Search

In spite of the high-brightness of perovskite quantum dots (QDs), their instability and sensitive to oxygen and moisture are still major challenges that obstruct their analytical applications. This work demonstrates the fabrication and application of perovskite CsPbBr3 QDs embedded in a molecularly imprinted polymer (MIP) for specific and sensitive detection of phoxim in real samples. CsPbBr3 QDs were obtained via a simple and convenient hot injection method. Based on the chemical structure of phoxim, we designed and synthesized a siloxane functional monomer with multiple functional groups to allow various types of interactions with phoxim. Next, the MIP/QDs composites were synthesized by slowly hydrolyzing the organosilicon monomers in situ. The obtained MIP/QDs composites possessed excellent selectivity for phoxim, and the imprinting factor of the optimized MIP/QDs was 3.27. Compared with previous studies regarding the detection of organophosphorus pesticides, the MIP/QDs fluorescence sensor exhibited high sensitivity and specificity. Under optimal conditions, the fluorescence quenching of the MIP/QDs had a good linear correlation for phoxim in the concentration range of 5–100 ng/mL, and with a limit of detection of 1.45 ng/mL. Finally, the method was used for the detection of phoxim in potato and soil samples, achieving recoveries of 86.8–98.2%.

This paper describes an alternative strategy for the preparation of highly ordered molecularly imprinted mesoporous silica microspheres (MIMSM) for the selective fluorescence sensing of sparfloxacin in biological samples. We designed and synthesized a new functional monomer through the thiol-ene click chemistry reaction of 3-(methacryloyloxy) propyltrimethoxysilane and 3-mercaptopropionic acid. Sparfloxacin was selected as a template, and Mn-doped ZnS quantum dots served as the signal transducing element. This one-pot strategy was used to fabricate the MIMSM. Fourier transform infrared spectroscopy demonstrated successful embedding of a functional monomer in the mesoporous silica microspheres, and the highly ordered, periodic hexagonal mesoporous structure of MIMSM was confirmed with small angle X-ray diffraction, transmission electron microscopy, and N2 adsorption-desorption measurements. The fluorescence intensity of the MIMSM had linear correlation with 0.05–2.0 μg/mL sparfloxacin. There was a rapid response time and excellent selectivity for structural analogues. Under optimal conditions, the limit of detection was 0.012 μg/mL for sparfloxacin. This method was then used with serum samples to achieve recoveries of 88.8–102%.

This paper describes an alternative strategy for fabricating a fluorescent aptamer functionalized molecularly imprinted polymer (MIP) for highly specific sensing of kanamycin. The technique provides surface imprinting in aqueous solutions using CdSe quantum dots as supports, thiols modified aptamer and methacrylic acid as functional monomers, and kanamycin as a template. The MIP would function utilizing double recognition of the aptamer and imprinted cavities for fluorescent sensing of kanamycin. The “thiol-ene” click reaction was utilized to fix the aptamer into polymer matrix, and the click chemistry used was highly efficient under mild condition and environmentally friendly. Experimental results indicated that there was a synergistic interaction between the aptamer and MAA, which improved the recognition ability of MIP toward kanamycin. The MIP showed an imprinting factor of 3.51 for kanamycin, excellent analog selectivity, and strong resistance toward ions interference. The fluorescence intensity of the MIP enhanced gradually with increase in the concentration of kanamycin, and exhibited good linear correlation within the concentration of 0.05–10.0 μg/mL with a detection limit of 0.013 μg/mL. This fluorescent MIP was further applied to quickly, sensitively and simply sensing of kanamycin in food, water and biological samples which yielded satisfied results.

We developed two types of novel highly ordered Ni 2+ imprinted mesoporous organosilica materials (SBA-15 (NiIMS1) and MCM-41 (NiIMS2)) through co-condensation for selective adsorption of Ni 2+ from electroplating Ni 2+ effluents. FTIR and solid-state 13 C NMR spectra demonstrated the successful embedment of functionalized iminodiacetic acid and ethanediamine chelating groups in NiIMS1 and NiIMS2, respectively. X-ray photoelectron spectroscopy analysis confirmed that Ni 2+ was coordinated by N atom and carboxyl O atom of the functional groups. Furthermore, NiIMS1 and NiIMS2 displayed highly ordered periodic hexagonal P6mm meso-structure, large surface area, and highly specific recognition ability toward Ni 2+ . The adsorption experimental results proved that NiIMS1 was suitable for acidic wastewater treatment, whereas NiIMS2 was fit for alkaline wastewater. The saturated adsorption capacity of NiIMS2 was 20.8 mg/g at pH 6.0, and that of NiIMS1 reached up to 22.9 mg/g at pH 3.0. The values of selectivity coefficients of NiIMS1 and NiIMS2 for five competing metal ions ranged from 46.4 to 12.4 and 36.9 to 18.8, respectively. The adsorption efficiency of NiIMS1 was above 92.5% even after seven extraction-stripping cycles, while that for NiIMS2 was 90.9%. The real sample adsorption experiments demonstrated that these mesoporous organosilica materials have high potential for water treatment applications.

