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Enhancing the surface area of stationary phase is essential in chromatographic science. In this work, nanoscale NiAl-layered double hydroxides (NiAl-LDHs) with flower-like structure was used as a platform for supporting the stationary phase. Then strong hydrophobic p-naphtholbenzein molecule was immobilized onto the LDHs layer as sorbent for stir bar sorptive extraction (SBSE). The flower-like LDHs layer significantly increased the extraction efficiency through increasing the specific surface area and immobilized amounts of stationary phase. In addition, the LDHs can also provide anion exchange ability, which expanded the application of this stir bar for analysis of not only hydrophobic but also anionic analytes. For improving the workability, a poly(ether ether ketone) (PEEK) jacket stir bar with detachable dumbbell-shaped structure was employed. The PEEK jacket with high mechanical strength and dumbbell-shaped structure improved the durability of stir bar and the detectable design allowed elution to be realized with less solvent that enhanced the enrichment factor. The proposed stir bar showed good performance for the extraction of multiple analytes including flavonoids, non-steroid anti-inflammatory drugs and chlorophenoxy acids. By coupling with high performance liquid chromatography-ultraviolet detection (HPLC-UV), the SBSE-HPLC-UV method was applied for the extraction of three active components including bavachin, isobavachalcone and bavachinin in Psoralea corylifolia L. herb with low limit detection of 0.01-0.02 ng/mL., Competing Interests: Declaration of competing interest Authors declare no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

MOF-1210(Zr/Cu) is a new heterometallic cluster-based metal-organic framework material as well as a promising solid phase extraction coating material with ordered spatial structure, permanent high porosity and large specific surface area. In this work, a novel MOF-1210(Zr/Cu) modified magnetic nanoparticles (MNPs) was successfully prepared for magnetic solid phase extraction (MSPE) of benzophenones, including 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3) and 2,2',4,4'-tetrehydroxybenzophenone (BP-6). The MOF-1210(Zr/Cu)-MNPs were synthesized in one step by a simple solvothermal method and showed high extraction efficiency towards analytes (with enrichment factors of 91-122). The extraction mechanism studies showed that the hydrogen bond interaction and coordination interaction between MOF-1210(Zr/Cu) and BPs played important roles during the extraction process. By coupling with HPLC, the MOF-1210(Zr/Cu)-MNPs-based MSPE-HPLC method showed wide linear range (0.1-300.0 ng·mL -1 ), good linearity (R ≥ 0.9982), excellent reproducibility (RSD ≤ 3.60%) and remarkable sensitivity (LODs in the range of 0.01-0.02 ng·mL -1 ). This method was also successfully applied to the extraction and detection of benzophenones in soil samples. Good recoveries were obtained (87.6%-113.8%) with RSDs less than 11.12%, which demonstrated the practicality of the proposed method., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Cotton fiber was proposed as a biodegradable support material. The properties like high specific area, hygroscopicity and adjustable shape make it be an idea substrate for solid phase extraction (SPE). In this work, inorganic layered double hydroxides (LDHs) were in situ immobilized onto cotton fiber through the linker of polydopamine as stationary phase. Uniform NiAl-LDHs crystal with nanostructure was observed on cotton fiber after one-step synthesis through urea hydrolytic method. The cotton fiber can not only increase the specific area and mass transfer rate, but also prevent aggregation and blocking of the freestanding LDHs crystal. Due to the electrostatic interaction and anion exchange features of LDHs, the prepared LDHs modified cotton fiber showed good extraction efficiency and selectivity towards fluoroquinolone drugs including norfloxacin, ciprofloxacin and enrofloxacin. After elution by 1 M NaOH, a simple acid-base neutralization method was proposed, so the natural elution can be directly analyzed by HPLC system. After optimizing the extraction parameters including adsorbent amount, sampling rate, sample volume, sample pH and eluent types and concentration, excellent extraction efficiency towards three fluoroquinolone drugs was obtained with high enrichment factors of 37-47. The adsorption capacity of LDHs modified cotton fiber was 21.18, 21.85 and 20.54 mg g -1 for norfloxacin, ciprofloxacin and enrofloxacin, which was almost twice as much as that of freestanding LDHs. The established method based on SPE-HPLC-FLC (fluorescence detector) technique exhibited good linearity (R 2 ≥ 0.995), low limits of detection (0.01 µg L -1 ) and good reproducibility (intra-day RSDs ≤ 3.89%). Moreover, this method has also been applied in analyzing fluoroquinolone drugs in chicken eggs and pork liver., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Layered double hydroxides (LDHs) are ideal sorbents for solid phase extraction (SPE) because of the excellent ion exchange capacity and high specific surface area. However, difficult elution of the analytes from the LDHs is a problem due to the strong ionic interaction between anions and LDHs. High concentrated NaOH solution is employed to elute the sample, but it not suitable for analyzing by HPLC. To solve this problem, a simple acid-base neutralization method was proposed after elution, and then the neutral samples were directly injected to HPLC for analysis. Nickel-aluminum layered double hydroxides (NiAl-LDHs) were synthesized by co-precipitation method and packed into a micro pipette tip for the extraction of three non-steroidal anti-inflammatory drugs (NSAIDs) including ketoprofen, naproxen and flurbiprofen from aqueous samples. After optimization of the experimental parameters such as the concentration of the NaOH, sample pH, sampling rate and sample volume, excellent extraction efficiency towards three NSAIDs was obtained with high enrichment factors of 28-32. A NiAl-LDHs based SPE-HPLC method was developed for quantitative analysis of NSAIDs, and the method showed low limits of detection (0.002-0.1ng/mL), good linearity (R 2 ≥0.9995) and good reproducibility (intraday RSD≤4.37%). The developed method was also applied to the analysis of three NSAIDs in spiked human plasma and rat plasma after oral administration, which demonstrated the practicality of the proposed method., (Copyright © 2017. Published by Elsevier B.V.)

