Magnetic ionic liquids as versatile extraction phases for the rapid determination of estrogens in human urine by dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography-diode array detection.

In this study, a rapid and straightforward approach based on magnetic ionic liquids (MIL) as extraction phases and dispersive liquid-liquid microextraction (DLLME) was developed to analyze the hormones estriol, 17-β-estradiol, 17-α-ethynylestradiol, and estrone in human urine samples. This is the first report of an application of manganese-based MILs compatible with HPLC to extract compounds of biological interest from urine samples. The hydrophobic MILs trihexyltetradecylphosphonium tetrachloromanganate (II) ([P _6,6,6,14 ⁺ ] ₂ [MnCl ₄ ^2- ]) and aliquat tetrachloromanganate (II) ([Aliquat ⁺ ] ₂ [MnCl ₄ ^2- ]) were employed and the optimized extraction conditions were comprised of 5 mg of MIL ([P _6,6,6,14 ⁺ ] ₂ [MnCl ₄ ^2- ]), 5 μL of methanol (MeOH) as disperser solvent, and an extraction time of 90 s at sample pH 6. The analytical parameters of merit were determined under optimized conditions and very satisfactory results were achieved, with LODs of 2 ng mL ^-1 for all analytes, determination coefficients (R ² ) ranging from 0.9949 for 17-β-estradiol to 0.9998 for estrone. In addition, good results of method precision were achieved with the intraday (n = 3) varying from 4.7% for 17-β-estradiol to 19.5% for estriol (both at 5 ng mL ^-1 ) and interday precision (evaluated at 100 ng mL ^-1 ) ranging from 11.4% for estrone to 17.7% for 17-α-ethynylestradiol and analyte relative recovery evaluated in three real samples ranged from 67.5 to 115.6%. The proposed DLLME/MIL-based approach allowed for a reliable, environmentally friendly and high-throughput methodology with no need for a centrifugation step. Graphical abstract An overview of the rapid and straightforward extraction procedure using DLLME/MIL-based approach.