Fabrication and characterization of magnetic molecularly imprinted polymer based on deep eutectic solvent for specific recognition and quantification of vanillin in infant complementary food.

A magnetic molecularly imprinted polymer based on deep eutectic solvent was synthesized for specific identification and quantification of vanillin. Fe3O4@SiO2-CC and deep eutectic solvent were applied as the carrier of magnetic material and functional monomer, respectively. According to composition and morphology characterizations and adsorption kinetics, the imprinted polymer had excellent advantages on adsorption capacity and identification specificity for vanillin compared with non-imprinted polymer, while its reusability still remained stable. According to the high-performance liquid chromatography, the detection method based on imprinted polymer produced satisfactory analytical results. The limit of quantification was 0.2 µg·mL-1. The mean spiked recoveries for vanillin ranged from 91.2% to 100.2% with intra- and inter-day precision were both less than 7.2%. Compared to traditional extraction methods, this method presented best adsorption and extraction performances. In summary, the method could be further applied to the specific separation and quantification of vanillin in infant complementary food.

[Progress in the application of deep eutectic solvents to extraction and separation technology].

With the rapid development of green chemistry, the design and application of the related methods and requisite solvents have received increasing attention in recent years. Deep eutectic solvents (DESs) are mixtures formed from a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD). Generally, ionic liquids (ILs) and DESs have similar physical and chemical properties, and hence, find application in the same fields. However, DESs have many advantages over ILs, such as non-toxicity, environmental friendliness, low cost, and biodegradability. Thus, there are many areas where DESs play a key role and act as new, efficient green extraction solvents. DESs can aid the extraction and separation of different target compounds from a variety of samples, thus promoting the rapid development of sample pretreatment technology. As extraction solvents, DESs offer unique advantages. In dispersive liquid-liquid microextraction (DLLME), DESs show incredible ability to extract residual drugs, metal ions, and bioactive components from complex matrices, which would require complicated sample preparation steps when using traditional organic extraction solvents. Compared with traditional organic extraction solvents, DESs have considerable merits of greenness, hypotoxicity, higher extraction efficiency, etc. Moreover, as a dispersant, a DES can accelerate the diffusion of the extractant in the sample solution during DLLME, owing to its benefits of miniaturization and low cost. Traditional dispersants such as methanol and acetonitrile have many disadvantages, including high volatility, flammability, and toxicity, while DESs are environmentally friendly. Therefore, the combination of DES and DLLME has recently gained prominence in the field of sample preparation. Additionally, the combination of DES and solid-phase extraction (SPE) has broad application prospects. By virtue of their diverse functions, DESs have been used as eluents, in combination with a solid-phase extraction column and a stir bar, to elute analytes from the sorbent surface. The molar ratio of the HBA and HBD is one of the important factors influencing the elution efficiency. DESs can be combined with magnetic multiwalled carbon nanotubes, magnetic graphene oxide, and other nanocomposites to specifically adsorb target analytes through hydrogen bonding, π-π forces, and electrostatic forces. In addition, the DES can be used in the synthesis of magnetic nanocomposites and molecularly imprinted polymers when combined with magnetic materials. Magnetic nanocomposites functionalized with DES show excellent performance and high efficiency in the extraction process. The combination of DES and magnetic materials would promote the development of magnetic materials for green chemistry and expand the application of DES to several other fields. However, to the best of our knowledge, research on the microstructure, physical and chemical properties, and extraction mechanism of DESs is still in its nascent stage. Therefore, exploring the theoretical mechanism and applications of new DESs with special functions would be an essential future research direction. This article integrates the research progress of DESs in extraction separation technology; introduces the preparation, properties, and classification of DESs; and summarizes the applications of DESs in DLLME and SPE.

Fe3O4/graphene molecularly imprinted composite for selective separation of catecholamine neurotransmitters and their analysis in rat brain tissues.

In this study, a novel of magnetic molecularly imprinted polymers (Fe3O4/GO/DMIPs) with multi-targets recognizing function were prepared by surface molecular imprinting technique adopting isoprenaline as the dummy-template molecule and graphene oxide (GO) as the carrier. The morphology, structures and magnetic properties of nanosorbents were characterized and assessed in detail and the results indicated that the 3D recognition cavities and matching functional groups with catecholamine neurotransmitters (CNs) were successfully fabricated on Fe3O4/GO surface. Moreover, the kinetic, isothermal and selective adsorption experiments were conducted to further reveal the adsorption behavior of adsorbent toward CNs and the results showed that the Fe3O4/GO/DMIPs possessed high adsorption capacity, rapid binding rate and excellent selectivity for CNs. On this basis, the Fe3O4/GO/DMIPs were further applied as adsorbent of magnetic solid-phase extraction (MSPE) for selective recognition and separation of CNs (dopamine, epinephrine, norepinephrine) followed by UPLC-MS/MS detection. The crucial parameters affecting the extraction efficiency were systematically optimized by Box-Behnken statistical design. Under the optimum conditions, satisfactory linearity (r > 0.99) was obtained with the lower limit of quantification from 0.53 to 1.93 ng mL-1. The accuracy (RE) ranged from -7.6% to 6.4% and the intra- and inter-day precisions were not more than 8.7% and 10.2%, respectively. Hence, the strategy proposed in this study might be used for high selectivity recognition and determination of CNs in complex biological matrices, which would provide a basis and reference for its application in the fields of separation and clinical monitoring.

