Ferrofluid-based liquid-phase microextraction

Deep eutectic solvent-based ferrofluid for vortex-assisted liquid-liquid microextraction of nonsteroidal anti-inflammatory drugs from environmental waters

A novel ferrofluid of Fe3O4 nanoparticles and a deep eutectic solvent (DES) composed of menthol and pentanoic acid was introduced as a green microextraction medium. The ferrofluid was successfully used as an extractant for vortex-assisted liquid-liquid microextraction (VALLME) of nonsteroidal anti-inflammatory drugs (NSAIDs) in environmental waters prior to their determination by HPLC-DAD. Once the ferrofluid was dispersed in the sample by vortex agitation, phase separation could be easily achieved by placing a neodymium magnet next to the tube, which eliminated the centrifugation step and simplified the operational procedure. As a result, the sample pretreatment took only ≈2 min. The experimental parameters, including pH, nanoparticle amount, ferrofluid volume, vortex time, salt amount, and disruptive solvent type and its volume, were optimized stepwise. The method showed linear behavior for all NSAIDs from 5 to 100 μg/L, with limit of detection values and enrichment factors in the ranges of 1.68-2.05 μg/L and 38.9-50.6, respectively. Intra- and Inter-day accuracies obtained from the analysis of spiked river, lake, and tap water samples at low and high-quality control levels (20 and 80 μg/L) ranged from 90.3% to 108.0%, with relative standard deviations less than <12.3%. The results of this study demonstrate that the use of DES-based ferrofluid in VALLME can be considered a simple, environmentally friendly, and reliable alternative for the determination of NSAIDs in environmental waters.

Hydroxyl-rich ferrofluid for efficient liquid phase microextraction of cinnamic acid derivatives in traditional Chinese medicine

In this study, a hydroxyl-rich ferrofluid was prepared by dispersing silica-coated magnetic nanoparticles into a methyltrioctylammonium chloride-glycerol deep eutectic solvent and then employed in the preconcentration of trace-level of cinnamic acid derivatives (caffeic acid, p-hydroxycinnamic acid, ferulic acid, and cinnamic acid) in traditional Chinese medicine prior to high-performance liquid chromatography analysis. The structures of the synthesized materials were characterized by X-ray diffraction and infrared spectroscopy. The experimental parameters affecting the extraction performance, such as deep eutectic solvent composition, dosage of ferrofluid, pH of aqueous sample solution, salt concentration, extraction time, type, and volume of desorption solvent, were studied and optimized. Under the optimum conditions, the enrichment factors of four cinnamic acid derivatives were in the range of 107-114. Low detection limits (0.2-0.9 ng/mL), good precisions (relative standard deviations 1.2%-9.5%), and satisfactory recoveries (96.0%-104.7%) were achieved. Subsequently, the possible microextraction mechanism of the proposed method was explored and elucidated. It showed that the prepared ferrofluid is easily dispersed in the aqueous sample and achieved recovery after the extraction. The developed approach is a simple, convenient, and efficient method for preconcentration and determination of cinnamic acid derivatives in complex matrices.

Effervescent tablet-assisted deep eutectic solvent based on magnetic nanofluid for liquid phase microextraction of tyrosine kinase inhibitors in plasma samples by high-performance liquid chromatography

BACKGROUND

Tyrosine kinase inhibitors (TKIs) are efficient anti-cancer drugs. The analysis of TKIs in the treatment of cancer is important to achieve the highest anti-cancer effects with minimal toxicities. Herein, we report an efficient effervescent tablet-assisted deep eutectic solvent based on nanofluid (ETA-DES-NF) combined with HPLC-UV for the determination of three anti-cancer drugs (erlotinib, imatinib, and nilotinib) in human plasma samples.

METHODS

In this method, a magnetic nanofluid composed of deep eutectic solvent (DES) and Fe3O4@SiO2 nanoparticles was used as an extraction solvent. The deep eutectic solvent acted as a carrier and stabilizer for Fe3O4@SiO2 nanoparticles. A tablet was used in the nanofluid for dispersion. The effervescent tablet was implemented to generate in situ CO2 and provide the effective dispersion of the sorbent into the sample solution for diminishing the extraction time and improving the extraction efficiency. Moreover, the magnetic nanofluid enhanced phase separation efficiency without centrifugation to collect the organic solvent.

RESULTS

The synthesized nanofluid was characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The impact of main parameters, including the type and volume of DES, the composition of the tablet, the composition of the nanofluid and the composition of eluent, were optimized. According to the optimized conditions, the limits of detection (LODs) and the limits of quantitation (LOQs) were from 0.5-0.8 to 1.5-2.4 μg L-1 for imatinib, erlotinib, and nilotinib, respectively. The intra-day and inter-day relative standard deviations (RSD% n = 5) were determined to be 3.1-5% and 6.4-7.5%, respectively.

