Double salts of ionic-liquid-based surfactants in microextraction: application of their mixed hemimicelles as novel sorbents in magnetic-assisted micro-dispersive solid-phase extraction for the determination of phenols

Abstract

The use of mixed hemimicelles of ionic liquid (IL)-based surfactants in a magnetic-based micro-dispersive solid-phase extraction (m-μdSPE) approach is described. Not only is the symmetric monocationic IL-based surfactant 1,3-didodecylimidazolium bromide (C12C12Im-Br) studied for first time in m-μdSPE, but double-salt (DS) IL (DSIL)-based surfactants are also examined. Nine DSIL-based surfactants were formed by combination of C12C12Im-Br with other IL-based surfactants, including nonsymmetric monocationic and dicationic ILs combined at three different molar fractions. The analytical application was focused on the determination of a group of eight phenols, including bisphenol A, in water samples. The best results were obtained with the DSIL formed by C12C12Im-Br (molar fraction 0.5) and 1-hexadecyl-3-methylimidazolium bromide (C16MIm-Br), after proper optimization of the overall method in combination with high-performance liquid chromatography (HPLC) and diode-array detection (DAD). The optimum conditions for 100 mL of water samples require a small amount (10 mg) of Fe3O4 magnetic nanoparticles, a low content (5.0 mg of C12C12Im-Br and 3.9 mg of C16MIm-Br) of the selected DSIL, pH 11, a sonication time of 2.5 min, and an equilibration time of 5 min with the aid of NdFeB magnets, followed by elution of phenols, evaporation, and reconstitution with 0.5 mL of acetonitrile. The overall m-μdSPE-HPLC-DAD method is characterized for limits of detection down to 1.3 μg · L(-1), intraday relative standard deviations lower than 13 % (n = 3), and interday relative standard deviations lower than 17 % (n = 9), with a spiking level of 15 μg · L(-1); with enrichment factors between 15.7 and 141, and average relative recoveries of 99.9 %.

Platform construction and extraction mechanism study of magnetic mixed hemimicelles solid-phase extraction

“…However, in most cases, this method needs only 6.0 mg Fe 3 O 4 NPs and 0.3 mg C 16 mimBr for 4 mL of sample solution and the total cost were less than 0.1 dollar. Therefore, compared with the conventional methods, less requirement on support material and surfactant is a significant advantage of magnetic mixed hemimicelles solid-phase extraction technique313233.…”

Magnetic ionic liquids as non-conventional extraction solvents for the determination of polycyclic aromatic hydrocarbons

“…ILs [45,46] orIL-based surfactants [25,27].The use of high ionic strength can be accomplished only when Fe 3 O 4 coated with silica (Fe 3 O 4 @SiO 2 ) is used, but requires an additional step in the preparation of the material [24,47]. which the addition of salts has a negative effect in the extraction efficiency [25,27,45,46]). The MIL-based microextraction method is therefore clearly valid for aqueous samples with a high salt content.…”

“…Thus, the overall method is quite simple because it does not require centrifugation or filtrationto separate the magnetic material from the sample once extraction has been accomplished. ILs [23,24] and IL-based surfactants [25][26][27] have been described as extractants presenting a magnetic core (normally magnetite:…”

Long‐chain ionic liquid based mixed hemimicelles and magnetic dispersed solid‐phase extraction for the extraction of fluorescent whitening agents in paper materials

“…For example, 1‐dodecyl‐3‐methylimidazolium tetrafluoroborate was used as an additive of CE . Some researchers have proved that the excellent properties of LCILs make it possible to be a suitable modified material in MH‐SPE . The results show that LCILs have superior effect than CTAB.…”