The selective extraction of baicalin is important to its quality control especially when the matrices are complicated. In this work, a novel molecularly imprinted polymer was prepared for the selective extraction of baicalin in herbs. The molecularly imprinted polymer was synthesized by the copolymerization of 4-vinyl pyridine and ethylene glycol dimethacrylate in the presence of baicalin by a precipitation polymerization method. After the optimization of parameters for molecularly imprinted polymer preparation, including the functional monomer, porogen, sampling solvent, and washing solvent, good selectivity was obtained, with an imprinting factor of about 4, which is much better than that achieved by the bulk-polymerization method. The performances of the prepared molecularly imprinted polymers were systematically investigated, including adsorption kinetics, isotherm experiment, and Scatchard analysis. On the basis of the good adsorptive capability of the prepared molecularly imprinted polymer, it was also applied for the pretreatment of baicalin in Scutellaria baicalensis Georgi. The result showed that most of the matrices were removed and baicalin was selectively enriched., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Stainless steel wire (SSW) is a good substrate for stir bar sorptive extraction (SBSE). However, it is still a challenge to immobilize commonly used cross-linked polymers onto SSW. In this work, we present a new approach for immobilization of the cross-linked organic polymer onto SSW for jacket-free SBSE. A dopamine derivative was firstly synthesized; by introducing a mussel-inspired polydopamine process, a stable coating layer was finally generated on the surface of SSW. Secondly, the cross-linked polymer was synthesized on the polydopamine-modified SSW by using acetonitrile as the porogen, acrylamide (AA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker and 2,2'-azobis (2-methylpropionitrile) as the initiator. A diluted pre-polymerization solution was carefully prepared to generate a thin layer of the polymer. The prepared poly(EGDMA-AA)-modified stir bar showed high stability and good tolerance toward stirring, ultrasonication, organic solvents, and strong acidic and basic conditions. Morphology and structure characterization of coatings were performed by scanning electron microscopy and Fourier transform infrared spectra, respectively. The prepared poly(EGDMA-AA)-modified stir bar showed great extraction efficiency toward protoberberines, with enrichment factors of 19-42. An SBSE-HPLC method was also developed for quantitative analysis of protoberberines. The method showed low limits of detection (0.06-0.15 ng mL(-1)), wide linear range (0.5-400 ng mL(-1)), good linearity (R≥0.9980) and good reproducibility (RSD≤3.60% for intra-day, RSD≤4.73% for inter-day). The developed method has been successfully applied to determine protoberberines in herb and rat plasma samples, with recoveries of 88.53-114.61%., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Cotton fiber is a biodegradable material that possesses properties such as high specific area, adjustable shape, and hygroscopicity. In this work, organic polymer was directly in situ grown on the surface of cotton thread and packed into a poly(ether ether ketone) tube for online in‐tube solid‐phase microextraction. The novel strategy solves the problems like high backpressure and tedious optimization process of normal monolithic polymer‐based in‐tube solid‐phase microextraction capillary. The quaternary ammonium typed ionic liquid of 1‐allyl‐methylimidazolium chloride, 4‐vinylbiphenyl, and ethylene dimethacrylate were co‐polymerized and in situ grown on the surface of cotton thread as extraction phase. The solid‐phase microextraction tube showed excellent performance for the extraction of three nonsteroidal anti‐inflammatory drugs including ketoprofen, naproxen, and flurbiprofen due to the strong ion exchange and hydrophobic interactions. After online coupling with a high‐performance liquid chromatography system by six‐port valve, the method was applied for the quantitative analysis of nonsteroidal anti‐inflammatory drugs in human plasma samples showing good enrichment performance (enrichment factor between 263 and 279), high sensitivity, good linearity, and good reproducibility. [ABSTRACT FROM AUTHOR]

