Synthesis of Boronate Affinity-Based Oriented Dummy Template-Imprinted Magnetic Nanomaterials for Rapid and Efficient Solid-Phase Extraction of Ellagic Acid from Food.

Ellagic acid (EA) is a natural polyphenol and possesses excellent in vivo bioactivity and antioxidant behaviors, which play an important role in the treatment of oxidative stress-related diseases, such as cancer. Additionally, EA is also known as a skin-whitening ingredient. The content of EA would determine its efficacy. Therefore, the accurate analysis of EA content can provide more information for the scientific consumption of EA-rich foods and cosmetics. Nevertheless, the analysis of EA in these samples is challenging due to the low concentration level and the presence of interfering components with high abundance. Molecularly imprinted polymers are highly efficient pretreatment materials in achieving specific recognition of target molecules. However, the traditional template molecule (EA) could not be absolutely removed. Hence, template leakage continues to occur during the sample preparation process, leading to a lack of accuracy in the quantification of EA in actual samples, particularly for trace analytes. In addition, another drawback of EA as an imprinting template is that EA possesses poor solubility and a high price. Gallic acid (GA), called dummy templates, was employed for the synthesis of MIPs as a solution to these challenges. The approach used in this study was boronate affinity-based oriented surface imprinting. The prepared dummy-imprinted nanoparticles exhibited several significant advantages, such as good specificity, high binding affinity ((4.89 ± 0.46) × 10-5 M), high binding capacity (6.56 ± 0.35 mg/g), fast kinetics (6 min), and low binding pH (pH 5.0) toward EA. The reproducibility of the dummy-imprinted nanoparticles was satisfactory. The dummy-imprinted nanoparticles could still be reused even after six adsorption-desorption cycles. In addition, the recoveries of the proposed method for EA at three spiked levels of analysis in strawberry and pineapple were 91.0-106.8% and 93.8-104.0%, respectively, which indicated the successful application to real samples.

A novel core-shell composite of PCN-222@MIPIL for ultrasensitive electrochemical sensing 4-nonylphenol.

A novel core-shell composite of PCN-222 and molecularly imprinted poly (ionic liquid) (PCN-222@MIPIL) with high conductivity and selectivity was prepared for electrochemical sensing 4-nonylphenol (4-NP). The electrical conductivities of some MOFs including PCN-222, ZIF-8, NH2-UIO-66, ZIF-67, and HKUST-1 were explored. The results indicated that PCN-222 had the highest conductivity and was then used as a novel imprinted support. PCN-222@MIPIL with core-shell and porous structure was synthesized using PCN-222 as support and 4-NP as template. The average pore volume of PCN-222@MIPIL was 0.085 m3 g-1. In addition, the average pore width of PCN-222@MIPIL was from 1.1 to 2.7 nm. The electrochemical response for PCN-222@MIPIL sensor for 4-NP was 2.54, 2.14, and 4.24 times that of non-molecularly imprinted poly (ionic liquid) (PCN-222@NIPIL), PCN-222, and MIPIL sensors, respectively, which result from superior conductivity and imprinted recognition sites of PCN-222@MIPIL. The current response of PCN-222@MIPIL sensor to 4-NP concentration from 1 × 10-4 to 10 µM presented an excellent linear relationship. The detection limit of 4-NP was 0.03 nM. The synergistic effect between the PCN-222 supporter with high conductivity, specific surface area and shell layer of surface MIPIL results in the outstanding performance of PCN-222@MIPIL. PCN-222@MIPIL sensor was adopted for detecting 4-NP in real samples and presented to be a reliable approach for determining 4-NP.

A surface protein-imprinted biosensor based on boronate affinity for the detection of anti-human immunoglobulin G.

