•The basalt fiber with excellent environmental and chemical properties was first used for in-tube SPME.•The polyaniline coating was first grown on the basalt fiber by in situ hydrothermal.•This method showed high extraction efficiency compared with other reported methods.•The fibers-in-tube SPME extraction device is shown good durability and repeatability.A facile, low cost, sensitive and environmentally friendly polyaniline (PANI) coating was prepared onto the basalt fibers (BFs) by in situ hydrothermal growth method. PANI functionalized BFs were placed into a poly(ether ether ketone) (PEEK) tube as a fibers-in-tube solid-phase microextraction (SPME) device. The extraction and analysis processes were carried out by connecting it to high performance liquid chromatography (HPLC). Three ultraviolet filters including 2-hydroxy-4-methoxybenzophenone, phenyl salicylate and 2,4-dihydroxybenzophenone were employed as model analytes. Under the optimal extraction and desorption conditions, online in-tube SPME-HPLC analysis method was established and afforded satisfactory enrichment factors (1323–1555), wide linear ranges (0.06–100 μg L−1) with correlation coefficients ranging from 0.9995 to 0.9999, low limits of detection (0.02–0.05 μg L−1) and acceptable extraction repeatability (RSD < 7.8%, n = 6) and preparation repeatability (RSD < 9.7%, n = 3). The proposed method was successfully applied to the determination of the three ultraviolet filters in two environmental water samples.

•An organically modified silica aerogel was developed as the coating for IT-SPME.•Basalt fiber was modified with aerogel coating by a facile method.•IT-SPME device was easily connected into HPLC for online analysis.•IT-SPME device showed good durability, repeatability and extraction selectivity.•Online analysis method was built and applied to the detection of estrogens in water samples.Aerogels have received considerable attentions because of its porous, high specific surface, unique properties and environmental friendliness. In this work, an organically modified silica aerogel was functionalized on the basalt fibers (BFs) and filled into a poly(ether ether ketone) (PEEK) tube, which was coupled with high performance liquid chromatography (HPLC) for in-tube solid-phase microextraction (IT-SPME). The aerogel was characterized by scanning electron microscopy (SEM) and fourier transform infrared spectrometry (FT-IR). The extraction efficiency of the tube was systematically investigated and shown enrichment factors from 2346 to 3132. An automated, sensitive and selective method was developed for the determination of five estrogens. The linear range was from 0.03 to 100 μg L−1 with correlation coefficients (r) higher than 0.9989, and low detection limits (LODs) were 0.01–0.05 μg L−1. The relative standard deviations (RSDs) for intra-day and inter-day were less than 4.5% and 6.7% (n = 6), respectively. Finally, the analysis method was successfully applied to detect estrogens in sewage and emollient water samples.

•A CL biosensor for Lys was obtained coupled with SMIP based on ILs-Fe3O4@DA/GO/β-CD.•Absorption capacity of ILs-Fe3O4@DA/GO/β-CD-SMIP to Lys reached up to 101 mg/g.•The adsorption equilibrium was reached within 10 min.•Adsorption model followed Langmuir isotherm.•The CL system was luminol, K3[Fe(CN)6] and NaOH solutions.In this work, ionic liquid modified Fe3O4@dopamine/graphene oxide/β-cyclodextrin (ILs-Fe3O4@DA/GO/β-CD) was used as supporting material to synthesize surface molecularly imprinted polymer (SMIP) which then was introduced into chemiluminescence (CL) to achieve an ultrasensitive and selective biosensor for determination of lysozyme (Lys). ILs and β-CD was applied to provide multiple binding sites to prepare Lys SMIP and Fe3O4@DA was designed to make the product separate easily and prevent the aggregation of GO which could improve absorption capacity for its large specific surface area. The ILs-Fe3O4@DA/GO/β-CD-SMIP showed high adsorption capacity (Q = 101 mg/g) to Lys in the adsorption isotherm assays. The adsorption equilibrium was reached within 10 min for all the concentrations, attributing to the binding sites situated exclusively at the surface, and the adsorption model followed Langmuir isotherm. Under the suitable CL conditions, the proposed biosensor could response Lys linearly in the range of 1.0 × 10−9–8.0 × 10−8 mg/mL with a detection limit of 3.0 × 10−10 mg/mL. When used in practical samples in determination of Lys, the efficient biosensor exhibited excellent result with the recoveries ranging from 94% to 112%.