Abstract Herein a facile method for immobilization of zeolitic imidazolate frameworks (ZIFs) was developed. The ZIFs grew on electrochemically deposited zinc oxide (ZnO) layer while carbon fiber bundle served as substrate. The synthesized ZIFs-ZnO composite was packed into PEEK tube as sorbent for online solid phase microextraction (SPME)-HPLC-UV analysis of Sudan dyes. Good enrichment efficiency (200–461 fold), low limits of detection (0.002 ng mL−1) and wide linear ranges (0.02–20 ng mL−1, correlation coefficient > 0.9996) were achieved. The analytical method was demonstrated to be practical for analysis of Sudan dyes in environmental water samples with good recoveries (83.5%~95.0%). Graphical abstract Facile immobilization of zeolitic imidazolate framework on electrochemically deposited zinc oxide layer was achieved while the zinc oxide creatively acted as bridge between carbon fiber bundles and the zeolitic imidazolate framework. The modified carbon fiber bundles were packed into PEEK tube loop and connect with HPLC system for online solid-phase microextraction. Good extraction efficiency (between 200 and 461 fold) for Sudan dyes showed with the system. Application in spiked water samples exhibits high extraction efficiency and good recoveries. The feasible method is efficient and promising to introduce other metal-organic framework as efficient sorbent for online solid-phase microextraction. fx1 Highlights • Carbon fiber bundles with composite coating possess high extraction efficiency. • Facile introduction of zeolitic imidazolate framework as selective sorbent. • The zinc oxide acted as bridge between ZIFs and carbon fiber bundles. • Sudan dyes were efficiently extracted in acqueous solution. • A promising method to introduce other metal-organic frameworks as sorbent. [ABSTRACT FROM AUTHOR]

Abstract: A poly(vinylphenylboronic acid–ethylene glycol dimethacrylate) monolithic material incorporated with graphene oxide was synthesized inside a poly(ether ether ketone) tube. This tube with boronate affinity monolith was coupled with a high‐performance liquid chromatography system through a six‐port valve to construct an online solid‐phase microextraction with high‐performance liquid chromatography system. The performance of this solid‐phase microextraction with high‐performance liquid chromatography system was demonstrated by standard glycoprotein in aqueous samples, namely, horseradish peroxidase. Some parameters that affect the extraction performance were investigated, including sampling rate, pH of sample solution, and sampling volume. Under the optimized conditions, the developed method showed high extraction efficiency toward horseradish peroxidase. The addition of graphene oxide greatly increased the extraction efficiency of boronate affinity monolith for horseradish peroxidase. The limit of detection of the proposed method was as low as 0.01 μg/mL by using ultraviolet detection. The recognition specificity was also evaluated by analyzing the mixture of bovine serum albumin (nonglycoprotein) and horseradish peroxidase. The results showed that this material could selectively extract horseradish peroxidase from the mixture, indicating its good specificity toward glycoproteins. The proposed method was further applied for analyzing rat plasma samples spiked with horseradish peroxidase. Good recovery and repeatability were obtained. [ABSTRACT FROM AUTHOR]