This paper demonstrates the development and validation of a high-performance liquid chromatography (HPLC) method for the determination of pyrimethamine in fish and plasma samples using core–shell molecularly imprinted polymers (MIPs). The MIPs were synthesized based on thiol–ene click chemistry, using pentaerythritol tetra (3-mercaptopropionate) and dipentaerythritol pentaacrylate as binary cross-linkers, pyrimethamine as a template and methacrylic acid as a functional monomer. The MIPs were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The MIPs were used as matrix solid-phase dispersion extraction sorbents for the separation of pyrimethamine in fish and plasma samples. The results show that the developed MIPs had higher extraction capacity toward pyrimethamine than non-imprinted polymers (NIPs), high selectivity among pyrimethamine analogues, and a saturation capacity of 41.9 μmol g−1. Furthermore, the proposed method was validated for linearity, precision, accuracy, and it has been applied for the analysis of pyrimethamine in fish and plasma samples, obtaining satisfactory recoveries.

This work demonstrates a simple strategy for producing highly selective adsorption magnetic ion imprinted mesoporous silica (MIIMS) nanocomposites. They have been functionalized by a γ-(aminoethylamino)propyl chelating group for specific recognition and rapid removal of toxic heavy metal ions from wastewaters. The superparamagnetic Fe3O4 nanocrystal was encapsulated in an imprinted mesoporous organosilica shell via a co-condensation synthesis method. The results of transmission electron microscopy (TEM) and small angle X-ray diffraction (XRD) confirmed that the imprinted mesoporous organosilica shell preserved a highly ordered 2D mesostructure. The Brunauer–Emmett–Teller (BET) analysis found the surface area was 946 m2 g−1. The saturated adsorption capacity of MIIMS toward cadmium reached up to 25.2 mg g−1 (0.224 mmol g−1) at pH 5.0. The adsorption of cadmium reached an equilibrium within 4.5 min. The results of a selectivity study revealed that the adsorption capacity for Cd2+ is much high than other co-existing heavy metal ions. The adsorption efficiency of MIIMS was above 94.2% after six extraction-stripping cycles. The MIIMS can efficiently remove cadmium ions in water treatment applications.

We developed an effective and selective method to remove Cr(III) ions in acidic effluents. This method used combined ion imprinted technology with mesoporous silica materials. Cr(III) ion imprinted mesoporous silica (CrIMS) was synthesized and used as an excellent adsorbent. Iminodiacetic acid (IDA) was silanized, and acted as a functional monomer. The chemical groups, thermal stability, porosity and highly ordered morphology of CrIMS were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) isotherms, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The Brunauer–Emmett–Teller (BET) surface area was 856.24 m2 g−1. The saturated adsorption capacity of CrIMS towards Cr(III) ions reached up to 63 mg g−1 at pH 4.5. At a concentration of 200 mg L−1, the adsorption of Cr(III) ions reached equilibrium within 5 min and 20 min at pH 4.5 and pH 3.0, respectively. The CrIMS showed highly specific adsorption capacity and the imprinting factor was up to 4.03 at pH 3.0. The adsorption capacity of Cr(III) ions was remarkably higher than other co-existing metal ions. After eight adsorption–regeneration cycles, the adsorption efficiency of CrIMS still reached above 94.1%. The CrIMS could effectively remove Cr(III) ions below the discharge standard of China in real sample treatment.

The preparation of molecularly imprinted mesoporous silica with perovskite quantum dots (QDs) grown in situ and their applications for highly sensitive fluorescence sensing of 2,2-dichlorovinyl dimethyl phosphate (DDVP) is presented. Highly ordered mesoporous silica materials were synthesized and employed as solid supports. Uniform and highly luminescent CsPbBr3 QDs were grown in the pores of these mesoporous silica. Subsequently, surface graft imprinting was applied on the surface of the QDs-encapsulated mesoporous silica. The QDs were acted as a recognition signal transducer and the molecular imprinting process provided recognition sites for 2,2-dichlorovinyl dimethyl phosphate. The QDs grown in situ in SBA-15 mesopores greatly improved the sensitivity for the determination of 2,2-dichlorovinyl dimethyl phosphate. Under the optimized conditions, the QDs-encapsulated molecularly imprinted mesoporous silica was linear between the concentration of 5 and 25 μg/L for DDVP, and detection limit was 1.27 μg/L. The QDs-encapsulated molecularly imprinted mesoporous silica was subsequently applied to the fluorescence analysis of 2,2-dichlorovinyl dimethyl phosphate in cabbage and lettuce samples and achieved recoveries from 87.4% to 101%. The time-resolved photoluminescence decay and UV–vis spectroscopic studies indicated that the quenching mechanism on the fluorescence of the QDs can be attributed to charge transfer between the QDs and DDVP.

