Flow-injection sample preconcentration for ion-pair chromatography of trace metals in waters

Ion‐Pair Formation in the Ionic Liquid 1‐Ethyl‐3‐methylimidazolium Bis(triflyl)imide as a Function of Temperature and Concentration

“…Since ILs are entirely composed of ions, the formation of ion pairs is expected to be one essential feature for describing both solvation in ILs and solvation of ILs in other media. The phenomenon of ion‐pair formation is by itself of fundamental importance to the chemical field, as it influences reaction rates or may be exploited in numerous chemical applications such as ion‐pair chromatography7 or ion‐selective electrodes 8. An indication of ion‐pair formation in imidazolium‐based ILs was previously reported,10–12 and a series of recent experimental and theoretical investigations show evidence for strong hydrogen‐bonding‐type interactions involving the acidic C(2)H proton of the imidazolium cation 13–21.…”

Flow Analysis as Advanced Branch of Flow Chemistry

“…The most commonly performed on-line operations include preconcentration or separation of analyte from the matrix in flow-through reactors with solid sorbents, in open-tubular reactors or in membrane modules [24]. This is widely employed in hyphenation of FIA systems with atomic spectroscopy instruments [26], gas [27] and liquid [28] chromatography, or capillary electrophoresis [29]. Large attention is focused on development of FIA systems with flow-through reactors with immobilized enzymes, antibodies, and various nanoparticles [30], but also with flow-through packed-reactors allowing the carrying on other heterogeneous reactions on-line without pumping continuously solutions.…”

Advanced analytical methods and sample preparation for ion chromatography techniques

“…The general procedure is passing the sample solution through the solid phase cartridge that is lled with the sorbent material suitable for the separation, which either retains the analyte ions or retains the interfering matrix components. [62][63][64][65] By preconcentration of the ions to be determined in a pre-chromatographic step, it is possible to achieve considerable improvements in the sensitivity and better matrix elimination. If matrix components are retained on the solid phase, the determination is carried out on the solution leaving the column.…”

“…Large volume injection can improve the sensitivity by up to one to two orders of magnitude, but only for samples with low ionic strength. [62][63][64][65] By preconcentration of the ions to be determined in a pre-chromatographic step, it is possible to achieve considerable improvements in the sensitivity and better matrix elimination. 65 Whereas in individual cases, it is more important to selective preconcentration of individual ion in the presence of great amount of other ions and selective multi-component preconcentration from complex matrix.…”