A rational-designed conductive sorbent, poly(thiophene-3-boronic acid) electrochemically deposited on a carbon fiber bundle, was applied for boronate affinity extraction. The coated carbon fiber bundle packed into a poly(ether ether ketone) tube was then successfully used for online solid-phase microextraction-high-performance liquid chromatography analysis of cis-diol compounds. Three kinds of catecholamines (namely, adrenaline, noradrenaline, and dopamine) were used as the test analytes. Good extraction efficiency (more than 600-fold), low limits of detection (0.2 ng·mL for adrenaline, 0.1 ng·mL for noradrenaline and dopamine), and wide linear ranges were obtained. The method was demonstrated to be efficient for analysis of catecholamines in spiked plasma samples, with good recoveries in the range of 92.5-95.71%. This work exhibited several significant advantages, including ease of use, high specificity, and high extraction efficiency. It has been demonstrated that such an electrochemically synthesized sorbent has great potential for research involving cis-diol compounds. [ABSTRACT FROM AUTHOR]

A novel covalent organic framework based magnetic adsorbent was developed for magnetic solid phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs). Covalent organic framework-LZU1 (= Lan Zhou University-1) was covalently immobilized onto polyethyleneimine-functionalized magnetic nanoparticles (COF-LZU1@PEI@FeO), and the resulting material was characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The effects of the pH value of sample solution, percentage of acetonitrile, extraction time and sampling volume on MSPE of six PAHs were investigated. The COF-LZU1@PEI@FeO displays high extraction efficiency for the PAHs such as pyrene, benzo[a]pyrene, fluoranthene, benz[a]anthracene, benzo[a]fluorathene and dibenz[a,h]anthracene. Following desorption with acetonitrile, the PAHs were quantified by HPLC. The MSPE-HPLC method shows low limit of detection (0.2-20 pg mL), wide linear range and good reproducibility (relative standard deviations <4.4% for intra-day and inter-day precision). The method was successfully applied to determine PAHs in environmental samples. Good recoveries were obtained, ranging from 90.9 to 107.8% for water samples and 85.1 to 105.0% for soil samples. [ABSTRACT FROM AUTHOR]

A polymeric column that contains multiwalled carbon nanotubes-β-cyclodextrin composite was developed. The composite was wrapped into the poly(butyl methacrylate-ethylene dimethacrylate) monolith column (0.76 mm id and 10 cm in length). The column was then applied for the online solid-phase microextraction of psoralen and isopsoralen from Fructus Psoraleae. Following microextraction, the coumarins were quantified by high-performance liquid chromatography with C18 separation column and UV detection. The effects of sample flow rate, sample volume, and pH value were optimized. The method showed low limits of detection (20 pg/mL, S/N = 3) for both psoralen and isopsoralen. Finally the method was successfully applied to the determination of psoralen and isopsoralen in spiked herb extracts and rat plasma where it gave recoveries that ranged between 93.2 and 102.1%. The empty hydrophobic cavities of β-cyclodextrin and the hydrophobicity of multiwalled carbon nanotubes provided specific extraction capability for psoralen and isopsoralen. [ABSTRACT FROM AUTHOR]

Conductive composite films composed of poly (3, 4-ethylenedioxythiophene) (PEDOT) and sulfonated graphene were electrochemically deposited on carbon fiber bundle in aqueous solutions for solid phase microextraction (SPME). During the electro-polymerization process, negatively charged sulfonated graphene were doped in PEDOT layer and uniformly dispersed in the composite. The modified carbon fiber bundle worked as sorbent was then successfully applied to online SPME-HPLC-UV analysis of jasmonates in wintersweet flowers. High extraction efficiency (over 420-fold), low limits of detection (0.1 ng mL −1 for jasmonic acid and 0.01 ng mL −1 for methyl jasmonate) and wide linear ranges (0.5–5000 and 0.05–5000 ng mL −1 , R>0.9997) have been obtained. It has been demonstrated that this method can be well used for jasmonates analysis in fresh wintersweet flowers with good recoveries (92.4–98.9%). The results were confirmed by HPLC-MS method. [ABSTRACT FROM AUTHOR]