A trace-level chemiluminescent (CL) sensor for the determination of phenacetin, utilising CdTe quantum dots@luminol (QDs@luminol) for signal amplification, based on a chitosan/magnetic graphene oxide-molecularly imprinted polymer (CsMG-MIP) as a biological recognition material was fabricated. CdTe QDs@luminol, which was used in the preparation process for the sensor, could amplify the signal of the CL sensor through chemiluminescence resonance energy transfer (CRET) while reducing the consumption of luminol. The CsMG-MIP, taking full advantage of the abundant hydroxyl and amino groups in chitosan which provide a lot of sites for the formation of hydrogen bonds in SMIP, using graphene oxide to improve the adsorption capacity and Fe3O4 nanoparticles to make the preparation of the recognition unit simple and easy, was introduced into the CL sensor. Under the optimized conditions of the CL sensor, phenacetin could be assayed in the range of 3.0 × 10−9–3.0 × 10−7 mol L−1 with a detection limit of 8.2 × 10−10 mol L−1 (3δ). With the advantages of amplifying the CL signal through CRET and reducing the consumption of luminol simultaneously, the sensor was successfully applied to the determination of trace-level phenacetin in real samples with a high selectivity and with the reagent economized.

Mainly, ionic liquid (IL) was used as functional bridging agent and surface modifier to obtain phenylboronic acid modified-IL functionalized GO@Fe3O4 nanoparticles (GO@Fe3O4@IL/PBA) with reversible covalent binding properties with cis-diol containing compounds particularly. Then GO@Fe3O4@IL/PBA with the properties of high surface area and easy separation was designed as supporting material to prepare Horseradish Peroxidase (HRP) SMIP which then was characterized by SEM, XRD and FTIR. The adsorption capacity of GO@Fe3O4@IL/PBA-SMIP to HRP was researched to be 8.8 g/g, and the adsorption model and adsorption kinetics of GO@Fe3O4@IL/PBA-SMIP to HRP followed Langmuir adsorption isotherm and pseudo second-order model while the washing process was superior with acetic acid than NaOH solutions. Possessing the merit of improving selectivity, GO@Fe3O4@IL/PBA-SMIP was introduced into CL biosensor which could linearly respond to HRP in the range of 1.0 × 10−4–8.0 × 10−3 mg/mL with a detection limit 2.9 × 10−5 mg/mL. Finally, the proposed GO@Fe3O4@IL/PBA-SMIP-CL biosensor was used to detect the HRP in samples with satisfied results and the recoveries were ranged from 87% to 107%.

•The CL signal was amplified by intramolecular CRET in CdTe QDs@luminol•Chitosan/graphene oxide-magnetite-molecular imprinted polymers were introduced•Detection limit was lower than conventional methods for CL sensingA sensitive chemiluminescence (CL) sensor based on chemiluminescence resonance energy transfer (CRET) in CdTe quantum dots@luminol (CdTe QDs@luminol) nanomaterials combined with chitosan/graphene oxide-magnetite-molecularly imprinted polymer (Cs/GM-MIP) for sensing chrysoidine was developed. CdTe QDs@luminol was designed to not only amplify the signal of CL but also reduce luminol consumption in the detection of chrysoidine. On the basis of the abundant hydroxy and amino, Cs and graphene oxide were introduced into the GM-MIP to improve the adsorption ability. The adsorption capacities of chrysoidine by both Cs/GM-MIP and non-imprinted polymer (Cs/GM-NIP) were investigated, and the CdTe QDs@luminol and Cs/GM-MIP were characterized by UV–vis, FTIR, SEM and TEM. The proposed sensor can detect chrysoidine within a linear range of 1.0 × 10− 7 - 1.0 × 10− 5 mol/L with a detection limit of 3.2 × 10− 8 mol/L (3δ) due to considerable chemiluminescence signal enhancement of the CdTe quantum dots@luminol detector and the high selectivity of the Cs/GM-MIP system. Under the optimal conditions of CL, the CdTe QDs@luminol-Cs/GM-MIP-CL sensor was used for chrysoidine determination in samples with satisfactory recoveries in the range of 90-107%.