A surface protein-imprinted biosensor was constructed on a screen-printed carbon electrode (SPCE) for the detection of anti-human immunoglobulin G (anti-IgG). The SPCE was successively decorated with aminated graphene (NH2-G) and gold nanobipyramids (AuNBs) for signal amplification. Then 4-mercaptophenylboric acid (4-MPBA) was covalently anchored to the surface of AuNBs for capturing anti-IgG template through boronate affinity binding. The decorated SPCE was then deposited with an imprinting layer generated by the electropolymerization of pyrrole. After removal of the anti-IgG template by the dissociation of the boronate ester in an acidic solution, three-dimensional (3D) cavities complementary to the anti-IgG template were formed in the imprinting layer of polypyrrole (PPy). The molecularly imprinted polymers (MIP)-based biosensor was used for the detection of anti-IgG, exhibiting a wide linear range from 0.05 to 100 ng mL-1 and a low limit of detection of 0.017 ng mL-1 (S/N = 3). In addition, the MIP-based anti-IgG biosensor also shows high selectivity, reproducibility and stability. Finally, the practicability of the fabricated anti-IgG biosensor was demonstrated by accurate determination of anti-IgG in serum sample.

Preparation of boronate-functionalized surface molecularly imprinted polymer microspheres with polydopamine coating for specific recognition and separation of glycoside template.

A facile strategy based on the boronate affinity and polydopamine coating was proposed for the preparation of surface molecularly imprinted polymer microspheres using naringin as the glycoside template. The poly(methacrylic acid-co-methyl methacrylate-co-ethyleneglycol dimethacrylate) microspheres were firstly synthesized as inner cores by suspension polymerization method, and then functionalized with 3-aminophenylboronic acid. The imprinted shell layer was obtained by self-polymerization of dopamine on the surface of boronic acid-functionalized polymer microspheres after reversible immobilization of naringin. The resultant surface molecularly imprinted microspheres showed good imprinting efficiency and recognition specificity toward the template molecule in aqueous environment. The isothermal and kinetic adsorption behaviors of the polymers were investigated. The results showed that the covalent surface imprinted microspheres possessed homogeneous recognition sites, strong adsorption affinity, and rapid rebinding kinetics. In addition, the surface imprinted microspheres were utilized as the sorbents of solid phase extraction to successfully separate and enrich naringin from Citri Grandis extract, and the recovery of naringin in eluting solution reached 84.4%.

Photoresponsive molecularly imprinted polymers based on 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid for the determination of sulfamethazine.

Core-shell structured photoresponsive molecularly imprinted polymers were developed for the determination of sulfamethazine in milk samples. The photoresponsive imprinted polymers were prepared with polymethyl methacrylate containing a mass of ester groups as core, sulfamethazine as template molecules, self-synthesized water-soluble 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid as a photoresponsive monomer, and ethylene dimethacrylate as cross-linker. Interestingly, the imprinted polymer can specifically adsorb sulfamethazine under dark and 440 nm irradiation, and release it at 365 nm. A series of adsorption experiments showed that the maximum adsorption capacity reached 12.5 mg⋅g-1 , and the adsorption equilibrium was achieved within 80 min. Moreover, the imprinted polymers display excellent reusability, with almost no performance loss after four times photo-controlled adsorption-release cycles, and the imprinted polymers have excellent selectively for sulfamethazine (imprinting factor  = 3.01). In the end, the imprinted polymers realized effective separation and enrichment of sulfamethazine in milk, with a recovery rate of over 97.5%. The material can be used as a solid-phase extractant in the process of enrichment and separation for the quantitative detection of sulfamethazine in milk samples.

Magnetic imprinted nanoparticles with synergistic tailoring of covalent and non-covalent interactions for purification and detection of procyanidin B2.

