Solvent-tuned perovskite heterostructures enable visual linoleic acid assay and edible oil species discrimination via wavelength shift.

Linoleic acid (LA) detection and edible oils discrimination are essential for food safety. Recently, CsPbBr3@SiO2 heterostructures have been widely applied in edible oil assays, while deep insights into solvent effects on their structure and performance are often overlooked. Based on the suitable polarity and viscosity of cyclohexane, we prepared CsPbBr3@SiO2 Janus nanoparticles (JNPs) with high stability in edible oil and fast halogen-exchange (FHE) efficiency with oleylammonium iodide (OLAI). LA is selectively oxidized by lipoxidase to yield hydroxylated derivative (oxLA) capable of reacting with OLAI, thereby bridging LA content to naked-eye fluorescence color changes through the anti-FHE reaction. The established method for LA in edible oils exhibited consistent results with GC-MS analysis (p > 0.05). Since the LA content difference between edible oils, we further utilized chemometrics to accurately distinguish (100%) the species of edible oils. Overall, such elaborated CsPbBr3@SiO2 JNPs enable a refreshing strategy for edible oil discrimination.

Hierarchical Self-Assembly Molecular Building Blocks as Intelligent Nanoplatforms for Ovarian Cancer Theranostics.

Hierarchical self-assembly from simple building blocks to complex polymers is a feasible approach to constructing multi-functional smart materials. However, the polymerization process of polymers often involves challenges such as the design of building blocks and the drive of external energy. Here, a hierarchical self-assembly with self-driven and energy conversion capabilities based on p-aminophenol and diethylenetriamine building blocks is reported. Through ß-galactosidase (ß-Gal) specific activation to the self-assembly, the intelligent assemblies (oligomer and superpolymer) with excellent photothermal and fluorescent properties are dynamically formed in situ, and thus the sensitive multi-mode detection of ß-Gal activity is realized. Based on the overexpression of ß-Gal in ovarian cancer cells, the self-assembly superpolymer is specifically generated in SKOV-3 cells to achieve fluorescence imaging. The photothermal therapeutic ability of the self-assembly oligomer (synthesized in vitro) is evaluated by a subcutaneous ovarian cancer model, showing satisfactory anti-tumor effects. This work expands the construction of intelligent assemblies through the self-driven cascade assembly of small molecules and provides new methods for the diagnosis and treatment of ovarian cancer.

Trinity Strategy: Enabling Perovskite as Hydrophilic and Efficient Fluorescent Nanozyme for Constructing Biomarker Reporting Platform.

Water instability and sensing homogeneity are the Achilles' heel of CsPbX3 NPs in biological fluids application. This work reports the preparation of Mn2+:CsPbCl3@SiO2 yolk-shell nanoparticles (YSNPs) in aqueous solutions created through the integration of ligand, surface, and crystal engineering strategies. The SN2 reaction between 4-chlorobutyric acid (CBA) and oleylamine (OAm) yields a zwitterionic ligand that facilitates the dispersion of YSNPs in water, while the robust SiO2 shell enhances their overall stability. Besides, Mn2+ doping in YSNPs not only introduces a second emission center but also enables potential postsynthetic designability, leading to the switching from YSNPs to MnO2@YSNPs with excellent oxidase (OXD)-like activity. Theoretical calculations reveal that electron transfer from CsPbCl3 to in situ MnO2 and the adsorption-desorption process of 3,3',5,5'-tetramethylbenzidine (TMB) synergistically amplify the OXD-like activity. In the presence of ascorbic acid (AA), Mn4+ in MnO2@YSNPs (fluorescent nanozyme) is reduced to Mn2+ and dissociated, thereby inhibiting the OXD-like activity and triggering fluorescence "turn-on/off", i.e., dual-mode recognition. Finally, a biomarker reporting platform based on MnO2@YSNPs fluorescent nanozyme is constructed with AA as the reporter molecule, and the accurate detection of human serum alkaline phosphatase (ALP) is realized, demonstrating the vast potential of perovskites in biosensing.