A chemiluminescence (CL) sensor with high sensitivity and selectivity has been developed for the determination of Ribonuclease A (RNase A). A new material Fe3O4/multi-walled carbon nanotubes/SiO2 (Fe3O4/MWCNTs/SiO2) was introduced into this sensor as a supporting material to prepare a surface molecular imprinting polymer (SMIP). In this work, Fe3O4 not only served as a backbone material in the preparation of the RNase A SMIP, but also as a separation reagent to allow the easy collection of the SMIP complex. Carbon nanotubes and SiO2 were also used as supporting materials to prepare SMIP for their large specific surface area. The Fe3O4/MWCNTs/SiO2 nanocomposite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. The adsorption ability of the Fe3O4/MWCNTs/SiO2-SMIP was calculated to be 102 mg g−1, which demonstrated the excellent recognition and adsorption ability of the imprinting cavities situated at or in the proximity of the surface of the Fe3O4/MWCNTs/SiO2. Under optimal conditions, the linear range of the sensor extended from 1.0 × 10−9 mg mL−1 to 1.0 × 10−7 mg mL−1 for RNase A and the detection limit was 3.2 × 10−10 mg mL−1 (3δ). The proposed sensor was successfully applied for the determination of RNase A in biological samples with recoveries from 93% to 105%.

In this report, a sensitive and selective chemiluminescence (CL) biosensor for bovine serum albumin (BSA) coupled with a surface molecularly imprinted polymer nanocomplex using β-cyclodextrin/chitosan–magnetic graphene oxide as backbone material (β-CD/Cs–MGO–SMIP) was investigated. The material β-CD/Cs–MGO combined with β-cyclodextrin, chitosan and graphene oxide was used to provide multiple imprinting sites and a large surface area was characterized by SEM, XRD and FTIR. It was found that β-CD/Cs–MGO–SMIP followed the Langmuir isotherm equation and pseudo-second order sorption kinetics when binding the template. This material demonstrated fast mass transfer, a promoted rate of removal of the biomacromolecule and excellent recognition and adsorption ability for the imprinting cavities situated at the surface of β-CD/Cs–MGO, which enabled easy access to BSA. Subsequently, a highly sensitive CL biosensor for BSA was proposed based on the strong recognition effect between β-CD/Cs–MGO–SMIP and BSA which led to a high selectivity of the sensor, and the proposed biosensor could assay in the range 5.0 × 10−7 to 1.0 × 10−4 mg mL−1 with a detection limit of 1.1 × 10−7 mg mL−1. The obtained recoveries were between 94% and 106% when determining samples.

•Graphene coating was bonded onto a stainless steel wire as a SPME fiber.•Electroless plating and layer-by-layer fabrication were used to prepare the fiber.•SPME-GC method provided high sensitivity and wide linear range for n-alkanes.•The fiber exhibited excellent extraction efficiency and high stability.•The chemical bond between coating and wire improved the stability of the fiber.A graphene coating bonded onto stainless steel wire was fabricated and investigated as a solid-phase microextraction fiber. The coating was characterized by scanning electron microscopy and energy-dispersive X-ray spectrometer. The coating with rough and crinkled structure was about 1 μm. These characteristics were helpful for promoting extraction. Using five n-alkanes (n-undecane, n-dodecane, n-tridecane, n-tetradecane and n-hexadecane) as analytes, the fiber was evaluated in direct-immersion mode by coupling with gas chromatography (GC). Through optimizing extraction and desorption conditions, a sensitive SPME-GC analytical method was established. SPME-GC method provided wide linearity range (0.2–150 μg L−1) and low limits of determination (0.05–0.5 μg L−1). It was applied to analyze rain water and a soil sample, and analytes were quantified in the range of 0.85–1.96 μg L−1 and 0.09–3.34 μg g−1, respectively. The recoveries of samples spiked at 10 μg L−1 were in the range of 90.1–120% and 80.6–94.2%, respectively. The fiber also exhibited high thermal and chemical stability, due to the covalent bonds between graphene coating and wire, and the natural resistance of graphene for thermal, acid and basic conditions.

