Separation of deltametrin and cypermethrin from agricultural soil and water samples using dispersive liquid–liquidmicroextraction method based on solidification of floating organic drop combined with gas chromatography-mass spectrometry

In this research study, the rapid and simple method of dispersive liquid–liquid microextraction method based on solidification of floating organic drop (DLLME-SFO) was used for simultaneous separation/preconcentration of deltametrin and cypermethrin from agricultural soil and water samples. The analytes were determined by gas chromatography-mass spectrometry. The influential parameters of DLLMESFO including type and volume of extraction solvent type, type and volume of dispersive solvent, sample volume were optimized. A mixture of 1 mL methanol as dispersive solvent, 10 μL 2-dodecanol was rapidly injected into the 10 mL aqueous solution. A cloudy solution was formed. The solution was centrifuged for 3 min at 5500 rpm. The test tube was then cooled in an ice bath. After 5 min the 2-dodecanol solidified and was then transferred to a conical vial; it melted quickly at room temperature and 1 μL of it was injected into a gas chromatograph-mass spectrometry for analysis. The limits of detection (LOD) of 0.005 and 0.008 μg L−1 were obtained for deltametrin and cypermethrin respectively. The linear range of 0.01-500 μg L−1 with a coefficient (r2) of 0.999 was obtained for both analytes. The proposed method was successfully applied for determination of trace amount of deltametrin and cypermethrin in agricultural soil and water samples.

Keywords:

dispersive liquid–liquid microextraction , solidification of floating organic drop , pesticides