In-syringe dispersive liquid-liquid microextraction

Nano-sized magnetic molecularly imprinted polymer solid-phase microextraction for highly selective recognition and enrichment of sulfamethoxazole from spiked water samples

This research, described ultrasound-assisted dispersive magnetic solid-phase microextraction, which is efficient for the enrichment and determination of sulfamethoxazole, based on magnetic molecularly imprinted polymer (USA-DMSPME-MIP). Meanwhile, the initial characterization of Fe3O4-MIP was completed by conventional methods and well-known protocols to obtain recognition and adsorbing performance at pre-specified optimum conditions. Fe3O4-MIP exhibited information regarding its selective recognition pattern towards sulfamethoxazole. The USA-DMSPME-MIP parameters were optimized by response surface methodology, and based on optimum conditions, this efficient method for the extraction and enrichment of sulfamethoxazole from spiked water samples and quantification by HPLC-UV was used. The enhanced technique indicates the limit of detection is 2 ng mL-1 for sulfamethoxazole, along with excellent linear range with coefficients of determination >0.99 and good recoveries for spiked water samples (94.2 and 98.2 %) with RSDs less than 3.5 %.

Novel reusable and switchable deep eutectic solvent for extraction and determination of curcumin in water and food samples

For the first time, a fast and easy extraction method based on a unique reusable and switchable deep eutectic solvent (made of octylamine, succinic acid, and water as precursors) was presented and utilized for the microextraction and determination of curcumin as a model analyte. The main factors used to induce a phase transition in the as-prepared deep eutectic solvent were solutions of NaOH and HCl. Among the standout characteristics of the suggested deep eutectic solvent are the removal of toxic organic solvents like THF, the lack of a need for centrifugation, and the ability to be reused in subsequent extractions. The influence of effective parameters (i.e., proportions of deep eutectic solvent structure components, volume of prepared deep eutectic solvent, volume and concertation of NaOH, volume of HCl, and salt effect) on the extraction procedure were investigated. The calibration curve also was linear in the range of 35-500 μg L-1 with coefficients of determination (R2) of 0.9976. Limit of detection (S/N = 3) 10.0 μg L-1, the limit of quantification (LOQ) of 35.0 μg L-1, the relative standard deviations (RSDs %) composed of intra-day RSD (4.7) and inter-day RSD (6.4), preconcentration factor of 40.0, enrichment factor of 38.68, and relative recovery of 92.6%-100.3 % were achieved. The reusable and switchable deep eutectic solvent based-dispersive liquid-liquid microextraction technique was proficiently employed to expedite easy and fast extraction of curcumin from water and food samples.

In-syringe low-density solvent dispersive liquid-liquid microextraction of Pd(II) from acidic solutions resulting from hydrometallurgical treatments and quantification by ICP-OES

An in-syringe low-density solvent dispersive liquid-liquid microextraction (IS-LDS-DLLME) is presented for the extraction of palladium from a highly acidic medium before its quantification by inductively coupled plasma optical emission spectroscopy. The extraction solvent was 1-undecanol, and benzil mono-(2-pyridyl) hydrazone was employed as a ligand. Here, no dispersive solvent is needed as the vortex disperses 1-undecanol in the aqueous sample solution. The experimental variables pH, concentration of the ligand, type and quantity of the extraction solvent, vortex time, and addition of NaCl were optimized. The described approach has detection and quantification limits of 0.13 and 0.43 μg L-1, respectively, an enrichment factor of 91, a linear analytical range from 0.4 to 250 μg L-1, and a precision of 1.7-2.0 % (25.0 μg L-1). The approach was used to analyze electronic waste samples and certified reference material.

Recent Progress on Green New Phase Extraction and Preparation of Polyphenols in Edible Oil

With the proposal of replacing toxic solvents with non-toxic solvents in the concept of green chemistry, the development and utilization of new green extraction techniques have become a research hotspot. Phenolic compounds in edible oils have good antioxidant activity, but due to their low content and complex matrix, it is difficult to achieve a high extraction rate in a green and efficient way. This paper reviews the current research status of novel extraction materials in solid-phase extraction, including carbon nanotubes, graphene and metal-organic frameworks, as well as the application of green chemical materials in liquid-phase extraction, including deep eutectic solvents, ionic liquids, supercritical fluids and supramolecular solvents. The aim is to provide a more specific reference for realizing the green and efficient extraction of polyphenolic compounds from edible oils, as well as another possibility for the future research trend of green extraction technology.