Nanoporous Crystalline Materials for the Recognition and Applications of Nucleic Acids.

Nucleic acid plays a crucial role in countless biological processes. Hence, there is great interest in its detection and analysis in various fields from chemistry, biology, to medicine. Nanoporous crystalline materials exhibit enormous potential as an effective platform for nucleic acid recognition and application. These materials have highly ordered and uniform pore structures, as well as adjustable surface chemistry and pore size, making them good carriers for nucleic acid extraction, detection, and delivery. In this review, the latest developments in nanoporous crystalline materials, including metal organic frameworks (MOFs), covalent organic frameworks (COFs), and supramolecular organic frameworks (SOFs) for nucleic acid recognition and applications are discussed. Different strategies for functionalizing these materials are explored to specifically identify nucleic acid targets. Their applications in selective separation and detection of nucleic acids are highlighted. They can also be used as DNA/RNA sensors, gene delivery agents, host DNAzymes, and in DNA-based computing. Other applications include catalysis, data storage, and biomimetics. The development of novel nanoporous crystalline materials with enhanced biocompatibility has opened up new avenues in the fields of nucleic acid analysis and therapy, paving the way for the development of sensitive, selective, and cost-effective diagnostic and therapeutic tools with widespread applications.

Macrophage-Inspired Degradation-Activation System Enables Ultrasensitive Multicolor Detection of Haloacetic Acids via Janus Perovskite Halide Exchange.

Haloacetic acids (HAAs), as representative disinfection byproducts, have the potential hazards of teratogenesis, carcinogenesis, and mutagenesis. Herein, inspired by the scavenging physiology of macrophages and taking advantage of the unique properties of perovskites, we design a biomimetic integrated three-step workflow, named the macrophage-inspired degradation-activation system (MIDAS), for the detection of HAAs in aqueous samples. First, HAAs are "devoured" by methyl t-butyl ether (MTBE) from a sample. Then, ultraviolet C is utilized to induce the photolysis of MTBE and the dehalogenation of HAAs. Third, the photoinduced product, tertiary butyl haloalkane, can activate the vacancy defect-facilitated halide exchange of perovskites, generating multicolor fluorescent signals. The MIDAS realizes the rapid (<5 min), ultrasensitive (limit of detection: 30 and 15 ppb), and accurate (recovery: 95.2-109.4%) quantification of dichloroacetic acid and dibromoacetic acid in real water samples. Furthermore, a chemometrics-supported MIDAS portable platform is established for the visual semi-quantification of HAAs and the discrimination of binary mixed HAAs on site. The MIDAS-based strategy provides a highly efficient approach to trigger the perovskite halide exchange and shows the Midas touch-like ability in the fluorescent assay of HAAs in aqueous samples. To our knowledge, this is the first universal multicolor fluorimetry and the first application of perovskites for HAA detection.

In Situ Formation of o-Phenylenediamine Cascade Polymers Mediated by Metal-Organic Framework Nanozymes for Fluorescent and Photothermal Dual-Mode Assay of Acetylcholinesterase Activity.

A fluorescent and photothermal dual-mode assay method was established for the detection of acetylcholinesterase (AChE) activity based on in situ formation of o-phenylenediamine (oPD) cascade polymers. First, copper metal-organic frameworks of benzenetricarboxylic acid (Cu-BTC) were screened out as nanozymes with excellent oxidase-like activity and confinement catalysis effect. Then, an ingenious oPD cascade polymerization strategy was proposed. That is, oPD was oxidized by Cu-BTC to oPD oligomers with strong yellow fluorescence, and oPD oligomers were further catalyzed to generate J-aggregation, which promotes the formation of oPD polymer nanoparticles with a high photothermal effect. By utilizing thiocholine (enzymolysis product of acetylthiocholine) to inhibit the Cu-BTC catalytic effect, AChE activity was detected through the fluorescence-photothermal dual-signal change of oPD oligomers and polymer nanoparticles. Both assay modes have low detection limitation (0.03 U L-1 for fluorescence and 0.05 U L-1 for photothermal) and can accurately detect the AChE activity of human serum (recovery 85.0-111.3%). The detection results of real serum samples by fluorescent and photothermal dual modes are consistent with each other (relative error ≤ 5.2%). It is worth emphasizing that this is the first time to report the high photothermal effect of oPD polymers and the fluorescence-photothermal dual-mode assay of enzyme activity.