Novel covalent organic framework-1 modified magnetic nanoparticles (M-COF-1) were prepared for extraction of paclitaxel from rat plasma samples. Paclitaxel is an important anti-cancer drug in clinical chemotherapy. COF-1 was immobilized on the surface of magnetic nanoparticles by bio-inspired polydopamine functionalization method because polydopamine can supply catechol groups for supporting the immobilization of COF-1. The formation of M-COF-1 has been confirmed by Fourier transform infrared spectroscopy and transmission electron microscopy. A M-COF-1-based extraction method was developed for selective extraction of paclitaxel in aqueous solutions. Extraction conditions were investigated, including sample pH value, acetonitrile content, extraction time and sample volume. By combining with HPLC, this method showed a good linear range of 0.1–200 ng/mL with a low limit of detection of 0.02 ng/mL. The method was also applied for the pretreatment of paclitaxel in rat plasma samples, which showed effective enrichment efficiency and good clean-up capacity. Recoveries were calculated to be 99.4–103.7% with relative standard deviations less than 2.3%. [ABSTRACT FROM AUTHOR]

The authors show that carbon fiber bundles electrochemically modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is a viable sorbent for online solid-phase microextraction (SPME) of the sulfonamides (sulfadiazine, sulfadimidine and sulfamethoxazole) prior to their determination by HPLC. The fibers were packed in a tube loop made from polyether ether ketone (PEEK) that was coupled to the HPLC system for online SPME. Preconcentration factors can reach values of up to 300, and the limit of detection (at an S/N ration of 3) can be as low as 0.05 ng⋅mL. The method was applied to the analysis of the sulfonamides in spiked rat plasma with intra-day and inter-day RSDs of <3.33 and <4.57 %, and with recoveries in the range from 91.7 to 97.8 % in spiked plasma. The in-tube SPME was also applied to the determination of the 3 sulfonamides in rat plasma after oral administration (tablet powder) with high sensitivity. In addition to its efficient extraction, the PEEK tube based SPME has chemical and mechanical stability under even harsh conditions. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In this work, we developed a novel molecularly imprinted solid-phase microextraction with capillary electrophoresis method for the selective extraction and determination of protoberberines in complicated samples. The imprinted monolith was prepared in a micropipette tip-based device by using acrylamide as the functional monomer, ethyleneglyoldimethacrylate as the cross-linker and dimethylsulfoxide as the porogen, and exhibited an imprinting factor of 2.41 to berberine, 2.36 to palmatine and 2.38 to jatrorrhizine. Good capillary electrophoresis separation was achieved by using 20 mM phosphate buffer at pH 7 as running buffer with the addition of organic modifier of 10% methanol. Parameters such as sample pH value, sample flow rate and sample volume were investigated for imprinted monolith-based solid-phase microextraction. An imprinted solid-phase microextraction with capillary electrophoresis method was developed, the method showed a wide linear range (0.3-50 μg/mL), good linearity ( R2 ≥ 0.9947) and good reproducibility (relative standard deviations ≤ 0.73%), the limit of detection was as low as 0.1 μg/mL, which was lower than some reported methods based on capillary electrophoresis for protoberberines. The method has been applied for determination of three common protoberberines in Cortex Phellodendri Chinensis, by using a molecularly imprinted monolith as the selective sorbent, most of the matrices in the Cortex Phellodendri Chinensis sample were removed and three protoberberines were selectively enriched and well determined. [ABSTRACT FROM AUTHOR]

Two novel kinds of materials, β-cyclodextrin(CD)-modified silica and polyporous polymer particles, were prepared for solid phase extraction of methyl jasmonate (MeJA) in aqueous conditions. β-Cyclodextrin-modified silica was prepared by a sol-gel process and polyporous polymer was formed by 4-vinylpyridineas (4-VP) and ethyleneglycol dimethacrylate (EGDMA). For better extraction properties, preparation conditions were optimized. Bare silica particles were prepared for comparison of β-cyclodextrin-modified silica, and different kinds of monomers and the ratio of monomer to cross-linker were studied for polyporous polymer. To evaluate the usability of the two materials, extraction kinetics and isotherm curves were systematically studied. The extraction conditions were also optimized and both materials showed good extraction efficiency for MeJA, when evaluating by standard solution, enrichment factors of 56.5 and 75.3 were obtained for MeJA. Solid-phase extraction (SPE) -HPLC methods based on β-CD-modified silica and poly(4-VP-EGDMA) were also established for the determination of MeJA in aqueous samples. Good linearity was observed with R2 ≥ 0.998, and the low detection limits were found to be 2 and 3 ng/mL by UV detection. Finally, β-CD-modified silica and poly(4-VP-EGDMA) based SPE-HPLC methods have successfully been applied to determine MeJA in the wintersweet flower; recoveries were tested and found to be in the range of 79.0 to 87.3%. [ABSTRACT FROM PUBLISHER]