•Graphene oxide-molecular imprinted polymers were introduced.•Silanized Fe3O4 nanoparticles were employed.•Detection limit was lower than conventional methods.•The adsorption capacity was improved.Based on silanized magnetic graphene oxide-molecularly imprinted polymer (Si-MG-MIP), a sensitive and selective chemiluminescence sensor for dopamine measurement was developed. Si-MG-MIP, in which silanes was introduced to improve the mass transfer, graphene oxide was employed to improve absorption capacity, Fe3O4 nanoparticles were applied for separation easily and molecularly imprinted polymer was used to improve selectivity, demonstrated the advantages of the sensor. All the composites were confirmed by SEM, TEM, XRD and FTIR. Under the optimal conditions of chemiluminescence, dopamine could be assayed in the range of 8.0–200.0 ng/mL with a correlation coefficient of linear regression of 0.9970. The detection limit was 1.5 ng/mL (3δ) and the precision for 11 replicate detections of 80.0 ng/mL dopamine was 3.4% (RSD). When the sensor was applied in determining dopamine in actual samples, recovery ranged from 94% to 110%, which revealed that the results were satisfactory.

A novel chemiluminescence (CL) sensor for the on-site determination of vanillin using the system of luminol–KMnO4–NaOH based on a magnetic graphene oxide molecularly imprinted polymer (GM-MIP) is described. The vanillin–GM-MIP system, which has the merits of easy separation, high selectivity and a large amount of adsorption, was synthesized as a vanillin recognition material in the CL analysis, where the GM-MIP column was placed ahead of the pump in the experimental setup so as to increase the selectivity of CL analysis. The GM-MIP was characterized by SEM, XRD, TEM and FTIR, and also for its adsorption ability, selectivity and reusability. The GM-MIP-CL sensor responded linearly to the concentration of vanillin over the range 3.3 × 10−7 to 1.2 × 10−5 mol L−1 with a detection limit of 1.1 × 10−7 mol L−1 (3δ). The RSD was 3.9%, and on the basis of speediness and high selectivity the sensor showed a great improvement in selectivity and adsorption capacity. Finally, the sensor was applied to the determination of vanillin in practical samples, and the recoveries were between 6% and 8%. The sensor was an easily producible, simple automatic column packing with high selectivity.

A novel stationary phase based on quinolinium ionic liquid-modified silica was prepared and evaluated for high-performance liquid chromatography. The stationary phase was investigated via normal-phase (NP), reversed-phase (RP), and anion-exchange (AE) chromatographic modes, respectively. Polycyclic aromatic hydrocarbons, phthalates, parabens, phenols, anilines, and inorganic anions were used as model analytes in chromatographic separation. Using the newly established column, organic compounds were separated successfully by both NP and RP modes, and inorganic anions were also separated completely by AE mode. The obtained results indicated that the stationary phase could be applied in different chromatographic modes, with multiple-interaction mechanism including van der Waals forces (dipole–dipole, dipole–induced dipole interactions), hydrophobic, π–π stacking, electrostatic forces, hydrogen bonding, anion-exchange interactions, and so on. The column packed with the stationary phase was applied to analyze phthalates and parabens in hexane extracts of plastics. Tap water and bottled water were also analyzed by the column, and nitrate was detected as 20.1 and 13.8 mg L−1, respectively. The results illustrated that the stationary phase was potential in practical applications.

A novel flow injection chemiluminescence (FI-CL) sensor for the determination of sulfamethoxazole (SMZ) was established which using chitosan/graphene oxide-molecularly imprinted polymers (CG-MIP) as recognition element. The SMZ-CG-MIP was synthesized in acetone as solvent and chitosan/graphene oxide for support, using acrylamide as functional monomer, ethylene glycol dimethacrylate as cross-linker and 2,2-azobisisobutyronitrile as initiator. The CG-MIP showed satisfactory recognition capacity for the SMZ. Then the synthesized CG-MIP was employed as recognition by packing into a lab-made tube connected in FI-CL analyzer to establish a novel CL sensor respectively. The CL intensity responded linearly to the concentration of SMZ in the range 1.0 × 10−7 mol/L to 2.3 × 10−3 mol/L with a detection limit of 2.9 × 10−8 mol/L (3σ), which is lower. The relative standard deviation for the determination of 4.0 × 10−4 mol/L of SMZ was 1.92% (n = 11). The sensor is reusable and has a great improvement in sensitivity and selectivity for CL analysis which applied to the determination of SMZ in drug samples.Highlights► A novel chemiluminescence sensor was described. ► Chitosan/graphene oxide-molecularly imprinted polymer was used. ► The adsorption capacity was improved using chitosan/graphene oxide.

