Browsing by Author "Vyavaharkar, Kashmira"

Ionic liquids (ILs), also known as molten salts or fused salts, are a unique class of non-volatile and low-melting solvents which are composed entirely of cations and anions. These salts are liquid at room-temperature or below 100°C, thus the term 'room-temperature ionic liquids' (RTIL). Ionic liquids are known to possess some very intriguing properties such as negligible vapour pressure, remarkable thermal and electrochemical stability, non-flammability and high ionic conductivity. They have notable feature of tunability, due to which they are commonly known as 'designer solvents'. Interest in the different aspects and application of ILs in diverse fields has increased rapidly in the past few years which is pretty evident from the increasing number of research publications. The main aim of this thesis is to study the applicability of phosphonium-based ionic liquids in the field of analytical chemistry, focusing on extraction techniques. In this work, novel phosphonium-based ILs are synthesized by maintaining a common phosphonium-based cation and varying the counter-anion with carboxylate ones. Furthermore, these prepared ILs were tested for their critical micelle concentrations by using capillary electrophoresis as the mode of determination. In this work, different prospects of the use of phosphonium ILs in traditional as well as modern extraction techniques have been studied. This sub-set of ionic liquids has been the favourite choice of researchers in liquid-liquid extraction as a co-solvent as replacements of traditional volatile organic solvents. Similarly, in various microextraction techniques, phosphonium ionic liquids have been favored as a co-solvent or an ion-pair reagent while in the membrane extraction processes, they have been used as carrier in the transport of metal ions. Moreover, different parameters affecting the extraction process, for example, the effect of alkyl chain length of the ionic liquid cation and anion, branching, or even the effect of temperature have been studied. Phosphonium based ionic liquids not only find their place in the extraction of metal ions, phenolic compounds and radiochemical elements. ILs with desirable properties can be obtained by playing with the design of cation and anion of a particular IL. Taking advantage of this unique feature, many researchers have synthesized ILs to test their applicability in the extraction methods with remarkable extraction efficiencies. In the experimental section of this work, the critical micelle concentration of the synthesized phosphonium based ILs has been determined by using CE. Also, the electrosmotic flow in the fused silica capillaries are measured with the synthesized ILs and the influence of the alkyl chain length on the same is determined. Such ILs have great potential as novel capillary coatings for CE.