Ionic liquids (ILs) comprise mostly of organic salts with negligible vapor pressure and low flammability that are proposed as replacements for volatile solvents. ILs have been promoted as "green" solvents and widely investigated for their various applications. Although the utility of these chemicals is unquestionable, their toxic effects have attracted great attention. In order to manage their potential hazards and design environmentally benign ILs, understanding their environmental behavior, fate and effects is important. In this review, environmentally relevant issues of ILs, including their environmental application, environmental behavior and toxicity are addressed. In addition, also presented are the influence of ILs on the environmental fate and toxicity of other coexisting contaminants, important routes for designing nontoxic ILs and the techniques that might be adopted for the removal of ILs.
Advances in analytical chemistry using the unique properties of ionic liquidsZhi-qiang Tan, Jing-fu Liu, Long Pang Ionic liquids (ILs) are regarded as non-molecular solvents, as they are composed entirely of cations and anions. ILs possess several excellent unique properties (e.g., low volatility, high thermal stability, specific electrochemical characteristics, easy design, tunable viscosity, and miscibility with water or organic solvents). These properties make ILs attractive candidates for various analytical applications, the number of publications on which has increased exponentially in the past decade.This article presents an overview of representative applications of ILs in advances in analytical chemistry that benefited from the unique properties of ILs, including the development achieved by using ILs as extraction solvents, dissolution solvents and separation media. ª
a b s t r a c tA novel approach was developed for the fabrication of solid-phase microextraction (SPME) fiber by coating stainless steel fiber with a polymeric ionic liquid (PIL) through covalent bond. The stainless steel fiber was sequentially coated with a gold film by replacement reaction between Fe and Au when immerged in chloroauric acid, assembled with a monolayer of 3-(mercaptopropyl) triethoxysilane on the gold layer through the Au-S bond, and coated with a silica layer by the hydrolysis and polycondensation reaction of the surface-bonded siloxane moieties and the active silicate solution. Then, 1-vinyl-3-(3-triethoxysilylpropyl)-4,5-dihydroimidazolium chloride ionic liquid was anchored on the silica layer by covalent bond, and the PIL film was further formed by free radical copolymerization between 1-vinyl-3-(3-triethoxysilylpropyl)-4,5-dihydroimidazdium and vinyl-substituted imidazolium with azobisisobutyronitrile (AIBN) as initiator. Parameters influencing the preparation of PIL fiber were optimized, and the developed SPME fiber has a coating thickness of ∼20 m with good thermal stability and long lifetime. The performance of the PIL fiber was evaluated by analysis of polycyclic aromatic hydrocarbons (PAHs) in water samples. The developed PIL fiber showed good linearity between 0.5 and 20 g l −1 with regression coefficient in the range of 0.963-0.999, detection limit ranging from 0.05 to 0.25 g l −1 , and relative standard deviation of 9.2-29% (n = 7). This developed PIL fiber exhibited comparable analytical performance to commercial 7 m thickness PDMS fiber in the extraction of PAHs. The spiked recoveries for three real water samples at 0.5-5 g l −1 levels were 49.6-111% for the PIL fiber and 40.8-103% for the commercial PDMS fiber.
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