Homogeneous liquid-liquid microextraction via flotation assistance for rapid and efficient determination of polycyclic aromatic hydrocarbons in water samples.

In this work, a rapid, simple and efficient homogeneous liquid-liquid microextraction via flotation assistance (HLLME-FA) method was developed based on applying low density organic solvents without no centrifugation. For the first time, a special extraction cell was designed to facilitate collection of the low-density solvent extraction in the determination of four polycyclic aromatic hydrocarbons (PAHs) in water samples followed by gas chromatography-flame ionization detector (GC-FID). The effect of different variables on the extraction efficiency was studied simultaneously using experimental design. The variables of interest in the HLLME-FA were selected as extraction and homogeneous solvent volumes, ionic strength and extraction time. Response surface methodology (RSM) was applied to investigate the optimum conditions of all the variables. Using optimized variables in the extraction process, for all target PAHs, the detection limits, the precisions and the linearity of the method were found in the range of 14-41 µg L(-1), 3.7-10.3% (RSD, n=3) and 50-1000 µg L(-1), respectively. The proposed method has been successfully applied to the analysis of four target PAHs in the water samples, and satisfactory results were obtained.

Determination of polycyclic aromatic hydrocarbons in soil samples using flotation-assisted homogeneous liquid-liquid microextraction.

In this study, flotation-assisted homogeneous liquid-liquid microextraction (FA-HLLME) was developed as a fast, simple, and efficient method for extraction of four polycyclic aromatic hydrocarbons (PAHs) in soil samples followed by gas chromatography-flame ionization detector (GC-FID) analysis. A special home-made extraction cell was designed to facilitate collection of the low-density extraction solvent without a need for centrifugation. In this method, PAHs were extracted from soil samples into methanol and water (1:1, v/v) using ultrasound in two steps followed by filtration as a clean-up step. The filtrate was added into the home-made extraction cell contained mixture of 1.0 mL methanol (homogenous solvent) and 150.0 µL toluene (extraction solvent). Using N(2) flotation, the dispersed extraction solvent was transferred to the surface of the mixture and was collected by means of a micro-syringe. Then, 2 µL of the collected organic solvent was injected into the GC-FID for subsequent analysis. Under optimal conditions, linearity of the method was in the range of 40-1000 µg kg(-1) soil (dry weight). The relative standard deviations in real samples varied from 5.9 to 15.2% (n=4). The proposed method was successfully applied to analyze the target PAHs in soil samples, and satisfactory results were obtained.