A selective dual-response biosensor for tyrosinase monophenolase activity based on lanthanide metal-organic frameworks assisted boric acid-levodopa polymer dots.

Tyrosinase (TYR) monophenolase activity plays a key role in the development of diseases such as melanoma. The selective and sensitive detection of TYR monophenolase activity is a persistent challenge. Here, by integrating fluorescent polymer dots and a luminescent lanthanide metal-organic framework (Ln-MOF), we proposed an on-off dual-response biosensor for the sensitive and selective detection of TYR monophenolase. The Ln-MOF was prepared with Eu3+ and monoaromatic ligand dipicolinic acid (DPA), and it plays multiple functions such as fluorescent internal standard, chromaticity shift enhancement and fluorescence sensing. In alkaline boric acid (BA) buffer, L-tyrosine is converted into BA-levodopa by TYR monophenolase. Then, with the assistance of Eu-DPA, BA-levodopa is initiated by diethylaminepropyltrimethoxysilane (DAMO) to generate BA-levodopa polymer dots, which turn on strong blue fluorescence (crosslink-enhanced emission) and meanwhile quench the red fluorescence of Eu-DPA through enhanced photo-induced electron transfer. Thus, the sensitive and selective dual-response sensing to TYR monophenolase is achieved. Both DAMO and BA play significant roles in the synthesis of strong fluorescence polymer dots, and another key role of BA is to inhibit TYR diphenolase activity. Furthermore, chromaticity shift value-based quantification greatly improves the response linearity. The linear range is 0.05-2 U mL-1 (r = 0.9966), and the limit of detection is 0.004 U mL-1. The precise and accurate quantification of TYR monophenolase activity in saliva samples is realized (recovery of 96.9-102.0%, relative standard deviation < 9.56%). To our knowledge, it is the first highly-sensitive double-response biosensor for TYR monophenolase activity.

Long-chain alkanol-alkyl carboxylic acid-based low-viscosity hydrophobic deep eutectic solvents for one-pot extraction of anthraquinones from Rhei Radix et Rhizoma.

Natural long-chain alkanol and alkyl carboxylic acid were used to prepare novel hydrophobic deep eutectic solvents (HDESs). These HDESs are liquid at room temperature and have low viscosity (<12.26 mPa‧s), low polarity (lower than that of methanol, ChCl-based deep eutectic solvents and other reported HDESs), and low density (<0.928 g/mL). A simple one-pot method based on a novel HDES-water two-phase extraction system was constructed for the extraction of weak-polarity bioactive components, anthraquinones, from Rhei Radix et Rhizoma. This HDES-based new extraction method does not consume hazardous organic solvents and can obtain a total anthraquinone yield of 21.52 mg/g, which is close to that obtained by the Chinese pharmacopoeia method (21.22 mg/g) and considerably higher than those by other reported HDESs-based extraction methods (14.20-20.09 mg/g, p < 0.01). The high extraction yield can be mainly attributed to the severe destruction of the RRR cell walls by the extraction system and the excellent dissolving ability of novel HDESs for anthraquinones.

Portable visual assay of Bacillus anthracis biomarker based on ligand-functionalized dual-emission lanthanide metal-organic frameworks and smartphone-integrated mini-device.