A synergistic imprinting strategy of covalent and non-covalent interactions is proposed to prepare magnetic molecularly imprinted polymers (DI-MMIPs) for highly selective separation of procyanidin B2 (PC) from grape seed samples. Dopamine and 3-amino-phenylboronic acid as cooperative functional monomers endow the imprinted sites with synergistic tailoring. Benefiting from the synergistic effect, the DI-MMIPs exhibit enhanced imprinting performance with high adsorption capacity (27.71 mg g-1), fast kinetic equilibrium time (within 30 min), outstanding selectivity (IF = 5.8, SC > 3.2), and satisfactory regeneration ability. In addition, the DI-MMIPs possess good magnetism, uniform morphology with typical core-shell structure, and stable crystallization. Furthermore, the established DI-MMIPs coupled with HPLC-UV (~ 280 nm) method has a wide linearity range of 0.05-200 µg mL-1 with correlation coefficient of 0.9997, high recoveries (> 93.1%) with RSDs from 2.9 to 5.5%, and low LOD (0.0008 µg mL-1). Consequently, this work provides an effective and easily tailored way to fabricate magnetic imprinted nanomaterials with both rapid recognition rate and high selectivity and thus holds great promise to realize the extraction and detection of PC from real samples.

Ratiometric sensor based on imprinted quantum dots-cationic dye nanohybrids for selective sensing of dsDNA.

A ratiometrically responsive sensor for dsDNA is reported, based on molecularly imprinted polymer coated quantum dots (MIP-QDs). A new platform is described for probing dsDNA by tracing the "turn on" fluorescence signal of malachite green (MG) as a cationic dye and "turn off-on" room temperature phosphorescence (RTP) signal of MIP-QDs/MG nanohybrids. The interaction between MIP-QDs surface and MG discloses an intense quenching in RTP (turning off) by a phosphorescence resonance energy transfer (PRET) process. After the addition of dsDNA, MG molecules escape from the MIP-QDs surface and intercalate into the dsDNA, resulting in the restoration of RTP intensity of MIP-QDs (turning on) and also enhancing in fluorescence of MG. This outcome hereby can be employed for the selective sensing of dsDNA via optical response. The ratio of fluorescence enhancement of MG to RTP intensity of MIP-QDs is proportional to the concentration of dsDNA in the range of 0.089-1.79 µg/mL with a detection limit (3σ/K) of 19.48 ng/mL under the optimized experimental conditions.

Synthesis of a molecularly imprinted polymer using MOF-74(Ni) as matrix for selective recognition of lysozyme.

A molecularly imprinted polymer and metal organic framework were combined to prepare protein imprinted material. MOF-74(Ni) was used as a matrix to prepare surface-imprinted material with lysozyme as a template and polydopamine as an imprinting polymer. MOF-74(Ni) not only provides a large surface area (150.0 m2/g) to modify the polymer layer with more recognition sites (Wt (Ni) = 42.24%), but also facilitates the immobilization of lysozyme by using the chelation between Ni2+ of the MOF-74(Ni) and protein. The thin polydopamine layer (10 nm) of the molecularly imprinted material (named MOF@PDA-MIP) enables surface imprinting. Benefiting from the thin polymer layer, MOF@PDA-MIP reached adsorption equilibrium within 10 min. The maximum adsorption capacity reaches 313.5 mg/g with the highest imprinting factor (IF) of 7.8. The specific recognition sites can distinguish target lysozyme from other proteins such as egg albumin (OVA), bovine serum albumin (BSA) and ribonuclease A (RNase A). The material was successfully applied to separation of lysozyme from egg white. Graphical abstract.

Mesoporous MIP-capped luminescent MOF as specific and sensitive analytical probe: application for chlorpyrifos.