Application of instantaneous nebulization dispersive liquid-phase microextraction combined with HPLC for the determination of chalcone and isoflavone in traditional Chinese medicines

A simple and rapid instantaneous nebulization dispersive liquid-phase microextraction method was developed, and combined with high-performance liquid chromatography for determination of the contents of seven analytes in traditional Chinese medicines. In this study, using the sprinkler device to achieve instantaneous synchronous dispersion and extraction, only one spray can rapidly achieve the concentration and enrichment of seven kinds of chalcone and isoflavones. The key factors affecting the extraction efficiency were optimized including the type and volume of extractant, the pH and salt concentration of the sample phase, and the number of dispersion. Under the optimal conditions, the enrichment factor of the target analytes ranged from 103.1 to 180.9, with good linearity and correlation coefficients above 0.9970. The limits of detection ranged from 0.02 to 0.15 ng/mL, with good accuracy (recoveries 91.1 to 108.9%) and precision (relative standard deviations 1.5-7.1%). This method has short extraction time (2 s), low organic solvent consumption and high enrichment effect, so it has a wide application prospects.

Magnetic deep eutectic solvent-based dispersive liquid-liquid microextraction for determination of strobilurin fungicides in water, juice, and vinegar by high-performance liquid chromatography

In this study, a magnetic deep eutectic solvent coupled with dispersive liquid-liquid microextraction using high-performance liquid chromatography (MDES-DLLME-HPLC) was developed to detect strobilurin fungicides. The green hydrophobic MDES synthesized by methyltrioctylammonium chloride, ferric chloride, and heptanoic acid was used as an extraction solvent, which was dispersed by vortex and separated by an external magnetic field. The use of toxic solvents was avoided, and the separation time was reduced. The best experimental results were obtained through single factor and response surface optimization. The method had a good linear relationship with R² > 0.996. The limit of detection (LOD) ranged from 0.001 to 0.002 mg L^-1. The extraction recoveries were 81.9-108.9%. The proposed method was rapid and green, and it has been successfully applied to detection of strobilurin fungicides in water, juice, and vinegar.

A miniaturized liquid-liquid extraction method for further Na, K, Ca, and Mg determination in crude oil by FAAS

In this study, a miniaturized liquid-liquid extraction (LLE) method for pre-concentration of Na, K, Ca, and Mg in crude oil was proposed. Analytes in crude oil were quantitatively extracted to the aqueous phase, followed by flame atomic absorption spectrometry (FAAS) determination. The following parameters were evaluated: type of extraction solution, sample mass, heating temperature and time, stirring time, centrifugation time, and the use of toluene and chemical demulsifier. Accuracy was evaluated by comparing the results obtained by the proposed method (LLE-FAAS) with those obtained after high-pressure microwave-assisted wet digestion and FAAS determination (reference values). No statistical difference was observed between the reference values and those using the optimized conditions for LLE-FAAS: 2.5 g of sample; 1000 μL of 2 mol L^-1 HNO₃, 50 mg L^-1 of chemical demulsifier in 500 μL of toluene, 10 min of heating at 80 °C, 60 s of stirring, and 10 min of centrifugation. Relative standard deviations were lower than 6%. The limits of quantification (LOQ) were 1.2, 1.5, 5.0, and 0.50 μg g^-1 for Na, K, Ca, and Mg, respectively. The proposed miniaturized LLE method presents several advantages, such as ease-of-use, high throughput (up 10 samples can be processed per 1 h), uses a high sample mass reaching low LOQs. In addition, the use of a diluted solution for extraction reduces the amount of reagents (around 40 times) and consequently laboratory residue generation, becoming an environmental friendly method. Suitable LOQs were achieved for analyte determination at low concentration even using a simple and low-cost sample preparation system (miniaturized LLE method) and a relatively low-cost determination technique (FAAS), avoiding the use of microwave ovens and more sensitivity techniques, which are required for routine analyses.

Nanoextraction based on surface nanodroplets for chemical preconcentration and determination

Liquid-liquid extraction based on surface nanodroplets, namely nanoextraction, can continuously extract and enrich target analytes from the flow of a sample solution. This sample preconcentration technique is easy to operate in a continuous flow system with a low consumption of organic solvent and a high enrichment factor. In this review, the evolution from single drop microextraction to advanced nanoextraction will be briefly introduced. Moreover, the formation principle and key features of surface nanodroplets will be summarized. Further, the major findings of nanoextraction combined with in-droplet chemistry toward sensitive and quantitative detection will be discussed. Finally, we will give our perspectives for the future trend of nanoextraction.