In the current study, a new strategy for the extraction of bisphenol A (BPA) from milk has been employed by using surface-imprinted core-shell magnetic beads, prepared by the reversible addition-fragmentation chain transfer (RAFT) polymerization. In order to obtain highly selective recognition cavities, an enhanced imprinting method based on binary functional monomers, e.g. 4-vinylpyridine (4-VP) and β-cyclodextrin (β-CD), was chosen for BPA imprinting. The morphological and magnetic properties of the Fe3O4-MIP beads were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FT-IR) Spectroscopy, Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM). The characterization results suggested that MIP was synthesized evenly on Fe3O4-SiO2 surface. The adsorption experiments revealed that Fe3O4-MIPs showed better extraction capacity and selectivity toward BPA and its analogues than the non-imprinted polymers (NIPs). The saturation capacity of Fe3O4-MIP was 17.98 mg/g. In milk samples, the present method displayed a lower the detection thresholds, down to 3.7 μg/L. The recoveries of BPA in milk samples for three concentrations were found to be within 99.21%, 98.07% and 97.23%, respectively to three concentrations: 1.0 μmol/L, 10.0 mol/L, 100.0 μmol/L. Thus, the MIPs can be used for remove BPA in milk samples.

This article describes a method for determination of four aflatoxins by a combination of ultra-high performance liquid chromatography and mass spectrometry (UHPLC-MS/MS). Magnetic dummy molecularly imprinted polymers (md-MIPs) are used for fairly selective preconcentration. The preparation of the md-MIP involves (a) coating of magnetic nanoparticles (with a typical diameter of 200 nm) with a shell of silica, (b) modifying the surface with methacryloxy groups, and (c) creating a MIP on the surface by graft imprinting in aqueous solutions using 5,7-dimethoxycoumarin as the dummy template, and methacrylic acid and 4-vinylpyridine as the functional monomers. After elution of the template, the md-MIPs can be used for fairly selective extraction of the aflatoxins B1, B2, G1 and G2. Following magnetic separation of the particles, the aflatoxins were eluted and quantified by UHPLC-MS/MS. The limit of detection is 0.05 μg·kg−1 for aflatoxins B2 and G2, and 0.1 μg·kg−1 for aflatoxins B1 and G1. False-positive samples were identified by UHPLC-MS/MS in the positive ionization mode with multiple reaction monitoring.

All-inorganic cesium lead halide perovskites (CsPbX3, X = Cl, Br, and I) have attracted considerable attention with superior electrical and photophysical properties. In this study, luminescent perovskite (CsPbBr3) quantum dots (QDs) as sensing elements combined with molecularly imprinted polymers (MIPs) are used for the detection of omethoate (OMT). The new MIPs@CsPbBr3 QDs were synthesized successfully through the imprinting technology with a sol–gel reaction. The fluorescence (FL) of the MIPs@CsPbBr3 QDs was quenched obviously on loading the MIPs with OMT, the linear range of OMT was from 50 to 400 ng/mL, and the detection limit was 18.8 ng/mL. The imprinting factor was 3.2, which indicated excellent specificity of the MIPs for the inorganic metal halide (IMH) perovskites. The novel composite possesses the outstanding FL capability of CsPbBr3 QDs and the high selectivity of molecular imprinting technology, which can convert the specific interactions between template and the imprinted cavities to apparen...

In order to develop a highly efficient method for direct removal of lead from acidic wastewater (pH 2.0), we introduce a novel highly ordered Pb2+ imprinted mesoporous silica (PbIMS) SBA-15 combining co-condensation and functionalized iminodiacetic acid (IDA). Fourier transform infrared spectroscopy (FTIR) and energy-dispersive X-ray (EDX) analysis provided the components of PbIMS. The solid-state 13C NMR spectra demonstrated the successful embedment of IDA in the mesoporous silica. Furthermore, X-ray photoelectron spectroscopy (XPS) analysis confirmed that Pb2+ was coordinated by the N atom and carboxyl O atom of IDA. The results of transmission electron microscopy (TEM), small angle X-ray diffraction (XRD) and N2 adsorption–desorption measurement confirmed that the PbIMS preserved a highly ordered hexagonal P6mm mesostructure. The Brunauer–Emmett–Teller (BET) surface area was 762 m2 g−1. The saturated adsorption capacity of PbIMS toward lead reached up to 103 mg g−1 at pH 2.0, which was greater even than that of the simply modified SBA-15 by IDA at pH 4.5. The values of selectivity coefficients of PbIMS for six competing metal ions ranged from 67.3 to 12.7. The adsorption of Pb2+ reached equilibrium within 7 min. The adsorption efficiency of PbIMS was above 93% after six extraction–stripping cycles. The investigation conducted with real samples of strongly acidic wastewater demonstrated the ability of PbIMS to efficiently remove lead below the current China regulatory standard.

