Vortex-assisted ionic liquid microextraction coupled to flame atomic absorption spectrometry for determination of trace levels of cadmium in real samples

Abstract

A simple and rapid vortex assisted ionic liquid based liquid–liquid microextraction technique (VALLME) was proposed for preconcentration of trace levels of cadmium. According to this method, the extraction solvent was dispersed into the aqueous samples by the assistance of vortex agitator. Cadmium preconcentration was mediated by chelation with the 8-hydroxyquinoline (oxine) reagent and an IL, 1-octyl-3-methylimidazolium hexafluorophosphate ([Omim][PF6]) was chosen as the extraction solvent to extract the hydrophobic complex. Several variables such as sample pH, concentration of oxine, volume of [Omim][PF6] and extraction time were investigated in details and optimum conditions were selected. Under the optimum conditions, the limit of detection (LOD) was 2.9 μg L−1 for Cd (ІІ) and relative standard deviation (RSD%) for five replicate determinations of 125 μg L−1 was 4.1%. The method was successfully applied to the determination of cadmium in tap water, apple and rice samples.

Distribution Equilibria of Amphoteric 8-Quinolinol between 1-Alkyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide and Aqueous Phases and Their Effect on Ionic Liquid Chelate Extraction Behavior of Iron(III)

“…26 8-Hydroxyquinoline (HQ) is a well-known bidentate extraction reagent. Although there are many papers on use of HQ in IL chelate extraction, [27][28][29][30][31][32][33][34][35][36][37] the distribution behavior of HQ between IL and aqueous phases has not been investigated. HQ is an amphoteric compound, which has the following two acid-base equilibria:…”

Layer-by-layer encapsulated nano-emulsion of ionic liquid loaded with functional material for extraction of Cd2+ ions from aqueous solutions

“…With the extraction efficiency of the optimized system as high as of previously reported emulsion-based extraction systems [13][14][15], the use of the layer by layer ionic liquid-core capsules is preferable to using emulsions since they are more stable [47,54] and easier to remove from aqueous solutions than non-encapsulated emulsion droplets, while being suitable for performing the extraction in cases when in-situ emulsification is not possible. Future work, therefore, will focus on finding a way to safely concentrate multi-layered capsules in order to add more polyelectrolyte layers onto them to further increase their mechanical strength thus making filtration a viable option for post-extraction capsule removal, as well as to make them suitable for efficient extraction of Cd 2+ from more concentrated solutions.…”

“…Moreover, nano-emulsions are kinetically stable, and their small size makes them resistant to sedimentation or creaming [12], providing greater control over the extraction process, and allowing for greater storage times. Several different methods for emulsification of ionic liquids have been reported including dispersing under high temperature [13], ultrasound [14] and vortex-assisted emulsification [15], all of which are used as a part of dispersive liquid-liquid micro-extraction procedure where emulsions are created within a working sample containing extractable ions [16][17][18][19]. Other techniques that can also be used to create emulsions of ionic liquids are high-energy methods such as high-pressure homogenization [20], and low-energy methods such as spontaneous emulsification [21] and the phase inversion temperature method [22].…”

Determination of Traces of Ni, Cu, and Zn in Wastewater and Alloy Samples by Flame-AAS after Ionic Liquid-Based Dispersive Liquid Phase Microextraction

“…Extraction and determination of the studied metal ions in wastewater and alloy samples by the proposed method was compared with other methods [36][37][38][39][40][41][42][43][44][45] and the results are shown in Table 4. It can be seen from Table 4 that extraction time in the in situ IL-DLLME procedure is very short and only 7 min are needed before instrumental analysis.…”