A single-functionalized ligand single-Ln3+ based dual-emission Ln-MOF fluorescent sensor was established for portable and visual dipicolinic acid (DPA, Bacillus anthracis biomarker) detection. First, a theory calculation-based prediction model was developed for designing single-functionalized ligand single-Ln3+ dual-emission Ln-MOFs. The model consisted of three calculation modules: intramolecular hydrogen bonds, excited state energy levels, and coordination stability with Ln3+ of ligands. Tb3+ and Eu3+ were selected as metal luminescence centers, PTA-X (PTA: p-phthalic acid, X = NH2, CH3, H, OH) with different functional groups as one-step functionalization ligands, and the luminescent feature of four Tb-MOFs and four Eu-MOFs was predicted with the model. Coupled with prediction results and experimental verification results, Tb-PTA-OH was rapidly determined to be the sole dual-emission Ln-MOF. Then, Tb-PTA-OH was applied to DPA detection by ratiometric fluorescence, and an ultra-low limit of detection (13.4 nM) was obtained, which is much lower than the lowest anthrax infectious dose (60 µM). A portable visual assay method based on paper-microchip and smartphone integrated mini-device was further established (limit of qualification 0.48 µM). A new sensing mechanism and a "triple gates" selectivity mechanism to DPA were proposed. This work reveals guidelines for material design and mini-device customization in detecting hazardous substances.

Hydrophobic magnetic nanoparticle assisted catanionic surfactant supramolecular solvent microextraction of multiresidue antibiotics in water samples.

A novel extraction technique i.e. hydrophobic magnetic nanoparticle (MNP)-assisted in situ supramolecular solvent (SUPRAS) microextraction was proposed, and it was applied for the analysis of sulfonamides (SAs) and fluoroquinolones (FQs) in aqueous samples, coupled with high performance liquid chromatography-UV detection (HPLC-UV). In this extraction method, hexafluoroisopropanol-mediated salt-free catanionic surfactant based SUPRAS in situ microextraction was initially carried out; then, the SUPRAS was quickly adsorbed by the hydrophobic magnetic nanoparticles and gathered by an external magnetic field. This can greatly shorten the separation time and overcome the dependence on centrifugation, and also perform a secondary extraction of free analytes (not extracted by SUPRAS) from water samples. The magnetic separation ability of different hydrophobic MNPs was evaluated by adsorbing supramolecular aggregates from the water sample. The effective parameters affecting the extraction efficiency of the analytes were investigated and optimized using the one variable at a time method. About 3 min was required to realize the extraction of analytes with an enrichment factor (EF) of 12-53 for SAs and 79-118 for FQs. Compared with the centrifugation-assisted SUPRAS microextraction, the hydrophobic MNP-assisted SUPRAS microextraction obtained much better extraction and preconcentration efficiency. The proposed novel extraction method with HPLC-UV provided LODs of 0.21-0.76 ng mL-1 for SAs and 0.10-0.18 ng mL-1 for FQs. Good linearity was obtained with correlation coefficients ranging from 0.9962 to 0.9999. The intra- and inter-day recoveries of the target antibiotics were in the range of 92.0-111.3% with RSD% below 10.4%. The method was successfully applied to determine SAs and FQs in real water samples, such as lake water, river water, reservoir water, and wastewater.

Multifunctional nanoscale lanthanide metal-organic framework based ratiometric fluorescence paper microchip for visual dopamine assay.