This paper demonstrates a new strategy for developing a fluorescent glycosyl-imprinted polymer for pH and temperature regulated sensing of target glycopeptide antibiotic. The technique provides amino modified Mn-doped ZnS QDs as fluorescent supports, 4-vinylphenylbronic acid as a covalent monomer, N-isopropyl acrylamide as a thermo-responsive monomer in combination with acrylamide as a non-covalent monomer, and glycosyl moiety of a glycopeptide antibiotic as a template to produce fluorescent molecularly imprinted polymer (FMIP) in aqueous solution. The FMIP can alter its functional moieties and structure with pH and temperature stimulation. This allows recognition of target molecules through control of pH and temperature. The fluorescence intensity of the FMIP was enhanced gradually as the concentration of telavancin increased, and showed selective recognition toward the target glycopeptide antibiotic preferentially among other antibiotics. Using the FMIP as a sensing material, good linear correlations were obtained over the concentration range of 3.0-300.0μg/L and with a low limit of detection of 1.0μg/L. The analysis results of telavancin in real samples were consistent with that obtained by liquid chromatography tandem mass spectrometry.

Applying molecular imprinting techniques to the surface of functionalized quantum dots (QDs) allows the preparation of molecularly imprinted polymers (MIPs) with accessible, surface exposed binding sites and excellent optical properties. This paper demonstrates a new strategy for producing such hybrid organic–inorganic imprinted Mn-doped ZnS QDs for specific recognition of bovine hemoglobin. The technique provides surface grafting imprinting in aqueous solutions using amino modified Mn-doped ZnS QDs as supports, acrylamide and methacrylic acid as functional monomers, γ-methacryloxypropyl trimethoxy silane as the grafting agent, and bovine hemoglobin as a template. The amino propyl functional monomer layer directs the selective occurrence of imprinting polymerization at the QDs surface through copolymerization of grafting agents with functional monomers, but also acts as an assistive monomer to drive the template into the formed polymer shells to create effective recognition sites. Using MIP-QDs composites as a fluorescence sensing material, trace amounts of bovine hemoglobin are signaled with high selectivity by emission intensity changes of Mn-doped ZnS QDs, which is embedded into the imprinted polymers.

Applying molecular imprinting techniques to the surface of functionalized SiO2 allows the preparation of molecularly imprinted polymers (MIPs) with accessible, high affinity and surface exposed binding sites. This paper demonstrates a new strategy for producing such hybrid organic-inorganic surface imprinted silica nanoparticles for specific recognition of methyl parathion. The technique provides surface grafting imprinting in chloroform using amino modified silica nanoparticles as supports, acrylamide as the functional monomer, γ-methacryloxypropyl trimethoxy silane as the grafting agent, and methyl parathion as a template. The amino propyl functional monomer layer directs the selective occurrence of imprinting polymerization at the silica surface through copolymerization of grafting agents with functional monomers, but also acts as an assistive monomer to drive the template into the formed polymer shells to create effective recognition sites. The resulting MIPs-SiO2 nanoparticles display three-dimensional core-shell architectures and large surface areas. The molecularly imprinted shell provides recognition sites for methyl parathion, with the materials exhibiting excellent performance for selecting the template. Using MIPs-SiO2 nanoparticles as a matrix of solid-phase dispersion extraction sorbents, trace amounts of methyl parathion are selectivity extracted from pear and green vegetable samples while simultaneously eliminating matrix interferences, attaining recoveries of 84.7-94.4% for the samples.

Restricted rotation of the ortho sulfinyl groups directs the trans ortho-substituted bis-sulfoxide (3) to adopt right-handed (P) or left-handed (M) conformation and thus produces symmetric atropisomeric (R,R)-3/(S,S)-3 and asymmetric atropisomeric enantiomers (R,S)-3, respectively. (R,S)-3 exhibits spontaneous resolution and crystallizes as a conglomerate (P,R,S)-3/(M,R,S)-3 with a homochiral supramolecular helix (P/M-helix) conformation.