CONCLUSIONS

The developed method displayed high sensitivity, low consumption of solvent, low cost, simplicity, high recoveries, short extraction time, and good repeatability for determination of three anti-cancer drugs in human plasma samples.

The Use of Ferrofluids in Analytical Sample Preparation: A Review

Ferrofluids (FFs) constitute a type of tunable magnetic material, formed by magnetic nanoparticles suspended in a liquid carrier. The astonishing magnetic properties of these materials and their liquid nature have led to their extended use in different applications, including fields such as magnetochemistry, optics, and biomedicine, among others. Recently, FFs have been incorporated as extractant materials in magnetic-driven analytical sample preparation procedures, thus, permitting the development of different applications. FF-based extraction takes advantage of both the magnetic susceptibility of the nanoparticles and the properties of the liquid carrier, which are responsible for a wide variety of interactions with analytes and ultimately are a key factor in achieving better extraction performance. This review article classifies existing FFs in terms of the solvent used as a carrier (organic solvents, water, ionic liquids, deep eutectic solvents, and supramolecular solvents) while overviewing the most relevant analytical applications in the last decade.

Rapid ionic liquid-based ultrasound assisted dual magnetic microextraction to preconcentrate and separate cadmium-4-(2-thiazolylazo)-resorcinol complex from environmental and biological samples

A rapid and innovative microextraction technique named as, ionic liquid-based ultrasound-assisted dual magnetic microextraction (IL-UA-DMME) was developed for the preconcentration and extraction of trace cadmium from environmental and biological samples, prior to analyzed by flame atomic absorption spectrometry (FAAS). The proposed method has many obvious advantages, including evading the use of organic solvents and achieved high extraction yields by the combination of dispersive liquid-liquid microextraction (DLLME) and magnetic mediated-solid phase extraction (MM-SPE). In this approach ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] play an important role to extract the cadmium-4-(2-thiazolylazo)-resorcinol (Cd-TAR) complex from acid digested sample solutions and ultrasonic irradiation was applied to assist emulsification. After then, dispersed small amount of Fe3O4 magnetic nanoparticles (MNPs) in sample solutions to salvaged the IL and complete phase separation was attained. Some analytical parameters that influencing the efficiency of proposed (IL-UA-DMME) method, such as pH, volume of IL, ligand concentration, ultra-sonication time, amount of Fe3O4 MNPs, sample volume and matrix effect were optimized. Limit of detection (LOD) and enrichment factor (EF) of the method under optimal experimental conditions were found to be 0.40μgL(-1) and 100, respectively. The relative standard deviation (RSD) of 50μgL(-1) Cd was 4.29%. The validity and accuracy of proposed method, was assessed to analyzed certified reference materials of fortified lake water TMDA-54.4, SPS-WW2 waste water, spinach leaves 1570a and also checked by standard addition method. The obtained values showed good agreement with the certified values and sufficiently high recovery were found in the range of 98.1-101% for Cd. The proposed method was facile, rapid and successfully applied for the determination of Cd in environmental and different biological samples.

Evaluation of Superparamagnetic Silica Nanoparticles for Extraction of Triazines in Magnetic in-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography

The use of magnetic nanomaterials for analytical applications has increased in the recent years. In particular, magnetic nanomaterials have shown great potential as adsorbent phase in several extraction procedures due to the significant advantages over the conventional methods. In the present work, the influence of magnetic forces over the extraction efficiency of triazines using superparamagnetic silica nanoparticles (NPs) in magnetic in tube solid phase microextraction (Magnetic-IT-SPME) coupled to CapLC has been evaluated. Atrazine, terbutylazine and simazine has been selected as target analytes. The superparamagnetic silica nanomaterial (SiO₂-Fe₃O₄) deposited onto the surface of a capillary column gave rise to a magnetic extraction phase for IT-SPME that provided a enhancemment of the extraction efficiency for triazines. This improvement is based on two phenomena, the superparamegnetic behavior of Fe₃O₄ NPs and the diamagnetic repulsions that take place in a microfluidic device such a capillary column. A systematic study of analytes adsorption and desorption was conducted as function of the magnetic field and the relationship with triazines magnetic susceptibility. The positive influence of magnetism on the extraction procedure was demonstrated. The analytical characteristics of the optimized procedure were established and the method was applied to the determination of the target analytes in water samples with satisfactory results. When coupling Magnetic-IT-SPME with CapLC, improved adsorption efficiencies (60%–63%) were achieved compared with conventional adsorption materials (0.8%–3%).