Extraction optimization of accelerated solvent extraction for eight active compounds from Yaobitong capsule using response surface methodology: Comparison with ultrasonic and reflux extraction.

This work described the development of a novel method for simultaneous extraction of eight active compounds (including catechin, albiflorin, paeoniflorin, ferulic acid, ginsenoside Rg1, tetrahydropalmatine, ginsenoside Rb1 and osthole) from Yaobitong capsule by accelerated solvent extraction (ASE). Response surface methodology (RSM) with desirability functions was employed to optimize the extraction conditions yielding the optimal conditions of ASE (extraction time 8 min, extraction temperature 80 °C, extraction solvent 70% methanol and flushing volume 100%). A high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD) method was developed and validated for simultaneous quantification of the eight compounds in Yaobitong capsule. The values of correlation coefficient (R) were satisfactory between 0.9992 and 0.9999 over the linear concentration range of 0.5-1000 µg mL-1. It was found that the limits of detection (LODs) and the limits of quantification (LOQs) for the eight active compounds were 0.10-2.90 µg•mL-1 and 0.30-9.40 µg•mL-1, respectively. The recoveries of the eight main active compounds in Yaobitong capsule were in the range of 93.31%-106.22%. And the contents of the analytes extracted by ASE under the optimal conditions were compared to traditional solvent extraction methods, such as ultrasonic and reflux extraction. The results indicated that the ASE method proved to be more suitable for the extract of active compounds in Yaobitong capsule, which could obtain higher extraction efficiency. At last, the proposed method was applied to analyze ten batches of actual samples, which provided high extraction efficiency and had wide potential application in the analysis of traditional Chinese medicines.

Eco-friendly ultrasonic assisted liquid-liquid microextraction method based on hydrophobic deep eutectic solvent for the determination of sulfonamides in fruit juices.

A sensitive, fast, eco-friendly ultrasound assisted liquid-liquid microextraction (LLME) in combination with hydrophobic deep eutectic solvent (DES) method was developed to preconcentrate and extract sulfonamides in fruit juices, prior to high-performance liquid chromatographic (HPLC) analysis. The DES was synthesized with trioctylmethylammonium chloride (TAC) and 2-octanol at the molar ratio of 1:2. Some parameters which affected the extraction efficiency were investigated and optimized, including the volume of DES, extraction method, extraction time, pH. Under the optimum conditions, good linearity (r = 0.9999) in the range of 0.1-50 µg mL-1 was obtained. The limit of detection (LOD) was 0.02-0.05 µg mL-1. And the accuracy of the developed method was confirmed by analysis of spike method, the recoveries were in the range of 88.09-97.84% at the spike levels of 2-20 µg mL-1 in fruit juices.

[A high-performance liquid chromatography-tandem mass spectrometry method for the quantitative determination of four genotoxic impurities in gefitinib].

In this work, a method for the determination of the amounts of the four genotoxic impurities in gefitinib has been developed. A simple and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) approach has been developed, optimized, and validated. The genotoxic impurities were 3-chloro-4-fluoroaniline, 3,4-difluoroaniline, 3-fluoro-4-chloroaniline, and 3,4-dichloroaniline. Separation was achieved on an Inertsil ODS-3 column (100 mm×3.0 mm, 3 µm). The column temperature was 40 ℃, and the running time was 12 min. A triple quadrupole mass detector with positive electrospray ionization in the multiple reaction monitoring (MRM) mode was applied. The method was validated in terms of its specifi-city, linearity, precision, accuracy, stability, and robustness. The correlation coefficient of each impurity was higher than 0.999 in the range of 0.6-96.0 µg/L. The limits of detection (LODs) and limits of quantity (LOQs) were in the ranges of 0.2-2.0 µg/L and 0.6-6.0 µg/L, respectively. The recoveries of all impurities at 6, 30, and 60 µg/L were within 91.0%-98.5%. All impurities were stable within 2 h. After detection, only 3-chloro-4-fluoroaniline was detected in the batch number 16052301 and R16052501-1 gefitinib samples, but its concentration was below the impurity limit (6 mg/L). This method is simple, reliable, and suitable for the determination of four genotoxic impurities in gefitinib. It can be further applied as a reference for quality control.