Dopamine (DA) plays a significant role in the human body and cerebral nervous system, and the accurate and rapid assay of DA is essential for the diagnosis of related diseases. Herein, we proposed a turn-on ratiometric fluorescent DA assay strategy by integrating a specific DA-resorcinol chemical reaction with a multifunctional lanthanide metal-organic framework (Ln-MOF). First, Eu-BTC (1,3,5-benzenetricarboxylic acid) was synthesized and further modified to obtain Cu@Eu-BTC, which simultaneously plays multiple roles such as fluorescence internal standard, nanoreactor, cooperative catalysis effect and color shift enhancement. The Cu@Eu-BTC dispersion-based method exhibits ultra-sensitive (limit of detection, LOD is 0.01 µM) and wide-range linear response (0.04-30 µM) to DA in real serum. More importantly, it has excellent selectivity for DA, even in the presence of epinephrine and norepinephrine analogs. Thus, this method realizes the accurate and precise quantification of DA in serum (recoveries: 98.1%-110.1%, relative standard deviation RSD < 4.6%). Next, Cu@Eu-BTC was prepared into paper microchip, which has good storage stability (RSD < 3.5%, n = 3) in four weeks and achieves point-of-care visual DA assay coupled with smartphone-assisted portable detection device. The MOF paper microchip-based method shows low sample consumption (30 µL), high accuracy and precision for the quantification of DA in serum (recovery of 92.9%-106.2%, RSD < 5.3%), and gets the same assay results as the MOF dispersion-based method (relative error ≤ 6.83%). To our knowledge, this is the first time to propose the catalytic fluorescence turn-on detection strategy of DA based on a MOF paper microchip.

Nonionic surfactants based hydrophobic deep eutectic solvents for liquid-liquid microextraction of Sudan dyes in tomato chili sauces.

A new type of high-density hydrophobic deep eutectic solvents (DESs) were synthesized with nonionic surfactants as hydrogen bond acceptors and hexafluoroisopropanol (HFIP) as hydrogen bond donor. Brij-35 was selected as the optimal nonionic surfactant for the preparation of Brij-35-HFIP-DES (molar ratio 1:20). A vortex-assisted DES-based liquid-liquid microextraction method was proposed for determination of Sudan dyes in tomato chili sauces. The whole pretreatment process only needs 5 min and 1.1 mL of organic solvent. The method with HPLC-DAD shows high efficiency (enrichment factors 89-176 and extraction rates 61.0-74.6%) and good performance with linearity (R ≥ 0.9997) in 0.04-2 µg g-1 range, detection limits of 0.0045-0.0118 µg g-1, recoveries of 91.6-104.5% and intra-/inter-day precision below 8.0%. A "DES in water in DES" aggregate microstructure was observed in DES-rich phase. The proposed method is simple, quick, eco-friendly, and suits for the efficient extraction and accurate determination of Sudan dyes in tomato chili sauces.

Multifunctional lanthanide metal-organic framework based ratiometric fluorescence visual detection platform for alkaline phosphatase activity.

A turn-on/off ratiometric fluorescence detection platform based on multifunctional lanthanide metal-organic framework (Ln-MOF) and an enzymatic cascade reaction is proposed for alkaline phosphatase (ALP) activity assay. L-phosphotyrosine is hydrolyzed to levodopa (L-dopa) by two steps of enzymatic reaction. L-dopa further reacts with naphthoresorcinol to produce carboxyazamonardine with strong emission at 490 nm. In this process, multifunctional Ln-MOF (Cu@Eu-BTC, BTC is the 1,3,5-benzenetricarboxylic acid) acts not only as a nanozyme to catalyze the fluorogenic reaction between L-dopa and naphthoresorcinol but also as a fluorescence internal standard. The emission of Cu@Eu-BTC at 620 nm is quenched by phosphate anions, and the dual-response ratiometric fluorescence (F490/F620) can be achieved. A good linear relationship was obtained between Δ(F490/F620) and ALP activity in the range 0.3-24 U L-1 with the detection limit of 0.02 U L-1. In addition, a portable assay tube was designed for visual and point-of-care testing of ALP activity by color variation (ratiometric chromaticity). Both the ratiometric fluorescence detection and the visual detection methods were successfully applied to monitor ALP activity in human serum samples with recovery between 95.5%-109.0% and 94.0%-110.1%, and relative standard deviation less than 8.1% and 9.5%, respectively. As far as we know, this is the first report of ALP activity assay assisted by multifunctional Ln-MOF.Graphical abstract.