Abstract: A novel and simple poly(ether ether ketone) (PEEK) tube-based solid-phase microextraction (SPME)-HPLC method was developed in this work. A mussel inspired polydopamine method was used to functionalize the chemically resistant surface of PEEK tube and a poly(acrylamide–ethylene glycol dimethacrylate) monolith was synthesized inside the PEEK tube and chemically bonded with its surface. The stability of the polydopamine layer was investigated and found to be well enduring to most of commonly used organic solvents and strong acidic conditions. The PEEK tube-based monolith was coupled with HPLC system through a six-port valve, and the performance of the online SPME–HPLC system was demonstrated by analyzing three protoberberine alkaloids in aqueous samples, namely jatrorrhizine (Jat), palmatine (Pal) and berberine (Ber). These analytes were well extracted and separated within 10min, and enrichment factors of about 400 were obtained. The limit of detection of the proposed method was decreased to 0.01ng/mL by using UV detection. Finally, the online SPME–HPLC method was applied for determining Jat, Pal and Ber in rat plasma samples. Reproducibility was obtained by evaluating the intra- and inter-day precisions with RSDs less than 6.1% and 8.5%, respectively, and recoveries of the analytes in spiked plasma samples ranged from 89.8% to 96.7%. The proposed method was also applied to determine the concentration of Jat, Pal and Ber in rat plasma after oral administration of Cortex Phellodendri Chinensis. [Copyright &y& Elsevier]

Abstract: A novel berberine-imprinted polymer (MIP) monolith was prepared for extraction of berberine in aqueous medium. The MIP monolith was prepared inside a polypropylene micropipette tip by using dimethylsulfoxide as porogen, acrylamide (AA) as functional monomer and ethyleneglyol dimethacrylate (EGDMA) as cross-linker. Polymerization conditions were optimized and good permeability and selectivity was obtained when the ratio of berberine/AA/EGDMA was 1:5:30. Cross-reaction was also studied by three compounds (palmatine, coptisine, and jatrorrhizine) with similar structure. A molecularly imprinted micro solid-phase extraction (MI-μ-SPE) method was developed for selective extraction of berberine in aqueous solutions. Extraction parameters were investigated, such as sample pH value, sample flow rate, sample volume and elution solvent. By combining with HPLC/UV, MI-μ-SPE method showed a good linear range of 3–800ng/mL with a low limit of detection limit of 1.0ng/mL. The method was also applied for the pretreatment of berberbine in human plasma and urine samples. The result showed that proteins and other biological matrix were successfully eliminated and berberine was selectively enriched. Recoveries were tested in plasma and urine samples, and calculated to be 90.6–103.2% with relative standard deviations less than 4.7%. [Copyright &y& Elsevier]

Highlights • A novel cotton@PDA@UiO-66 was synthesized with a simple method. • Cotton@PDA@UiO-66-based SPME showed high extraction efficiency towards NSAIDs. • The SPME-HPLC method was developed to detect NSAIDs in swine muscle sample. • This method exhibited high sensitivity, wide linearity and good repeatability. Abstract A novel metal-organic framework UiO-66-modified cotton was prepared and applied to solid phase microextraction of non-steroidal anti-inflammatory drugs, namely ketoprofen, naproxen and flurbiprofen. UiO-66 was immobilized onto the surface of cotton by a polydopamine functionalized method. The resultant cotton@PDA@UiO-66 was characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The solid phase microextraction conditions were optimized, including sampling flow rate, formic acid content of the eluent, pH value of sample solution, NaCl content and sample volume. By combining with HPLC, this method showed high extraction efficiency (the enrichment factors of ketoprofen, naproxen and flurbiprofen were 44, 49 and 45, respectively), wide linear range (0.1–500 ng/mL), good linearity with R ≥ 0.9996 and satisfactory sensitivity (LODs ≤ 0.03 ng/mL, LOQs ≤ 0.1 ng/mL), as well as good reproducibility (RSD ≤ 4.51%). This method was also successfully applied to extraction of NSAIDs in swine muscle sample. Good recoveries were obtained, ranging from 88.54% to 95.7% with relative standard deviations less than 3.77%. [ABSTRACT FROM AUTHOR]

