Nano polypyrrole-coated magnetic solid phase extraction followed by dispersive liquid phase microextraction for trace determination of megestrol acetate and levonorgestrel

• Magnetic solid phase extraction was followed by dispersive liquid phase microextraction.
• Sedimented phase was separated by filtration based phase separation.
• The separated phase was eluted and transferred to HPLC-UV for separation and analysis.
• Method was applied for detection of megestrol and levonorgestrel in biological samples.
• Under the optimal conditions, a linear range from 0.05 to 50 ng mL−1 was obtained.

The aim of the present work is combination of the advantages of magnetic solid phase extraction (MSPE) and dispersive liquid phase microextraction (DLLME) followed by filtration-based phase separation. A new pretreatment method was developed for trace determination of megestrol acetate and levonorgestrel by liquid chromatography/ultraviolet detection in biological and wastewater samples. After magnetic solid phase extraction, the eluent of MSPE was used as the disperser solvent for DLLME. Emulsion resulted from DLLME procedure was passed through the in-line filter for phase separation. Finally the retained analytes in the filter was washed with mobile phase of liquid chromatography and transferred to the column for separation. This approach offers the preconcentration factors of 3680 and 3750 for megestrol acetate and levonorgestrel, respectively. This guarantees determination of the organic compounds at trace levels. The important parameters influencing the extraction efficiency were studied and optimized. Under the optimal extraction conditions, a linear range of 0.05–50 ng mL−1 (R2 > 0.998) and limit of detection of 0.03 ng mL−1 were obtained for megestrol acetate and levonorgestrel. Under optimal conditions, the method was successfully applied for determination of target analytes in urine and wastewater samples and satisfactory results were obtained (RSDs < 6.8%).

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