged, respectively. Finally, to prevent the entrance of the SUPRAS phase into the GC instrument, a back extraction step of the analytes was performed. The influence of effective parameters (i.e., pH of sample solution, vortex time, centrifuge time, and volume of THF) on the extraction procedure was investigated. Under optimum experimental conditions, the enrichment factors were obtained in the reasonable range of 103.2–134.6. The calibration curves also were linear in the range of 1.0–2000 µg L-1 with coefficients of determination (R2) more than 0.9962 for all three analytes. Limits of detection (S/N = 3) of 0.3–0.7 µg L-1, thelimits of quantification (LOQ) of 0.99–2.1 µg L-1, the relative standard deviations (RSDs %) composed of inter-day RSD (7.6–8.7) and intra-day RSD (6.3–7.6),and relative recoveries in the range of 77.4–93.6 % were obtained. The proposed method (IL-SUPRAS-DME) was successfully applied, for direct and fast extraction of CPs analytes in soil and rice samples.