A density-tunable liquid-phase microextraction system based on deep eutectic solvents for the determination of polycyclic aromatic hydrocarbons in tea, medicinal herbs and liquid foods.

A novel density-tunable liquid-phase microextraction (DT-LPME) system was developed with high-density deep eutectic solvents (DESs) as extractant and low-density organic solvents as emulsifier and density regulator. DES-rich phase was induced to form in the bottom or in the top by adjusting the emulsifier amount. This system was used to directly extract polycyclic aromatic hydrocarbons (PAHs) from liquid and solid foods, and the obtained DES-rich phase was easy to be collected for quantification. The method (LPME with HPLC-fluorescence detector) has linearity (R2 > 0.9974), detection limits of 0.6-4.2 ng L-1 for liquid foods and 0.05-0.35 ng g-1 for solid foods, recoveries of 86.2-114.9%, and intra-day/inter-day RSDs below 6.6%. The method was applied to detect PAHs in real samples, and the PAHs residue was found in honey and five solid foods. The DT-LPME method is simple, fast, green and suitable for direct extraction of analytes from both liquid and solid samples.

Rational Design of Dual-Emission Lanthanide Metal-Organic Framework for Visual Alkaline Phosphatase Activity Assay.

The alkaline phosphatase (ALP) activity assay is very significant for disease diagnosis and biomedical research. Lanthanide metal-organic framework (Ln-MOF) based fluorescence sensors have great application potential in ALP activity assays. However, it is critical but challenging to investigate the emission law of Ln-MOFs for revealing rational design principles and selecting an appropriate MOF. Here, we describe a reasonable design strategy for dual-emission Ln-MOFs based on theoretical calculations. This strategy combines Reinhoudt empirical rule, intramolecular charge transfer theory, and aggregation/coordination-induced emission theory; reveals the luminescence law of Ln-MOFs; and provides theoretical guidance for the rational design of dual-emission Ln-MOFs. On the basis of this strategy, we create a dual-emission Tb-MOF fluorescent probe used for ALP activity assay and investigate the detection mechanism. The probe shows ultrasensitive (limit of detection 0.002 mU mL-1) and selective response to ALP, and it suits for point-of-care visual detection coupled with a self-designed portable enzyme activity assay kit and smartphone-assisted visual device. The kit-based visual assay method can accurately quantify the activity of ALP in real serum samples (recovery >93%, and relative error is less than 6.8% compared with the results of fluorescence spectrometer-based method) and consumes only 25 µL of serum. In addition, a logical decoder based on the "dual-key unlocking strategy" is designed, providing a feasible solution for the development of intelligent ALP activity detection equipment. As far as we know, this is the first report of a theoretical calculation-guided versatile design strategy for dual-emission Ln-MOFs and a portable enzyme activity assay kit for visual detection.

Restricted access supramolecular solvent based magnetic solvent bar liquid-phase microextraction for determination of non-steroidal anti-inflammatory drugs in human serum coupled with high performance liquid chromatography-tandem mass spectrometry.