Specific recognition of organophosphate pesticides (OPs) is a significant challenge for analytical researchers. Herein, surface imprinted terbium-based luminescent metal-organic framework (MOF-76) are presented as a highly specific probe for the measurement of chlorpyrifos (CP). A mesoporous molecular imprinted polymer (mMIP) layer was generated on the surface of nano-sized MOF-76 using CP, as template. The resulting mMIP-capped MOF-76 (mMIP@MOF-76) contained specific sites for adsorption of CP molecules, guaranteeing the selectivity of the designed probe. The high porosity of rod-shape MOF-76, as well as the mesoporous structure of the MIP layer improved the diffusion process and caused the high sensitivity of the probe. The detection process is based on the remarkable quenching effect of CP on the fluorescence emission of mMIP@MOF-76. Plotting the CP concentration against the fluorescence intensity (λex = 285 nm and λem = 544 nm) gave a linear curve in the concentration range 10-1000 ng mL-1 CP, with 3.41 ng mL-1 limit of detection. The designed probe was utilized for CP determination in fruit juice and environmental samples. The combination of the stable MOF-based support, as well as its remarkable fluorescence features and specific MIP sites, led to a highly selective and ultrasensitive detection system.Graphical abstract.

Carbon dots-embedded epitope imprinted polymer for targeted fluorescence imaging of cervical cancer via recognition of epidermal growth factor receptor.

A carbon dots-embedded epitope imprinted polymer (C-MIP) was fabricated for targeted fluorescence imaging of cervical cancer by specifically recognizing the epidermal growth factor receptor (EGFR). The core-shell C-MIP was prepared by a reverse microemulsion polymerization method. This method used silica nanoparticles embedded with carbon dots as carriers, acrylamide as the main functional monomer, and N-terminal nonapeptides of EGFR modified by palmitic acid as templates. A series of characterizations (transmission electron microscope, dynamic light scattering, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, zeta potential, and energy dispersive X-ray spectroscopy) prove the successful synthesis of C-MIP. The fluorescence of C-MIP is quenched by the epitopes of EGFR due to the specific recognition of epitopes of EGFR through their imprinted cavities (analytical excitation/emission wavelengths, 540 nm/610 nm). The linear range of fluorescence quenching is 2.0 to 15.0 µg mL-1 and the determination limit is 0.73 µg mL-1. The targeted imaging capabilities of C-MIP are demonstrated through in vitro and in vivo experiments. The laser confocal imaging results indicate that HeLa cells (over-expression EGFR) incubated with C-MIP show stronger fluorescence than that of MCF-7 cells (low-expression EGFR), revealing that C-MIP can target tumor cells overexpressing EGFR. The results of imaging experiments in tumor-bearing mice exhibit that C-MIP has a better imaging effect than C-NIP, which further proves the targeted imaging ability of C-MIP in vivo. Graphical abstract An oriented epitope imprinted polymer embedded with carbon dots was prepared for the determination of the epitopes of epidermal growth factor receptor and targeted fluorescence imaging of cervical cancer.

Advances in the development of molecularly imprinted polymers for the separation and analysis of proteins with liquid chromatography.

This review documents recent advances in the design, synthesis, characterization, and application of molecularly imprinted polymers in the form of monoliths and particles/beads for the use in the separation and analysis of proteins with solid-phase extraction or liquid chromatography. The merits of three-dimensional molecular imprinting, whereby the molecular template is randomly embedded in the polymer, and two-dimensional imprinting, in which the template is confined to the surface, are described. Target protein binding can be achieved by either using the entire protein as a template or by using a protein substructure as template, that is, a peptide, as in the "epitope" approach. The intended approach and strategy then determine the choice of polymerization method. A synopsis has been provided on methods used for the physical, chemical, and functional characterizations and associated performance evaluations of molecularly imprinted and nonimprinted control polymers, involving a diverse range of analytical techniques commonly used for low and high molecular mass analytes. Examples of recent applications demonstrate that, due to the versatility of imprinting methods, molecularly imprinted monoliths or particles/beads can be adapted to protein extraction/depletion and separation procedures relevant to, for example, protein biomarker detection and quantification in biomedical diagnostics and targeted proteomics.

Preparation of core-shell magnetic molecularly imprinted polymer nanoparticle for the rapid and selective enrichment of trace diuron from complicated matrices.