This paper demonstrates a novel approach to assembling homogeneous molecularly imprinted polymers (MIPs) based on mimicking multiple hydrogen bonds between nucleotide bases by preparing acyclovir (ACV) as a template and using coatings grafted on silica supports. (1)H NMR studies confirmed the AAD-DDA (A for acceptor, D for donor) hydrogen-bond array between template and functional monomer, while the resultant monodisperse molecularly imprinted microspheres (MIMs) were evaluated using a binding experiment, high performance liquid chromatography (HPLC), and solid phase extraction. The Langmuir isothermal model and the Langmuir-Freundlich isothermal model suggest that ACV-MIMs have more homogeneous binding sites than MIPs prepared through normal imprinting. In contrast to previous MIP-HPLC columns, there were no apparent tailings for the ACV peaks, and ACV-MIMs had excellent specific binding properties with a Ka peak of 3.44 × 10(5)M(-1). A complete baseline separation is obtained for ACV and structurally similar compounds. This work also successfully used MIMs as a specific sorbent for capturing ACV from serum samples. The detection limit and mean recovery of ACV was 1.8 ng/mL(-1) and 95.6%, respectively, for molecularly imprinted solid phase extraction coupled with HPLC. To our knowledge, this was the first example of MIPs using AAD-DDA hydrogen bonds.

A hydroquinidine-imprinted stationary selector with chiral recognition for cinchona alkaloids was prepared by bulk polymerization with (+)-(2R,3R)-N,N′-diallyl-L-tartardiamide as a functional monomer, and the recognition properties of the polymers for quinidine (QD) were analyzed with high-performance liquid chromatography. By optimizing the preparation conditions and chromatographic conditions, such as the ratio of the mobile phase and flow rate, QD and quinine could be completely separated to the best resolution of 2.25. The chiral molecularly imprinted polymers (CMIPs) combined the virtues of traditional brush-type chiral selectors with existing CMIPs. The results show a substantial synergistic effect between the chiral monomer and the chiral cavity of the resulting CMIPs in chiral recognition. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

α-Amanitin and β–amanitin are the main toxins of mushroom poisoning. The application of traditional non-selective adsorbents is not satisfactory in clinical treatment of amanita mushroom poisoning due to lack of specificity adsorption capability of these adsorbents toward amanitin toxins. In the current work, we introduce a novel molecularly imprinted biomimetic adsorbent based on a ligand specificity determinant through surface imprinted strategy. Owing to the expensive price of the amanitin sources, we selected a typical common moiety of α, β–amanitin as specificity determinant to synthesize a template necessary for the preparation of molecularly imprinted polymers (MIPs). Computer simulation was used to initially select acidic methacrylic acid (MAA) and basic 4-vinyl pyridine (4-VP) together as functional monomers. The experiments further demonstrated that the synergistic interaction of MAA and 4-VP played a primary role in the recognition of α, β-amanitin by MIPs. By means of batch and packed-bed column experiment and the hemocompatibility evaluation, the resultant biomimetic adsorbent has been proved to be capable of selectively removing α, β–amanitin and possess good hemocompatibility. This novel adsorbent has great potential to find application in human plasma purification.

To extract aconitine from body fluid samples, aconitine-molecularly imprinted polymer microspheres with the optimum molar ratios of template/monomer/cross-linker (1:8:40) as selective sorbents were synthesized by precipitation polymerization. Excellent retention of aconitine on the molecularly imprinted microspheres (MIMs) cartridge was achieved by optimizing the MISPE process, and the binding capacity reached 0.802mg/g, yielding an imprinting factor of 4.76. The MIMs also showed high selectivity for aconitum alkaloids, but not for other kinds of poisonous alkaloids. High recoveries (>89%) for aconitine, hypaconitine, and mesaconitine were got in spiked serum samples. The working curves show linear dependence on aconitine concentration in the range of 2.0–0.1 µg/mL, and the detection limits of aconitine, hypaconitine, and mesaconitine were 16.7, 18.3, 10.2 ng mL–1, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Using a combination of molecular imprinting technology and traditional chiral stationary phases, the synergistic effect between chiral monomer and chiral cavity of molecularly imprinted polymers in stereoselective recognition was investigated. We designed and synthesized an amino acid derivative to be used as a novel chiral functional monomer. Monodisperse molecularly imprinted core-shell microspheres using surface imprinting method on silica gel were prepared with hydroquinidine as the pseudo-template molecule for the resolution of cinchona alkaloids. The results showed a significant synergistic effect in stereoselective recognition, confirming our initial hypothesis. Furthermore, our computational simulation and experiments intensively support the hypothetical chiral recognition mechanism for the imprinted microspheres.

