A novel polythiophene - ionic liquid modified clay composite solid phase microextraction fiber: Preparation, characterization and application to pesticide analysis.

This report comprises the novel usage of polythiophene - ionic liquid modified clay surfaces for solid phase microextraction (SPME) fiber production to improve the analysis of pesticides in fruit juice samples. Montmorillonite (Mmt) clay intercalated with ionic liquids (IL) was co-deposited with polythiophene (PTh) polymer coated electrochemically on an SPME fiber. The surface of the fibers were characterized by using scanning electron microscopy (SEM). Operational parameters effecting the extraction efficiency namely; the sample volume and pH, adsorption temperature and time, desorption temperature and time, stirring rate and salt amount were optimized. In order to reveal the major effects, these eight factors were selected and Plackett-Burman Design was constructed. The significant parameters detected; adsorption and temperature along with the stirring rate, were further investigated by Box-Behnken design. Under optimized conditions, calibration graphs were plotted and detection limits were calculated in the range of 0.002-0.667ng mL(-1). Relative standard deviations were no higher than 18%. Overall results have indicated that this novel PTh-IL-Mmt SPME surface developed by the aid of electrochemical deposition could offer a selective and sensitive head space analysis for the selected pesticide residues.

Ionic liquid intercalated clay sorbents for micro solid phase extraction of steroid hormones from water samples with analysis by liquid chromatography-tandem mass spectrometry.

Clay material plays an important role in the transport and retention of many compounds in the soil, therefore, clay based sorbents are promising alternatives for selective sorption of organic pollutants. In the present work, different chain length ionic liquids (ILs) namely, 1-methyl-3-octyl-imidazolium bromide, 1-methyl-3-undecyl-imidazolium bromide and 1-methyl-3-octadecyl-imidazolium bromide were intercalated in the galleries of montmorillonite (MMT) clay. Then, this novel nanofiller surface was utilized in micro extraction of estrogenic hormones for the first time. A fast procedure where sonication-assisted emulsification microextraction combined with vortex assisted micro-solid phase extraction (µ-SPE) was developed for the LC-MS/MS analysis of estrone (E1), 17ß-estradiol (E2), estriol (E3) and ethynylestradiol (EE2). The parameters related to the µ-SPE procedure namely; pH, sorbent amount, extraction solvent type and volume, sonication and vortex time, sample volume and salt effect on the extraction efficiency were screened by applying Plackett-Burmann design. The selected parameters were then optimized by using Box-Behnken design. The method was validated for the determination of estrogenic hormone residues in river water samples. Linear calibration plots were obtained for all hormones whose regression coefficients were larger than 0.98. RSD values were found less than 10% for three levels of concentration. LOD levels were calculated as; 0.012, 0.062, 0.018 and 0.693 ng L(-1) for E1, E2, E3 and EE2, respectively. Recovery values were calculated in the range of 86.9-97.7%. Considering large sample volumes required for attaining low limits of these hormones, present method provides an ease for analyst as 10 mL of the sample is adequate for achieving the same sensitivity.