Magnetic β-cyclodextrin–chitosan/graphene oxide materials (MCCG) were fabricated through a facile chemical route and their application as excellent adsorbents for dye removal were also demonstrated. The characteristics results of FTIR, SEM, TEM and XRD showed that MCCG was successfully prepared. The results showed that, benefiting from the surface property of graphene oxide, hydrophobicity of β-cyclodextrin, the abundant amino and hydroxyl functional groups of chitosan, and from the magnetic property of Fe3O4, the adsorbent possesses quite a good and versatile adsorption capacity to the dye under investigation, and can be easily and rapidly extracted from water by magnetic attraction. Most importantly, the adsorbent can be easily and efficiently regenerated for reuse with hardly any compromise of the adsorption capacity. The adsorption kinetics, isotherms and thermodynamics were investigated to indicate that the kinetics and equilibrium adsorptions were well-described by pseudo-second-order kinetic and Langmuir isotherm model, respectively. The thermodynamic parameters suggested that the adsorption process was spontaneous and endothermic in nature. The inherent advantages of the nano-structured adsorbent, such as adsorption capacity, easy, handy operation, rapid extraction, and regeneration, may pave a new, efficient and sustainable way towards highly-efficient dye pollutant removal in water and wastewater treatment.Graphical abstractHighlights► Magnetic β-cyclodextrin–chitosan/graphene oxide was first synthesized as a novel adsorbent to adsorb methylene blue. ► The adsorption capacity of the biosorbent is higher than other adsorbents. ► It shows the facile and fast separation process of the biosorbent. ► Desorption studies were performed to evaluate adsorbent efficiency.

Magnetic chitosan/graphene oxide (MCGO) materials were fabricated through a facile and fast process and their application as excellent adsorbents for metal ions was also demonstrated. The characteristics results of FTIR, SEM, TEM, VSM and XRD showed that MCGO was successfully prepared. The SEM and TEM revealed that magnetic chitosan had been assembled on the surface of graphene oxide layers with a high density. The XRD and VSM indicated the MCGO had enough magnetic response to meet the need of magnetic separation. The magnetic chitosan grafted with graphene oxide sheets showed an increased surface area. The MCGO was used as sorbents for the removal of Pb(II) ions from large volumes of aqueous solutions. The effects of pH, contact time, and concentration on Pb(II) ions sorption were investigated. The results indicated that Pb(II) ions sorption on MCGO was strongly dependent on pH. The abundant functional groups on the surfaces of MCGO played an important role on Pb(II) sorption. Equilibrium studies showed that the data of Pb(II) adsorption followed the Langmuir model. The maximum adsorption capacity for Pb(II) was estimated to be 76.94 mg/g. The MCGO was stable and easily recovered.Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Magnetic chitosan–graphene oxide was successfully synthesized. ► Magnetic chitosan–graphene oxide acted as a novel adsorbent to adsorb Pb(II). ► The adsorption capacity of the biosorbent is higher than other adsorbents. ► It shows the facile and fast separation process of the biosorbent. ► Desorption studies were performed to evaluate adsorbent efficiency.

A chemiluminescence (CL) sensor for the determination of epinephrine using the system of luminol–NaOH–H2O2 based on a graphene oxide–magnetite-molecularly imprinted polymer (GM-MIP) is described. The epinephrine GM-MIP was synthesized using graphene oxide (G) which improved the adsorption capacity, and magnetite nanoparticles which made the polymers easier to use in the sensor. The adsorption performance and properties were characterized. The GM-MIP was used in CL analysis to increase the selectivity and the possible mechanism was also discussed. The CL sensor responded linearly to the concentration of epinephrine over the range 1.04 × 10−7–7.06 × 10−3 mol/L with a detection limit of 1.09 × 10−9 mol/L (3σ). The relative standard deviation for determination was 3.87%. On the basis of speediness and sensitivity, the sensor is reusable and shows a great improvement in selectivity and adsorption capacity over other sensors. The sensor had been used for the determination of epinephrine in drug samples.