Polymer monolithic column based on a green deep eutectic solvent (DES) was prepared for in-tube solid phase microextraction of non-steroidal anti-inflammatory drugs (NSAIDs) in aqueous samples. DES composed of choline chloride and itaconic acid was adopted as functional monomer to synthesize a polymeric monolith inside polydopamine-functionalized poly(ether ether ketone) (PEEK) tube. The obtained monolithic column was characterized with fourier transform infrared spectrometry, X-ray photoelectron spectrometer and field emission scanning electron microscope. An online SPME-HPLC method was developed by connecting the PEEK tube to the HPLC system. Parameters including sampling rate, desorption time, sample pH value and sample volume that can affect the performance of this method were investigated. Under the optimized conditions, the proposed SPME-HPLC method showed high extraction efficiency (enrichment factors about 100), good linearity (R ≥ 0.9997) and good reproducibility (relative standard deviation < 4.32%) for determination of three NSAIDs in aqueous solution. The limits of quantification were found to be in a range of 0.05–0.25 ng mL −1 . The SPME-HPLC method was also successfully applied to detect NSAIDs in lake water and human plasma samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • MOF-801 was firstly applied in MSPE. • MOF-801 modified PEI-MNPs (PEI-MNPs@MOF-801) was prepared by a solvothermal method. • PEI-MNPs@MOF-801 exhibited high extraction efficiency for PTL treatment drugs. • This method showed high sensitivity, good linearity and excellent reproducibility. • The method was successfully applied in human plasma samples. A novel magnetic solid-phase extraction (MSPE) method based on metal organic framework-801 (MOF-801) modified magnetic nanoparticles (noted as PEI-MNPs@MOF-801) was successfully prepared for the extraction of preterm labor treatment drugs (including indometacin, acemetacin and sulindac) from human plasma sample. MOF-801, a new kind of porous coordination polymer composed of Zr4+ and fumaric acid, was modified on the surface of synthesized polyethyleneimine magnetic nanoparticles (PEI-MNPs) through amidation reaction. The obtained PEI-MNPs@MOF-801 was characterized with Fourier-transformed infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. A MSPE-HPLC-UV method was developed by coupling PEI-MNPs@MOF-801 with HPLC system. Several parameters that affect the extraction efficiency including acetonitrile content, NaCl content, extraction time and sample volume were investigated. Under optimum conditions, the proposed MSPE-HPLC-UV method showed high extraction efficiency (enrichment factors between 96–118), good linearity with R ≥ 0.9987, excellent reproducibility (RSD ≤ 4.30 %) and low limits of detection in the range of 0.03−0.05 ng/mL. This method was also successfully applied to the extraction of indometacin, acemetacin and sulindac in human plasma samples and good recoveries were obtained. [ABSTRACT FROM AUTHOR]

Mass spectrometry has become a powerful tool in the field of bioanalysis. The combination of capillary electrophoresis with mass spectrometry (CE-MS) offers fast and high-resolution separation, sensitive and selective detection with small sample volumes, which is suitable for cell analysis. Here, we review the recent technical development of CE, MS and hyphenated strategies as well as their potential in cell analysis. In particular, we discuss the multiple MS compatible CE modes including capillary zone electrophoresis, capillary isoelectric focusing, capillary isotachophoresis, micellar electrokinetic capillary chromatography and capillary electrochromatography for achieving better separation efficiency and selectivity before MS detection. For enhancing the sensitivity of CE-MS, several online preconcentration methods including dynamic pH junction, transient isotachophoresis and solid phase extraction are also reviewed and discussed. We also summarize the existing applications of CE-MS in cell analysis including cell biomacromolecule analysis, cell metabolism and single cell analysis. • CE-MS is a suitable and promising candidate for cell analysis. • CE-MS including technique development and applications in cell analysis is reviewed. • CE-MS interfaces, different ionization methods and CE modes are discussed. • Applications in biomacromolecule analysis, cell metabolism and single cell analysis were reviewed. [ABSTRACT FROM AUTHOR]