A novel magnetic MIPs (DUMIPs) was prepared by surface molecular imprinting method using superparamagnetic core-shell nanoparticle (Fe3O4@SiO2) as the sacrificial support matrix, herbicide diuron as template, α-methacrylic acid as the functional monomer, trimethylolpropane trimethacrylate as the crosslinker, azobisisobutyronitrile as the initiator, and acetonitrile as the porogen. Highly cross-linked porous surface and excellent magnetic property were characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and vibrating sample magnetometer, respectively. The adsorption capacity of DUMIPs was 8.1 mg g-1, 2.6-fold over its corresponding non-imprinted polymers (DUNIPs). The adsorption in DUMIPs was considered as multilayer adsorption and posed high affinity to diuron, due to the better fitting to Freundilich isotherm. Competitive recognition study demonstrated DUMIPs had highly selective binding diuron. DUMIPs, as an influential sorbent has been used for selective extraction of diuron from environmental samples (paddy field water, paddy soil and grain seedlings) and the elution was determined by high efficiency liquid chromatography (HPLC). In this analytical method, various factors affecting the extraction efficiency such as pH, sorbent dosage, utilization efficiency and volumes of eluent were simultaneously investigated. Under the optimal conditions, the linearity of the method obtained is in the range of 0.02-10.0 mg L-1. The limit of detection is 0.012 mg L-1. In four spiked levels (0.04, 0.2, 1.0, and 4.0 mg kg-1), the recoveries of diuron in real samples are in the range of 83.56%-116.10% with relative standard deviations in the range of 1.21-6.81%. Importantly, compared to C18-SPE column, the MMIPs exhibited convenient separation by external magnetic field, strong clean-up capacity, and selective enrichment for diuron. Thus, the DUMIPs-based method is great potential for efficient sample preparation in the determination of trace amounts of diuron residues in complex matrices.

A Probe for Fluorescence Detection of the Acetylcholinesterase Activity Based on Molecularly Imprinted Polymers Coated Carbon Dots.

This paper presents a new probe for fluorescence detection of the acetylcholinesterase (AChE) activity based on molecularly imprinted polymer (MIP) coated carbon dots (C-dots) composite. The C-dots were hydrothermally synthesized with grafted silica surface and sealed with molecularly imprinted polymers in silica pores (MIP@C-dots) in situ. Removed the original template molecules, the MIP@C-dots composite exhibits quite high selectivity for acetylthiocholine (ACh). With AChE, its substrate ACh will be hydrolyzed into thiocholine and the fluorescence signals exhibit a dramatic decrease at 465 nm, Under optimal conditions, the fluorescent probe shows sensitive responses to AChE in the range of 0.01-0.6 mU/mL. The detection limits of AChE are as low as 3 µU/mL. These experiments results validate the novel fluorescent probe based on MIP@C-dots composite, paving a new way to evaluation of AChE activity and Screening inhibitors.

CdTe quantum dots coated with a molecularly imprinted polymer for fluorometric determination of norfloxacin in seawater.

A fluorescent nanoprobe consisting of CdTe quantum dots (QDs) and coated with molecularly imprinted layers was prepared and successfully applied to the determination of norfloxacin (NOR) in seawater and wastewater samples. The 3-mercaptopropionic acid capped QDs were prepared and then covered with a protective silica shell. A molecularly imprinted layer was finally synthesized around the silanized QDs using 3-aminopropyltriethoxysilane as functional monomer and norfloxacin as the template. Compared with the non-imprinted polymer, the fluorescence of the nanoprobe with imprinted polymer (measured at excitation/emission wavelengths of 300/596 nm) is strongly reduced in the presence of NOR, and the imprinting factor is 8.8. Under the optimal experimental conditions, the detection limit of the nanoprobe is 0.18 µM, and response is linear between 0.5 - 28 µM of NOR. The relative standard deviation of the detection of NOR is <7.2%. In order to evaluate the practicality of the probe, wastewater and seawater samples spiked with norfloxacin were analyzed by this method, and recoveries ranged from 96.2 - 106.0%. Graphical abstract Schematic presentation and fluorescence spectrum of fluorescent nanoprobe with selectivity for norfloxacin (NOR). CdTe quantum dots (QDs) are used as fluorescent carriers, 3-aminopropyltriethoxysilane (APTES) as template molecules, tetraethyl orthosilicate (TEOS) as crosslinking agent, and aqueous ammonia as initiator.

