Determination of estrogens in environmental water samples using 1,3-dipentylimidazolium hexafluorophosphate ionic liquid as extraction solvent in dispersive liquid-liquid microextraction.
In this work, the potential of a symmetric dialkyl-substituted ionic liquid (IL), 1,3-dipenthylimidazolium hexafluorophosphate ([PPIm][PF6 ]), as extraction solvent in dispersive liquid-liquid microextraction (DLLME) has been studied for the analysis of a group of three natural (estriol, 17β-estradiol, and 17α-estradiol) and four synthetic (17α-ethynylestradiol, diethylstibestrol, dienestrol, and hexestrol) estrogenic compounds as well as one mycotoxin with estrogenic activity (zearalenone) in different types of water samples (Milli-Q, mineral, and wastewater). Separation, determination, and quantification were developed by HPLC-DAD and a fluorescence detector (FD) connected in series. Factors influencing the IL-DLLME procedure (sample pH, amount of IL, type and volume of disperser solvent, ionic strength, and assistance of vortex agitation) were investigated and optimized by means of a step-by-step approach. Once the optimum extraction conditions were established (10 mL of water at pH 8, 60 mg of [PPIm][PF6 ], 500 μL of ACN as disperser solvent and vortex agitation for 1 min), the calibration curves of the whole method (IL-DLLME-HPLC-DAD/FD) were obtained and precision and accuracy were evaluated. It was demonstrated that the developed methodology was repeatable, accurate, and selective with limits of detection in the 0.30-0.57 μg/L and 13.8-37.1 μg/L range for FD and DAD, respectively. Relative recovery values were higher than 85% for the different types of water samples and the Student's t test demonstrated that there were not significant differences between the added and the found concentration.
Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Química, Universidad de La Laguna (ULL), La Laguna (Tenerife), Spain.
Bárbara
B
Socas-Rodríguez
Javier
J
Hernández-Borges
María
M
Asensio-Ramos
Antonio V
AV
Herrera-Herrera
Jose A
JA
Palenzuela
Miguel Ángel
MÁ
Rodríguez-Delgado
D002851:Chromatography, High Pressure Liquid; D004967:Estrogens / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000737:chemistry*; D057230:Limit of Detection; D016014:Linear Models; D059627:Liquid Phase Microextraction / Q000379:methods*; D015203:Reproducibility of Results; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification
D004967:Estrogens; D007093:Imidazoles; D014874:Water Pollutants, Chemical
Dispersive liquid-phase microextraction; Estrogens; HPLC; Ionic liquid; Mycotoxin