Headspace single drop microextraction versus dispersive liquid-liquid microextraction using magnetic ionic liquid extraction solvents

Abstract

A headspace single drop microextraction (HS-SDME) method and a dispersive liquid-liquid microextraction (DLLME) method were developed using two tetrachloromanganate ([MnCl])-based magnetic ionic liquids (MIL) as extraction solvents for the determination of twelve aromatic compounds, including four polyaromatic hydrocarbons, by reversed phase high-performance liquid chromatography (HPLC). The analytical performance of the developed HS-SDME method was compared to the DLLME approach employing the same MILs. In the HS-SDME approach, the magnetic field generated by the magnet was exploited to suspend the MIL solvent from the tip of a rod magnet. The utilization of MILs in HS-SDME resulted in a highly stable microdroplet under elevated temperatures and long extraction times, overcoming a common challenge encountered in traditional SDME approaches of droplet instability. The low UV absorbance of the [MnCl]-based MILs permitted direct analysis of the analyte enriched extraction solvent by HPLC. In HS-SDME, the effects of ionic strength of the sample solution, temperature of the extraction system, extraction time, stir rate, and headspace volume on extraction efficiencies were examined. Coefficients of determination (R) ranged from 0.994 to 0.999 and limits of detection (LODs) varied from 0.04 to 1.0μgL with relative recoveries from lake water ranging from 70.2% to 109.6%. For the DLLME method, parameters including disperser solvent type and volume, ionic strength of the sample solution, mass of extraction solvent, and extraction time were studied and optimized. Coefficients of determination for the DLLME method varied from 0.997 to 0.999 with LODs ranging from 0.05 to 1.0μgL. Relative recoveries from lake water samples ranged from 68.7% to 104.5%. Overall, the DLLME approach permitted faster extraction times and higher enrichment factors for analytes with low vapor pressure whereas the HS-SDME approach exhibited better extraction efficiencies for analytes with relatively higher vapor pressure.

Investigating the effect of ligand and cation on the properties of metal fluorinated acetylacetonate based magnetic ionic liquids

“…Higher viscosity MILs have advantages in applications that require highly mechanically stable liquids. 29 Yoshida et al found that longer alkyl chain substituents in imidazolium-based MILs resulted in higher viscosity. 28 Other approaches for modulating the viscosity include mixing two components of different viscosity to generate mixtures that contain lower viscosity than the individual components themselves.…”

Ionic liquids: solvents and sorbents in sample preparation

“…In this study, the MIL was dispersed using acetone in combination with vortexing and subsequently collected using an external magnet. PAHs were back-extracted from the MIL using n-hexane, reconstituted in acetonitrile, and analyzed by HPLC with fluorescence detection to reveal that the [N 8 [98]. Relative to MIL-HS-SDME, MIL-DLLME required shorter extraction times and exhibited higher enrichment factors for nonvolatile compounds like acetophenone, 2-chloroaniline, and phenanthrene.…”

“…Furthermore, the magnetic rod also provides greater droplet stability relative to conventional syringes, thereby granting access to prolonged extraction times at faster stir rates. An and coworkers were the first to demonstrate MIL-based HS-SDME for the determination of aromatic compounds and PAHs [98]. By employing a rod magnet in the SDME method, it was possible to perform 60 min extractions at 400 or 800 rpm using the [P 6,6,6 4 2− ] MILs, respectively.…”

Systematic investigation for extraction and separation of polyphenols in tea leaves by magnetic ionic liquids

“…proposed a microextraction method for analyzing acidic pharmaceuticals and phenolic compounds using MIL, which was recovered by an external magnetic field to avoid the use of volatile organic solvents or adsorbents. An et al . successfully used MIL as the extract solvent for the analysis of polycyclic aromatic hydrocarbons.…”

“…In the separation field, Chatzimitakos et al 9 proposed a microextraction method for analyzing acidic pharmaceuticals and phenolic compounds using MIL, 9 which was recovered by an external magnetic field to avoid the use of volatile organic solvents or adsorbents. An et al 10 successfully used MIL as the extract solvent for the analysis of polycyclic aromatic hydrocarbons. Akbari et al 11 and Wang et al 12 also used MIL in the extraction and achieved good separation by a magnetic field.…”