A novel flow injection chemiluminescence (FI-CL) sensor for determination of sulfadiazine (SDZ) using core–shell magnetic molecularly imprinted polymers (MMIPs) as recognition element is developed. Briefly, a hydrophilic MMIPs layer was produced at the surface of Fe3O4@SiO2 magnetic nanoparticles (MNPs) via combination of molecular imprinting and reversible stimuli responsive hydrogel. And it provided the MMIPs with excellent adsorption capacity and rapid adsorption rate due to the imprinted sites mostly situated on the surface of MMIPs. Then the prepared SDZ-MMIPs were packed into flow cell to establish a novel FI-CL sensor. The sensor provided a wide linear range for SDZ of 4.0 × 10−7 to 1.0 × 10−4 mol L−1 with a detection limit of 1.54 × 10−7 mol L−1. And the relative standard deviation (RSD) for the determination of 1.0 × 10−6 mol L−1 SDZ was 2.56% (n = 11). The proposed method was applied to determine SDZ in urine samples and satisfactory results were obtained.Graphical abstractThe preparation of core–shell magnetic molecularly imprinted nanoparticles for determination of sulfadiazine in flow injection chemiluminescence.Highlights► A sensitive and selectivity sensor for determination of sulfadiazine was developed. ► The magnetic molecularly imprinted polymers exhibited excellent adsorption property. ► The magnetic imprinted products were introduced as chemiluminescence element. ► The sensor displayed high selectivity, low detection limit and long-term stability etc.

A chemiluminescence (CL) array sensor for determination of benzenediol isomers simultaneously using the system of luminol–NaOH–H2O2 based on a graphene-magnetite-molecularly imprinted polymer (GM-MIP) is described. Use of graphene in the GM-MIP thus prepared is helpful to improve the adsorption capacity, while use of magnetite nanoparticles can facilitate the isolation of GM-MIP at end of their synthesis, and rendering easier the use of the polymers in the array sensor. The adsorption performance and properties were characterized. The GM-MIP was used to increase the selectivity in CL analysis. In addition, the sensor was reusable and of good selectivity and adsorption capacity. The array sensor was finally used for the determination of hydroquinone, resorcinol and catechol in waste water samples simultaneously.Graphical abstractThe sensor realized the separation and determination of benzenediol isomers.Highlights► Determination of benzenediol isomers at the same time. ► A chemiluminescence (CL) array sensor was described. ► Graphene-magnetite-molecularly imprinted polymer was used. ► The adsorption capacity was improved.

A novel flow injection chemiluminescence (FI-CL) sensor for determination of quercetin using the system of luminol-NaOH–H2O2 based on molecularly imprinted polymeric microspheres (MIPm) as recognition element is established. The quercetin MIPm was synthesised by precipitation polymerisation using acetone as solvent, acrylamide (AM) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linker and 2,2-azobisisobutyronitrile (AIBN) as initiator. And the polymers’ properties were characterised. The FI-CL optimised experimental were obtained and the possible mechanism was discussed. The CL intensity responded linearly to the concentration of quercetin ranged from 1.4 × 10−6 to 1.6 × 10−4 mol/L with a detection limit of 9.3 × 10−7 mol/L (3σ). The relative standard deviation (RSD) for determination was ranged from 2.72% to 3.31%. On the basis of speediness and sensitivity, the sensor is reusable and has a great improvement in selectivity. As a result, the new sensor had been successfully applied to the determination of quercetin in drug samples.Highlights► A novel FI-CL sensor based on MIPm as recognition element was established. ► The sensor is reusable and has a great improvement in sensitivity and selectivity. ► In the sensor, measuring samples online was realised by using a two-way switch (T). ► The schematic diagram of the FI-CL sensor and this was the first report.