Functional organic material for roxarsone and its derivatives recognition via molecular imprinting.

Roxarsone, one of feed add drugs containing arsenic, has been most widely used in poultry and swine industry. Roxarsone discharged into the environment has caused serious pollution problem. Herein, a reusable functional material for selective recognition and adsorption of roxarsone and its derivatives were designed and synthesized. The interaction mechanism is based on acid-base interaction and surface molecular imprinting. Dual functionalized core-shell structure with silica gel as the core was prepared to use as carrier for surface molecularly imprinted polymers. Surface molecularly imprinted polymers for roxarsone was successfully designed and synthesized using 3-aminopropyltriethoxysilane and methyl acryloyloxypropyltriethoxy silane as functional monomers, Ethylene glycol dimethacrylate as crosslinker, Azobisisobutyronitrile as initiator, acetonitrile as solvent. Binding study showed that the recognition selectivity for roxarsone and its derivatives can be significantly improved (3.5-4 folds) with molecular imprinting. Moreover, the prepared functional material for selective recognition and adsorption of Roxarsone was reusable for multiple times without significant decreasing their adsorption capacities.

Molecularly imprinted polymers synthesized via template immobilization on fumed silica nanoparticles for the enrichment of phosphopeptides.

Phosphorylation is a protein post-translational modification (PTM) that plays an important role in cell signaling, cell differentiation, and metabolism. The hyper phosphorylated forms of certain proteins have been appointed as biomarkers for neurodegenerative diseases, and phosphorylation-related mutations are important for detecting cancer pathways. Due to the low abundance of phosphorylated proteins in biological fluids, sample enrichment is beneficial prior to detection. Thus, a need to find new strategies for enriching phosphopeptides has emerged. Molecularly imprinted polymers (MIPs) are synthetic polymeric materials manufactured to exhibit affinity for a target molecule. In this study, MIPs have been synthesized using a new approach based on the use of fumed silica as sacrificial support acting as solid porogen with the template (phosphotyrosine) immobilized on its surface. Phosphotyrosine MIPs were tested against a mixture of peptides and phosphopeptides by performing micro-solid phase extraction using MIPs (µMISPE) packed in a pipette tip. First, the capability of the materials to preferentially enrich phosphopeptides was evaluated. In a next step, the enrichment of phosphopeptides from a whole-cell lysate of human embryonic kidney (HEK) 293T cells was performed. The eluates were analyzed using MALDI-MS in the first case and with nano-HPLC-ESI-MS/MS in the second case. The results showed that the MIPs provided affinity for phosphopeptides, binding preferentially to multi-site phosphorylated peptides. The MIPs could enrich phosphopeptides in over 10-fold compared with the number of phosphopeptides found in a cell lysate without enrichment.

Efficient vitamin B12-imprinted boronate affinity magnetic nanoparticles for the specific capture of vitamin B12.

Vitamin B12 (VB12) has an important function in human physiology. However, analysis of VB12 at natural levels in foods or biological samples is difficult because of its very low concentration level and the presence of high-abundance components which can interfere with the measuring system. Thus, it is essential to develop efficient and selective enrichment approaches for VB12. Molecularly imprinted polymers (MIPs) have important applications from separation and sensing to catalysis. However, there is no report on the preparation of MIPs for VB12. Here, we use boronate affinity-based oriented surface imprinting to prepare MIPs for VB12. A VB12 template was first covalently immobilized onto the surface of boronic acid functionalized magnetic nanoparticles. Subsequently, a thin imprinting coating of poly(2-anilinoethanol) was formed to cover the substrate surface via in-water polymerization. After removing the template, 3D cavities complementary to the molecular size and shape of the template were formed in the imprinting layer. The imprinting coating was highly hydrophilic and presented limited residual boronic acid, thus non-specific binding was avoided. The prepared MIPs exhibited several highly favorable features, including excellent specificity, high binding strength and low binding pH. The prepared MIPs were successfully applied to the analysis of VB12 in human milk.