Similar to those in complementary nucleotides' base pairs, we present a novel molecularly imprinted electrochemical sensor for emodin, constructed using a multiple hydrogen bonds strategy. We obtained the sensor by in situ photopolymerization, using allobarbital as a new functional monomer. We optimized the conditions of membrane imprinting and the composition of adsorption solvent. This artificial receptor exhibits high selectivity for the template in comparison with closely related analogs, aloin A and simetryne. The sensor was successfully applied in determination of emodin levels in one of the traditional Chinese medicines, the content of emodin in Sanhuang tablets detected using the voltammetric sensor and high performance liquid chromatography (HPLC) were 0.249 ± 0.009 (mg/tablet) and 0.246 ± 0.007 (mg/tablet), respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A novel molecular imprinted solid-phase extraction technique was developed by using microspheres prepared by modifying the silica through a sol-gel process with a layer of homogeneous and compact molecularly imprinted polymer (MIP), which was synthesized with 3-aminopropyltriethoxysilane and phenyltrimethoxysilane as functional monomers, diethylstilbestrol (DES) as the template, and tetraethoxysilane as the cross-linker. The saturated adsorption capacity of the MIP under the condition of continuous loading of target solution was 0.213 mg g−1, and the imprinting factor reached 6.0. The selectivity factor of the MIPs for bisphenol A and 4-tert-butylphenol were 3.5 and 9.6, respectively. The molecular imprinted solid-phase extraction (MISPE) is a viable and efficient technique for extraction of DES from chicken samples with a recovery ofmore than 85%. The limit of detection (LOD) was determined to be 8 ng g−1.

A triazolam-imprinted silica microsphere was prepared by combining a surface molecular-imprinting technique with the sol–gel process. The results illustrate that the triazolam-imprinted silica microspheres provided using γ-aminopropyltriethoxysilane and phenyltrimethoxysilane as monomers exhibited higher selectivity than those provided from γ-aminopropyltriethoxysilane and methyltriethoxysilane. In addition, the optimum affinity occurred when the molar ratio of γ-aminopropyltriethoxysilane, phenyltrimethoxysilane, and the template molecule was 4.2:4.7:0.6. Retention factor (k) and imprinting factor (IF) of triazolam on the imprinted and non-imprinted silica microsphere columns were characterized using high performance liquid chromatography (HPLC) with different mobile phases including methanol, acetonitrile, and water solutions. The molecular selectivity of the imprinted silica microspheres was also evaluated for triazolam and its analogue compounds in various mobile phases. The better results indicated that k and IF of triazolam on the imprinted silica microsphere column were 2.1 and 35, respectively, when using methanol/water (1/1, v/v) as the mobile phase. Finally, the imprinted silica was applied as a sorbent in solid-phase extraction (SPE), to selectively extract triazolam and its metabolite, α-hydroxytriazolam, from human urine samples. The limits of detection (LOD) for triazolam and α-hydroxytriazolam in urine samples were 30 ± 0.21 ng mL−1 and 33 ± 0.26 ng mL−1, respectively.

The homogeneous molecularly imprinted microspheres (MIMs) based on a biologically inspired hydrogen-bond array were prepared using allobarbital as the novel functional monomer and divinylbenzene as the cross-linker. The host-guest binding characteristics were examined by molecular simulation and infrared spectroscopy. The resultant MIMs were evaluated using high performance liquid chromatography and solid-phase extraction. The results obtained demonstrate that the good imprinting effect and the excellent selectivity of MIMs are mainly due to the interaction involving the formation of three-point hydrogen bond between host and guest. The complete baseline separation was obtained for five triazine analogues and a metabolite on the MIM HPLC column. The MIMs were further successfully used as a specific sorbent for selective extraction of simetryne from corn and soil samples by molecularly imprinted solid phase extraction. Detection limits and recoveries were 5.8 μg/kg and 0.14 μg/kg and 87.4-105% and 94.6-101% for simetryne in corn and soil sample, respectively.

A novel estazolam-imprinted silica sorbent was prepared by the surface imprinting technique using 3-aminopropyltriethoxysilane (APTEOS) and phenyltrimethoxysilane (PTMOS) as functional monomers. The functional monomers are expected to form hydrogen bonds and π-π interactions with estazolam. The imprinted silica sorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), element analysis, and scanning electron micrograph (SEM). Compared to C18 solid phase extraction (SPE) and liquid-liquid extraction, molecular imprinting polymer (MIP) SPE was the most feasible method to extract estazolam from human plasma, and the recovery of estazolam was up to 98.7±1.2%.

A nicotinic acid sensor based on molecular imprinting technology was fabricated by in situ photopolymerization. After the template was extracted, incubation and measurements were carried out directly. The response of the sensor was linear, with nicotinic acid concentrations in the range of 0.05–5mmol/L. Due to the imprinting effect, the sensor exhibited high selectivity for the template compared to closely related analogs such as benzoic acid and isonicotinic acid. Scanning electron microscope images showed no obvious difference between the imprinted electrode surface and the non‐imprinted one. This sensor was also used to determine nicotinamide in a Wahaha soft drink sample.