The adsorption characteristics of hydroquinol from aqueous solutions onto the β-cyclodextrin modified magnetic chitosan nanoparticles (CMCN) had been investigated. The characteristics results of FTIR, SEM and XRD showed that CMCN was successfully prepared. The influences of the pH of the solution and the contact time on the adsorption amounts had been discussed, and the appropriate process conditions for the adsorption of hydroquinol had been obtained. Equilibrium experiments fitted well with the Freundlich isotherm model, and the maximum adsorption capacity of the CMCN at 303 K was determined to be 1.75 mmol/g for hydroquinol at the concentration of 9.0 mmol/L, much higher than some conventional adsorbents. The CMCN was stable and easily recovered. Moreover, the adsorption capacity was about 90% of the initial saturation adsorption capacity after being used four times.Graphical abstractHighlights► Magnetic β-cyclodextrin–chitosan was synthesized as a novel adsorbent to adsorb hydroquinol. ► The adsorption capacity of the magnetic β-cyclodextrin–chitosan is higher than other adsorbents. ► It shows the facile and fast separation process of the magnetic β-cyclodextrin–chitosan.

A novel, chitosan coating on the surface of magnetite (Fe3O4) (MIMC) was successfully synthesized using alizarin red (AR) as a template for adsorption and removal of AR from aqueous solutions. Characterization of the obtained MIMC was achieved by FTIR spectra, SEM micrographs and XRD. Batch adsorption experiments were performed to investigate the adsorption conditions, selectivity and reusability. The results showed that the maximum adsorption capacity was 40.12 mg/g, observed at pH 3 and temperature 30 °C. Equilibrium adsorption was achieved within 50 min. The kinetic data, obtained at the optimum pH 3, could be fitted with a pseudo-second-order equation. Adsorption process could be well described by Langmuir adsorption isotherms and the maximum adsorption capacity was calculated as 43.08 mg/g. The selectivity coefficient of AR and other dyes onto MIMC indicated an overall preference for AR, which was much higher than non-imprinted magnetic chitosan beads. Moreover, the sorbent represented high stability and good repeatability.Graphical abstract.Highlights► The paper is a new method to expand function of the chitosan. ► The method can improve the surface area for adsorption of alizarin red. ► The MIMC can be used effectively and selectively to remove alizarin red from aqueous solutions. ► It shows the facile, fast separation process of magnetic chitosan during the experiments.

This paper reports the preparation of dapsone (DDS) imprinted polymer layer-coated silica submicron particles (SiO2) combined with chemiluminescence (CL) toward analysis of tracing DDS in practical samples. To induce the selective occurrence of surface polymerization, the amino groups were first grafted at the surface of SiO2 by the (3-aminopropyl)triethoxysilane (APTES). The molecularly imprinted polymers (MIP) were coated at the surface of modified SiO2 by the graft copolymerization. After the removal of templates, recognition sites of DDS were exposed in the polymer layers. The DDS-imprinted products were characterized by FT-IR, SEM, TEM, dynamic adsorption, and static adsorption tests. The proximity between the thickness of MIP layer and the spatial size of DDS indicated that the imprinted sites almost situated at the surface of MIP, leading to rapid adsorption saturation within 90 min. The apparent maximum binding amount of MIP toward DDS was evaluated as 14.98 mg·g−1, which was much higher than that of non-molecularly imprinted polymers. The CL sensor provided a wide linear range for DDS within 1.0 × 10−6 to 1.0 × 10−4 mol·L−1 with a detection limit of 5.27 × 10-7 mol·L−1 and the relative standard deviation of 1.8 % (n = 11) by determinations of 5.0 × 10−6 mol·L−1 DDS. This method was applied to determine DDS in urine samples and satisfactory results were obtained.