A hexafluroisopropanol (HFIP)-alkanol supramolecular solvent (SUPRAS) based magnetic solvent bar (MSB) liquid-phase microextraction (LPME) method was proposed for extraction of non-steroidal anti-inflammatory drugs (NSAIDs, including ketoprofen, naproxen, indomethacin and diclofenac) in human serum. The restricted access HFIP-alkanol SUPRAS was prepared by injecting a mixture of HFIP and alkanol into water. A stainless-steel needle was inserted into a piece of hollow fiber to prepare a magnetic bar. Then the magnetic bar was dipped in SUPRAS to impregnate the wall pores of the hollow fiber, followed by placing it into the serum sample for extraction. Only 4 µL of SUPRAS was consumed per bar. The MSB not only functioned for stirring, but also played the role of extraction and magnetic separation. Under the optimal extraction conditions (seven MSBs, extraction time 33 min and stirring rate 730 rpm), which was obtained by one variable-at-a-time and response surface methodology, the novel MSB-LPME was coupled with high performance liquid chromatography-tandem mass spectrometry to determine NSAIDs in human serum. The method showed a good linear relationship (correlation coefficients ≥ 0.9939). Method limits of detection and method limits of quantitation were in the range of 0.25-0.95 µg L-1 and 0.83-3.16 µg L-1, respectively. The recoveries for the spiked human serum samples ranged from 86.8% to 125.1% with intra- and inter-day relative standard deviations less than 9.2% and 18.1%, respectively. Moreover, the method did not require a protein precipitation step, and matrix effects of 72.8%-117.7% showed little interference with mass spectrometry detection, which was due to the double cleanup provided by the restricted access property of SUPRAS and the filtration capacity of hollow fiber. The HFIP-alkanol SUPRAS-based MSB-LPME method proved to be simple, highly efficient and environment-friendly for the pretreatment of serum/plasma.

Hexafluoroisopropanol-alkanol based high-density supramolecular solvents: Fabrication, characterization and application potential as restricted access extractants.

Hexafluoroisopropanol-alkanol (C6-C12) supramolecular solvents were proposed and their application potential as restricted access extraction solvents was assessed. Hexafluoroisopropanol acts as alkanol reverse micelle-forming agent and density-regulating agent for the supramolecular solvent synthesis. The formation of supramolecular solvent only needs a small percentage of hexafluoroisopropanol (<10% v/v for alkanol <5% v/v) and is almost not affected by the pH (2-11) and low ionic strength (NaCl <3%, w/v) of aqueous medium. The supramolecular solvents have higher density than water and consist of reversed micellar aggregates with irregular mesh structures and hydrophilic inner cavities, and the hydrophilic cavity size is obviously dependent on the hexafluoroisopropanol amount in the bulk system but almost not relevant to the alkanol amount. The hydrogen-bond and hydrophobic interactions of hexafluoroisopropanol with alkanol and the hydrogen-bond force between hexafluoroisopropanol and water play crucial roles in the formation of supramolecular solvent. The supramolecular solvents not only do not or slightly dissolve macromolecules (proteins, polysaccharides, and humic acid sodium), but also can effectively exclude them in extraction procedure; meanwhile, they can extract small molecules from complex samples with high extraction rate (even near 100% through optimization). The extraction mechanism involves the hydrophilic inner cavity size of supramolecular aggregates and the interactions (hydrogen-bond, hydrophobic) between supramolecular solvent and analytes. The suitability of supramolecular solvents as extractants was evaluated by extracting and determining chlorophenols in real water samples, coupled with high performance liquid chromatography-ultraviolet detector. The enrichment factors of 72-147 were obtained. Limits of detection were from 0.38 to 0.57 ng mL-1. The recoveries ranged from 96.0 to 107.9%, and intra-day and inter-day precisions were less than 4.0%. The novel hexafluoroisopropanol-alkanol supramolecular solvents have promising potential as restricted access extractants.

Double-Color Lanthanide Metal-Organic Framework Based Logic Device and Visual Ratiometric Fluorescence Water Microsensor for Solid Pharmaceuticals.

Water is one of the most widespread impurities and contaminants for pharmaceuticals and chemical products. A simple, fast and reliable water assay method is of high significance for the pharmaceutical and chemical manufacturing industries. In this work, lanthanide metal-organic framework Eu-dipicolinic acid/2-aminophthalic acid (Eu-DPA/PTA-NH2) was prepared as a double-color ratiometric fluorescent water sensor, which shows ultrasensitive (limit of detection 0.01% v/v) and linear broad-range (0-100% v/v) response to water. An innovative analytical device based on a one-to-two logic gate was constructed by using the water content and the two fluorescence responses as the input and output signals, respectively. The direct analysis of water content can be achieved by the four output types, NOT (0, 1), PASS 0 (0, 0), PASS 1 (1, 1), and YES (1, 0). Importantly, the metal-organic framework (MOF)-loaded fiber paper was prepared as a microsensor, and a water assay tube was designed for rapid water detection of solid pharmaceuticals via ratiometric chromaticity, coupled with a portable visual determination device. The paper-based microsensor is response-rapid (20 s), long-term stable (at least 30 days), and can achieve the accurate (relative error <9.8%) visual assay of trace water in solid pharmaceuticals. To our knowledge, this is the first time to report an MOF-based double-color ratiometric fluorescent water sensor, a water analytical logic device, and a paper-based water microsensor for point-of-care visual water assay in solid samples via ratiometric chromaticity.

