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.

Abstract

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) ([P6,6,6,14+]2[MnCl42-]) and aliquat tetrachloromanganate (II) ([Aliquat+]2[MnCl42-]) were employed and the optimized extraction conditions were comprised of 5mg of MIL ([P6,6,6,14+]2[MnCl42-]), 5μL of methanol (MeOH) as disperser solvent, and an extraction time of 90s at sample pH6. The analytical parameters of merit were determined under optimized conditions and very satisfactory results were achieved, with LODs of 2ngmL-1 for all analytes, determination coefficients (R2) 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 5ngmL-1) and interday precision (evaluated at 100ngmL-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.