• Three amino-MOFs coated cottons were prepared via a facile cysteine-triggered in situ growth strategy. • Prepared adsorbents showed satisfactory extraction performance for three NSAIDs. • Hydrogen bonding, electrostatic and π-π interaction contributed to the adsorption. • Established method was used for the analysis of NSAIDs in human plasma samples. The determination of blood concentration of non-steroidal anti-inflammatory drugs (NSAIDs) is highly desired in clinical practice. In this work, three amino bearing metal-organic frameworks (amino-MOFs) coated cotton fibers were prepared using a facile cysteine-triggered in situ growth strategy and proposed as in-tip solid-phase microextraction (in-SPME) adsorbents for efficient extraction of non-steroidal anti-inflammatory drugs from human plasma. The self-made adsorbents exhibited satisfactory extraction performance toward three NSAIDs including diclofenac sodium, ketoprofen and flurbiprofen. Under the optimized conditions, the established method exhibited satisfactory enrichment performance, low limits of detection and excellent extraction efficiency. Good reproducibility, wide linear range, excellent linearity and satisfactory sensitivity were obtained in the experiment. The method was also used for the enrichment and determination of NSAIDs in human plasma samples. Good recoveries were obtained, ranging from 66.5% to 98.9% with relative standard deviations less than 6.62%. The good performance of amino-MOFs was due to the synergistic effects arising from grafted charged amino groups within ordered pores of suitable size, leading to strong affinity towards guest molecules. Electrostatic interaction, hydrogen bond and π-π interaction played a vital role in the extraction of NSAIDs. This report indicated the potential of amino-MOFs as efficient adsorbents for the determination of NSAIDs from human plasma. [ABSTRACT FROM AUTHOR]

In this work, we interestingly happened to observe the adsorption of stainless steel sample loop of HPLC. The adsorptive behaviors of the stainless steel loop toward different kinds of compounds were studied, including polycyclic aromatic hydrocarbons (PAHs), halogeno benzenes, aniline derivatives, benzoic acid derivatives, phenols, benzoic acid ethyl ester, benzaldehyde, 1-phenyl-ethanone and phenethyl alcohol. The adsorptive mechanism was probably related to hydrophobic interaction, electron-rich element–metal interaction and hydrogen bond. Universal adsorption of stainless steels was also testified. Inspired by its strong adsorptive capability, bare stainless steel loop was developed as a modification-free in-tube device for solid-phase microextraction (SPME), which served as both the substrate and sorbent and possessed ultra-high strength and stability. Great extraction efficiency toward PAHs was obtained by stainless steel loop without any modification, with enrichment factors of 651–834. By connecting the stainless steel loop onto a six-port valve, an online SPME–HPLC system was set up and an SPME–HPLC method has been validated for determination of PAHs. The method has exceptionally low limits of detection of 0.2–2 pg/mL, which is significantly lower than that of reported methods with different kinds of sorbents. Wide linear range (0.5–500 and 2–1000 pg/mL), good linearity ( R 2 ≥ 0.9987) and good reproducibility (RSD ≤ 2.9%) were also obtained. The proposed method has been applied to determine PAHs in environmental samples. Good recoveries were obtained, ranging from 88.5% to 93.8%. [ABSTRACT FROM AUTHOR]

Abstract: A fully automated microextraction by packed sorbents (MEPS) coupled with large volume injection gas chromatography–mass spectrometry (GC–MS) has been developed for the determination of eight polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Naphthalene (Nap), pyrene (Pyr), anthracene, acenaphthylene, phenanthrene, fluoranthene (Flr), fluorene and acenaphthene were the PAHs studied. The performance of the microextraction-GC–MS protocol was compared with solid phase extraction (SPE) and GC–MS analysis. Under optimized experimental conditions, the methods were linear for all analytes in the following ranges: 0.05–2.0μgL−1 (MEPS) and 0.25–10.0μgL−1 (SPE). The correlation coefficients (R 2) were in the range 0.9965–0.9997 (MEPS) and 0.9978–0.9998 (SPE) for all the analytes. Limits of detection (LODs) for 2mL samples (MEPS) ranged from 0.8ngL−1 to 8.2ngL−1. LODs for 50mL samples (SPE) were between 4.8ngL−1 and 35.9ngL−1. The two methods were successfully applied to the determination of the 8 PAHs in environmental waters, with recoveries in the range of 70–117% (MEPS) and 72–134% (SPE) for a real spiked sample. The two sample preparation processes showed good repeatabilities with intra-day relative standard deviations below 14.0% (MEPS) and 14.6% (SPE). Nap, Flr and Pyr were found in a river water sample. [Copyright &y& Elsevier]