Hexafluoroisopropanol-salt aqueous two-phase system for extraction and purification of chlorogenic acid from ramie leaves.

Hexafluoroisopropanol (HFIP) was used as a phase-separation solvent to develop novel alcohol-salt aqueous two-phase systems (ATPSs) with various salts. Phase diagram and effective excluded volume (EEV) study proved that HFIP has much better phase-separation ability compared to traditional small molecule alcohols (ethanol, isopropanol and n-propanol). Then, the HFIP-NaCl ATPS was applied for the extraction and purification of chlorogenic acid (CGA) from ramie leaves. Under the optimum conditions (2 M NaCl solution with pH 3.0, the volume ratio of NaCl solution to HFIP at 6, vortex time 5 s and centrifugation time 7 min), the extraction efficiency of CGA in the salt-rich phase was 99.3%, meanwhile the HFIP-rich phase could extract a large amount of impurities. Furthermore, the CGA product with the purity of 91.0% was obtained from the salt-rich phase by semi-preparative liquid chromatography and salt removal, and its chemical structure was identified. Compared with other ATPSs, the HFIP-NaCl ATPS consumed much less organic solvent and salt, but acquired much higher extraction efficiency and obvious impurity-removal effect. Therefore, the HFIP-based alcohol-salt ATPSs are promising in the extraction and purification of CGA and other polar compounds as well.

Hexafluoroisopropanol/Brij-35 based supramolecular solvent for liquid-phase microextraction of parabens in different matrix samples.

A novel supramolecular solvent (SUPRAS) based on hexafluoroisopropanol (HFIP)/Brij-35 was proposed for liquid-phase microextraction (LPME) of parabens in water samples, pharmaceuticals and personal care products. Brij-35 is a cost-effective and non-toxic non-ionic surfactant, but it has a high cloud point (>100 °C). HFIP, with the features of strong hydrogen-bond donor, high density and powerful hydrophobicity, was used as the cloud point-reducing agent and self-assembling and density-regulating solvent of Brij-35. Upon adding HFIP into the Brij-35 aqueous solution, the cloud point of Brij-35 was decreased to below room temperature, and the SUPRAS was formed in the bottom over a wide range of HFIP and Brij-35 concentrations at room temperature. The SUPRAS was composed of Brij-35, HFIP and water, having a density larger than water, and it showed a large spherical structure of positive micellar aggregates (2-8 µm). The HFIP/ Brij-35 SUPRAS-based LPME procedure was non-thermodependent and could be performed at room temperature with centrifugation using normal centrifuge tubes, being very simple. In the extraction of six parabens, the HFIP/ Brij-35 SUPRAS-based LPME method showed short extraction time (3.3 min), low solvent consumption (0.3 mL), and large enrichment factor (26-193). The method of HFIP/ Brij-35 SUPRAS-based LPME with HPLC-DAD gave good linearity for the quantification of parabens with correlation coefficients larger than 0.9990. The limits of detection based on a signal-to-noise ratio of 3 were from 0.042 to 0.167 µg L-1. The recoveries for the spiked real samples were in the range of 90.2-112.4% with relative standard deviation less than 8.9%. Except for tap water, one or several paraben (s) were detected in all the other real samples.