The major challenges in measuring plasma renin activity (PRA) stem from the complexity of biological matrix, as well as from the instability and low circulating concentration of angiotensin. In this study, an ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) based technique has been developed for the measurement of angiotensin using magnetically imprinted polymers for simultaneous enrichment of the precursor peptide angiotensin II (Ang II) and the upstream peptide precursor angiotensin I (Ang I). This technique involved surface graft imprinting in aqueous solutions using vinyl-modified nano-iron oxide as solid supports, the specificity determinant of Ang I and Ang II as the epitope, and methacrylic acid and N-t-butylacrylamide as functional monomers. The vinyl-modified nano-iron oxide acted as a magnetic separation media, and the molecularly imprinted shell provided analyte selectivity for the recognition of Ang I and Ang II. Selective enrichment of Ang I and Ang II was accomplished by the magnetically imprinted polymers, followed by a magnetic separation procedure and subsequent quantification by UPLC-MS/MS in the positive ionization mode with multiple reaction monitoring. Through the latter protocol, a low limit of detection could be realized, viz. 0.07ng/mL and 0.06ng/mL for Ang I and II, respectively, which was thoroughly validated for accuracy and reproducibility through analyzing Ang I and Ang II in human plasma samples.

α-amanitin could make patients die of acute liver failure within a short time if suitable treatment is not provided in a timely fashion. This paper demonstrates a new strategy for direct detection of α-amanitin in serum using carbon quantum dots-embedded specificity determinant imprinted polymers. According to the structure of α-amanitin, we selected a proper moiety of α-amanitin as specificity determinant to synthesize template to prepare the MIPs. The computer simulation was used to screen out acidic methacrylic acid (MAA) and basic 4-vinyl pyridine (4-Vpy) together as functional monomers, and the experiments further proved that synergistic interaction of MAA and 4-Vpy was beneficial to enhance the recognition capability of MIPs for α-amanitin. Moreover, the fluorescence intensity showed good linear correlations with the concentration of α-amanitin from 0.05 to 4.0μgmL(-1). The detection limit for α-amanitin was 15ngmL(-1). The nanoparticles were employed to directly detect α-amanitin in serum without any pretreatment with recoveries of 97.8-100.9%.

Polymers imprinted with cefathiamidine were synthesized using 4‐vinylpyridine as an interacting monomer, ethyleneglycol dimethacrylate as a cross‐linker, and methanol and toluene as a porogen. The polymer was used as solid‐phase extraction sorbent. One‐hundred percent of the cefathiamidine was bound to the polymer and the target can be eluted efficiently only by 1 ml eluant. Human plasma and serum samples were preconcentrated by the molecularly imprinted solid‐phase extraction prior to analysis by HPLC. Recoveries of up to 98% were achieved. The molecularly imprinted solid phase extraction column can be used repeatedly. The Guangdong Natural Science Foundation (No. 31503) and Baiyunshan Chemical Pharmaceutical Factory in Guangzhou are gratefully acknowledged.

Core-shell magnetic methyl parathion (MP) imprinted polymers (Fe3O4@MPIPs) were fabricated by a layer-by-layer self-assembly process. In order to take full advantage of the synergistic effect of hydrogen-binding interactions and π-π accumulation between host and guest for molecular recognition, methacrylic acid and 4-vinyl pyridine were chosen as co-functional monomers and their optimal proportion were investigated. The core-shell and crystalline structure, morphology and magnetic properties of Fe3O4@MPIPs were characterized. The MP-imprinted nanoshell was almost uniform and about 100nm thick. Binding experiments demonstrated that Fe3O4@MPIPs possessed excellent binding properties, including high adsorption capacity and specific recognition, as well as fast adsorption kinetics and a fast phase separation rate. The equilibration adsorption capacity reached up to 9.1mg/g, which was 12 times higher than that of magnetic non-imprinted polymers, while adsorption reached equilibrium within 5min at a concentration of 0.2mmol/L. Furthermore, Fe3O4@MPIPs successfully provided selective separation and removal of MP in soils with a recovery and detection limit of 81.1-87.0% and 5.2ng/g, respectively.

Mercury pollution is one of the most serious concerns to human health and the environment. The development of highly sensitive and selective sensors to detect toxic mercury ions has been the focus of scientific research. In this study, L-cysteine-capped Mn-doped ZnS quantum dots (QDs) have been synthesized and used for the room temperature phosphorescence detection of Hg2+. The phosphorescence of the Mn-doped ZnS QDs could be selectively quenched in the presence of Hg2+. Under optimal conditions, good linear correlations were obtained over the concentration range from 2.0 x 10(-8) mol/L to 4.5 x 10(-6) mol/L with a detection limit of 3.8 x 10(-9) mol/L. Additionally, the long lifetime of the phosphorescence of the Mn-doped ZnS QDs can avoid the interference of the autofluorescence and scattering light of the background, which facilitates their application in real samples. The possible quenching mechanism was examined by UV-vis absorption spectra and Rayleigh scattering spectra.

