Use of Ionic Liquids for Liquid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons

Abstract

can be formed and survive for a longer extraction time; therefore, a much higher enrichment factor for PAHs can be reached. For low-volatility PAHs, direct-immersion LPME provides higher enrichment factors than that of headspace LPME. However, the enrichment factor obtained by headspace LPME was almost 3-fold of that by direct-immersion LPME in a 30-min extraction of the most volatile PAH, naphthalene. For 30-min directionimmersion LPME of EPA priority PAHs, the enrichment factor, correlation coefficient (R 2 ), and reproducibility (RSD, n ) 5) were in the range of 42-166, 0.9169-0.9976, and 2.8-12%, respectively. Considering that IL can be easily prepared from relatively inexpensive materials and tuned by combination of different anions and cations for task-specific extraction of analytes from various solvent media, this proposed method should have great potentiality in sample preparation. Furthermore, the nonvolatility of IL makes it potentially useful for headspace LPME of volatile analytes.Ionic liquids (IL) are ionic media resulting from combinations of organic cations and various anions. They may be liquids at room temperature. Their use as novel solvent systems for organic synthesis and catalysis has received a good deal of attention. 1 IL have several unique properties that make them useful in a variety of chemical processes. For example, they have no effective vapor pressure, the viscosity and the miscibility in water and other organic solvents can be tuned by changing the combination of different anions and cations of IL, and the preparation is easy from relatively inexpensive materials. 1,2 As a result of these properties, IL is emerging as an alternative recyclable medium for separation. Recently, IL were considered as attractive water-immiscible phases in liquid-liquid extraction. 3-5 IL were also used in organic solvent-supercritical CO 2 biphasic extractions 6-8 and in pervaporation. 4,9 By using two typical IL, 1-butyl-3-methylimidazolium hexafluorophosphate G.

Ionic liquids in sample preparation

“…Extraction of organic contaminants Our group [38] provided the first example of the use of ILs as solvents for liquid-phase microextraction (LPME) of polycyclic aromatic hydrocarbons (PAHs) from water. A 3 μl drop of [C 8 MIM][PF 6 ] suspended on the tip of a microsyringe was employed for immersed or headspace extraction of the analytes from water samples for 30 min, followed by direct injection into the liquid chromatography system for determination.…”

Cyclodextrin-ionic liquid polyurethanes for application in drinking water treatment

“…Ferreira et al (2000) reported that the forces of attraction between the cation and the anion are not sufficiently strong enough to hold them together as solids at ambient temperatures hence it is possible, by proper choice of starting material, to synthesise ionic liquids that are liquid at or below room temperature. ILs possess unique physical properties such as negligible vapour pressure, an ability to dissolve a wide range of organic and inorganic material, high thermal stability (for example, some ILs are liquid at 400°C, while others are liquid at -96°C) as well as variable viscosity and miscibility with water and other organic solvents (Liu et al, 2003;Liu et al, 2005;Welton, 1999). However, the most important property of ionic liquids that has been exploited in this study is their ability to extract metals from aqueous media (Cruz, 2000;Liu et al, 2005).…”

“…The three most commonly known CDs contain 6 (α), 7 (β) and 8 (γ) glucose units which are linked together by α-(1,4) linkages (Bender and Komiyana, 1978). Liu et al (2003) reported that CDs have a non-polar cavity which provides a micro-environment for the encapsulation of non-polar, low molecular weight compounds (formation of an inclusion complex) (Scheme 1).…”

Tris(pentafluoroethyl)trifluorophosphate-basd ionic liquids as advantageous solid-phase micro-extraction coatings for the extraction of organophosphate esters in environmental waters

“…The unique properties of ionic liquids (ILs) like high stability, negligible vapor pressure, low melting points and moderate dissolvability of organic compounds make them ideal candidates for numerous micro-extraction approaches solvents [26][27][28][29][30] or sorbent coatings [31][32][33]. To our knowledge, however, there are only two papers on the development of IL-based SPME fibers for determination of OPEs [31,34].…”