Efficient synthesis of molecularly imprinted polymers with bio-recognition sites for the selective separation of bovine hemoglobin.

We developed a facile approach to the construction of bio-recognition sites in silica nanoparticles for efficient separation of bovine hemoglobin based on amino-functionalized silica nanoparticles grafting by 3-aminopropyltriethoxylsilane providing hydrogen bonds with bovine hemoglobin through surface molecularly imprinting technology. The resulting amino-functionalized silica surface molecularly imprinted polymers were characterized using scanning electron microscope, transmission electronic microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Results showed that the as-synthesized imprinted polymers exhibited spherical morphology and favorable thermal stability. The binding adsorption experiments showed that the imprinted polymers can reach equilibrium within 1 h. The Langmuir isotherm and pseudo-second-order kinetic model fitted the adsorption data well. Meanwhile, the imprinted polymers possessed a maximum binding capacity up to 90.3 mg/g and highly selectivity for the recognition of bovine hemoglobin. Moreover, such high binding capacity and selectivity retained after eight cycles, indicating the good stability and reusability of the imprinted polymers. Finally, successful application in the selective recognition of bovine hemoglobin from a real bovine blood sample indicated that the imprinted polymers displayed great potentials in efficient purification and separation of target proteins.

Highly selective and efficient imprinted polymers based on carboxyl-functionalized magnetic nanoparticles for the extraction of gallic acid from pomegranate rind.

With the combined surface imprinting technique and immobilized template strategy, molecularly imprinted magnetic nanoparticles were successfully prepared and coupled with high-performance liquid chromatography to selectively separate and determine gallic acid from the pomegranate rind. On the surface of carboxyl-functionalized magnetic nanospheres, thin imprinting shells were formed using dopamine as monomer and crosslinker. The characteristics, polymerization conditions, and adsorption performances of the resultant nanomaterials were investigated in detail. In addition of good crystallinity, satisfactory magnetism, and uniform morphology of the obtained polymers, they had rapid binding kinetics, high adsorption capacity, and favorable reusability. In the mixed solution of four hydroxybenzoic acids, the prepared nanomaterials have an excellent selectivity to gallic acid with an imprinting factor of as high as 17.5. Therefore, the polymers have great potentials in specific extraction and enrichment of gallic acid from the complex natural resources.

Molecularly imprinted polymers for the detection of illegal drugs and additives: a review.

This review (with 154 refs.) describes the current status of using molecularly imprinted polymers in the extraction and quantitation of illicit drugs and additives. The review starts with an introduction into some synthesis methods (lump MIPs, spherical MIPs, surface imprinting) of MIPs using illicit drugs and additives as templates. The next section covers applications, with subsections on the detection of illegal additives in food, of doping in sports, and of illicit addictive drugs. A particular focus is directed towards current limitations and challenges, on the optimization of methods for preparation of MIPs, their applicability to aqueous samples, the leakage of template molecules, and the identification of the best balance between adsorption capacity and selectivity factor. At last, the need for convincing characterization methods, the lack of uniform parameters for defining selectivity, and the merits and demerits of MIPs prepared using nanomaterials are addressed. Strategies are suggested to solve existing problems, and future developments are discussed with respect to a more widespread use in relevant fields. Graphical abstract This review gives a comprehensive overview of the advances made in molecularly imprinting of polymers for use in the extraction and quantitation of illicit drugs and additives. Methods for syntheses, highlighted applications, limitations and current challenges are specifically addressed.