A biological organism (chitosan) was utilized to preconcentrate lead ions from tap water. This preconcentration was achieved by mixing 0.8 ml of chitosan slurry with 10-50 ml of lead-containing solution and subsequently separating by centrifugation. The chitosan paste was then dissolved in 1 ml of 0.2% nitric acid and analysed by graphite furnace atomic absorption spectrometry. The extraction efficiency can approach 100% in the pH range 4-10. The amount of chitosan used was not critical. The effect of some impurities was also investigated. If six samples were prepared simultaneously, the time needed to preconcentrate each sample was less than 3 min. Two different modes of standard addition (the standard lead solutions being added before and after preconcentration) were used for analysis of tap water samples, and the results obtained by the two modes were found to be quite consistent.

The direct correlation between disease states and protein levels makes the sensitive, convenient, and precise detection of proteins the focus of scientific research. This paper demonstrates a new strategy for producing phosphorescent molecularly imprinted polymer (MIP) for specific recognition of a target protein. The technique provides surface graft imprinting in aqueous solutions using vinyl modified Mn-doped ZnS QDs as supports, methacrylic acid and acrylamide as functional monomers, and bovine hemoglobin as a template. The QDs act as antennae for recognition signal amplification and optical readout, and the MIP shell provides analyte selectivity and prevents interfering molecules from coming into contact with the QDs. The small particle sizes and the nontoxicity of the MIP-QDs composites allows for good dispersibility and stability in an aqueous solution. Under optimal conditions, good linear correlations were obtained for bovine hemoglobin over the concentration range from 1.0×10⁻⁷ to 5.0×10⁻⁶ mol L⁻¹ and with recoveries of 96.7-103.8% and 92.6-94.2% for urine and serum samples, respectively. The long lifetime of the MIP-QDs composites phosphorescence avoids interference due to autofluorescence and scattering of the biomatrix, facilitating composites' application for detection of bovine hemoglobin in biological fluids.

Molecularly imprinted microspheres (MIMs) for the drug diazepam and its main metabolite (nordiazepam) were prepared and used to separate the two species from urine and serum samples via molecularly imprinted solid-phase extraction. The specific binding capacity for diazepam was determined to be 1.97 mg/g, resulting in an imprinting factor of 5.8. The MIMs exhibit highly selective binding affinity for tricyclic benzodiazepines. Water-acetonitrile-acetone mixtures were used as the washing solvent and resulted in complete baseline separation, with a recovery of >87% for diazepam and of 88% for nordiazepam. The limits of detection are 21.5 and 24.5 ng/mL, respectively.

We designed and synthesized a cinchonine derivative to be used as a novel chiral monomer. It was employed in a dual role of functional monomer and cross-linking monomer, displaying multi-binding sites for the template (S)-ketoprofen. Monodisperse molecularly imprinted core-shell microspheres were prepared using surface imprinting method on silica gel. The results show a substantial synergistic effect in the enantioselective recognition, confirming our initial hypothesis. Computational simulation of the monomer and template pre-arrangement strongly supports our proposed chiral recognition mechanism for the imprinted microspheres.

Molecularly imprinted polymers (MIPs) were applied as molecular recognition elements to an electrochemical sensor for phenylephrine. A MIPs membrane was created on a glassy carbon electrode. SEM revealed a gradual change on the morphology of modified electrodes as the ratios of function monomer and cross-linking varied. When the ratio was 4:40, the surface morphology between the imprinted electrode (M-electrode) and the control electrode (N-electrode) became unambiguously different. This artificial receptor exhibited high selectivity for the template compared to closely related analogue. The response of the sensor varied in different concentration range might due to the heterogeneity of the MIPs membrane. This sensor was also used to determine phenylephrine in tablet samples.

A nanogel combined with a molecularly imprinted polymer (MIP-nanogel) receptor was prepared using the specificity determinant as a template in aqueous media. The artificial receptor can serve as the selective recognition element for angiotensins I and II and a novel way to control hypertension was investigated.

We prepared highly ordered metal ion imprinted mesoporous silica (IIMS) through co-condensation using a combination of molecular imprinting technology and traditional mesoporous materials. Copper ion is used as the template. Besides the periodic hexagonal structure, nano-sized wall thickness, and large surface area, it is found that the IIMS has highly specific recognition ability for the template. The imprinting factor of IIMS exhibits a maximum value of 3.7 at pH 2.5. The material shows fast binding kinetics for Cu2+ (complete equilibrium reach only within 5 min) and the saturation adsorption capacity reaches up to 0.39 mmol g−1. Homogeneous binding sites are confirmed by the Langmuir isothermal model and the Langmuir–Freundlich isothermal model. The heterogeneity index is 0.992 with a value similar to those found for molecularly imprinted polymers prepared using covalent imprinting. The recovery of the silica stays above 90% after six extraction–stripping cycles. Furthermore, the silica has significant potential for water treatment applications.