A new method for determination of l-tryptophan (l-try) using the flow injection chemiluminescence (FI-CL) system of KMnO4–SnCl2–CHOH based on a graphene oxide–magnetite-molecularly imprinted polymer (GM-MIP) is described. The l-try GM-MIP was synthesized using graphene oxide (G) which improved the adsorption capacity as carrier, and magnetite nanoparticles which made the polymers easier to use in the sensor. The adsorption performance and properties were characterized. The GM-MIP was used in CL analysis to increase the selectivity and the possible mechanism was also discussed. The CL sensor responded linearly to the concentration of l-try over the range from 2.10×10−7 to 7.09×10−4 M with a detection limit of 2.11×10−8 M (3σ). The relative standard deviation (RSD) for the determination of 3.0×10−5 M l-try was 2.40% (n=11). On the basis of speediness and sensitivity, the sensor is reusable and shows a great improvement in selectivity and adsorption capacity over other sensors. The sensor has been used for the determination of l-try in drug samples.Highlights► Graphene oxide was used for improving the adsorption capacity. ► Fe3O4 nanoparticles were used for separation and immobilization. ► The sensor is reusable with great improvement in sensitivity and selectivity.

A novel molecular imprinting-chemiluminescence (MIP-CL) sensor for the determination of l-phenylalanine (Phe) using molecularly imprinted polymer (MIP) as recognition element is reported. The Phe-MIP was synthesized using acrylamide (AM) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker, 2,2-azobisisobutyronitrile (AIBN) as initiator and the polymers’ properties were characterized. Then the synthesized MIP was employed as recognition element by packing into flow cell to establish a novel flow injection CL sensor. The CL intensity responded linearly to the concentration of Phe in the range 1.3 × 10−6 to 5.44 × 10−4 mol/L with a detection limit of 6.23 × 10−7 mol/L (3σ), which is lower than that of conventional methods. The sensor is reusable and has a great improvement in sensitivity and selectivity for CL analysis. As a result, the new MIP-CL sensor had been successfully applied to the determination of Phe in samples.Graphical abstractHighlights► The recognition-cell of sensor was placed in front of CL analyzer. ► A switch was used which makes the operation simple in recognition part. ► A straight shape tube filled with MIP for full reaction was used.

The host–guest complexation between p-sulfoniccalix[8]arene (SC8A) and norfloxacin (NFLX) in aqueous solution was investigated by fluorescence spectroscopy. Strong fluorescence intensity of the NFLX aqueous solution alone and obvious fluorescence quenching of NFLX solution in the presence of SC8A were observed. The fluorescence lifetimes of NFLX and SC8A–NFLX inclusion complex were determined and the effect of temperature on SC8A–NFLX inclusion complex was studied. The static quenching of the inclusion was obtained, that is the SC8A can form a nonfluorescent ground-state inclusion complex with NFLX. As the results show, the combined ratio (n) was 1:1 and association constant K was 1.17×105 L/mol. Based on the experimental results, the mechanism of the inclusion complex was explored. The space matching, electrostatic force and hydrogen bond play important effects in the inclusion process. Subsequently, the addition of bovine serum albumin (BSA) solution led to the recovery of fluorescence intensity. It is indicated that BSA can liberate the NFLX into the solution by destructing the SC8A–NFLX inclusion complex. Hence SC8A may be used for controlled-release drug delivery in the pharmaceutical industry.Highlights► Fluorescence lifetimes of NFLX and SC8A–NFLX inclusion complex were determined. ► Mechanism of the SC8A–NFLX inclusion complex was explored. ► It is proved that SC8A can form a nonfluorescent ground-state inclusion complex with NFLX.

A novel chemiluminescence (CL) sensor for the on-site determination of vanillin using the system of luminol–KMnO4–NaOH based on a magnetic graphene oxide molecularly imprinted polymer (GM-MIP) is described. The vanillin–GM-MIP system, which has the merits of easy separation, high selectivity and a large amount of adsorption, was synthesized as a vanillin recognition material in the CL analysis, where the GM-MIP column was placed ahead of the pump in the experimental setup so as to increase the selectivity of CL analysis. The GM-MIP was characterized by SEM, XRD, TEM and FTIR, and also for its adsorption ability, selectivity and reusability. The GM-MIP-CL sensor responded linearly to the concentration of vanillin over the range 3.3 × 10−7 to 1.2 × 10−5 mol L−1 with a detection limit of 1.1 × 10−7 mol L−1 (3δ). The RSD was 3.9%, and on the basis of speediness and high selectivity the sensor showed a great improvement in selectivity and adsorption capacity. Finally, the sensor was applied to the determination of vanillin in practical samples, and the recoveries were between 6% and 8%. The sensor was an easily producible, simple automatic column packing with high selectivity.