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A synthesis route of using cellulose as the precursor to prepare porous carbon (PC) had been established in this study. The as-prepared PC was introduced as carriers in the synthesis process of porous carbon-molecularly imprinted polymers (PC-MIPs), which greatly improved the absorption capacity of MIPs. Triazine pesticides in corn were extracted with matrix solid-phase dispersion (MSPD) using the PC-MIPs as dispersants and determined by ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Under the optimal MSPD condition for extracting six kinds of triazines (simazine, terbutryn, simetryne, prometryne, ametryn, and atrazine), the detection limits were 0.005–0.02 ng g−1, while the precisions were 1.2–5.9%, and the recoveries were 92.6–104.7%. The method has been extensively applied to analyze various corn samples. Atrazine residue (1.2 μg kg−1) was detected in one corn sample, which was lower than the maximum residual limit indicated by the Chinese stated standards (50 μg kg−1). [ABSTRACT FROM AUTHOR]

A new type of ratiometric molecularly imprinted fluorescence probe (B-CQDs@Eu/MIPs) based on biomass carbon quantum dots (B-CQDs) and europium ions (Eu3+) has been prepared to recognize and detect tetracycline (TC). In the experiment, the fluorescent material B-CQDs were prepared using passion fruit peels through microwave-assisted method, which by the meantime achieves the reuse of biomass waste. TC can block the transition of some parts of electrons in the prepared B-CQDs from the excited state to the ground state, resulting in the weakening of its blue light (Ex = 394 nm, Em = 457 nm), while TC can be chelated by Eu3+ and emit red characteristic fluorescence (Ex = 394 nm, Em = 620 nm) due to the antenna effect. Thus, a ratiometric fluorescence response to TC is the result of the combined B-CQD and Eu3+. Based on this, we established the ratiometric fluorescent molecularly imprinted (MIP) probe for the detection of TC. The prepared B-CQDs@Eu/MIPs is aimed at catching the fluorescence changes of target tetracycline (TC) sensitively with the special combination of the specific recognition cavities and TC. The linear fluorescence quenching range of TC in milk using the fluorescent probe was 25–2000 nM, and the detection limit was 7.9 nM. The recoveries of this method for TC were 94.2–103.7%, and the relative standard deviations (RSDs) were 1.5–5.3%. Owing to the predetermined nature of MIP technology and the special response of ratio fluorescence, the interference of common substances is eliminated completely, which greatly improved the selectivity of its practical applications. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymers prepared by Pickering emulsion method with lignin as stable particle were used as dispersants in matrix solid‐phase dispersion, followed by ultra high performance liquid chromatography with tandem mass spectrometry to research the degradation behavior of matrine in soil. The molecularly imprinted polymers have regular morphology and uniform particles. Moreover, the adsorption experiments and the conditions of matrix solid‐phase dispersion were discussed. With the optimal conditions of matrix solid‐phase dispersion, the recoveries of matrine were 95.4–98.2%, relative standard deviations were 0.6–5.1%, and the detection limit was 5 ng/g. Moreover, the degradation behavior of matrine in soil was researched, it indicated the half‐life of matrine was 2.7–3.2 days, and it was an environmentally friendly botanical pesticide. The method was successfully applied to separate and analyze matrine in soil samples can decrease analysis time, save organic solvents, and improve the selectivity. [ABSTRACT FROM AUTHOR]

A new magnetic molecularly imprinted polymer was coupled with ultra high performance liquid chromatography and tandem mass spectrometry for the selective determination of melamine in milk powder. The magnetic molecularly imprinted polymer has been prepared by using carbon nanotubes as the matrix, Fe3O4 particles as the magnetic ingredient, melamine as the template molecule, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker and polyvinylpyrrolidone as the dispersant. The polymer was characterized with scanning electron microscopy, Fourier transform infrared spectroscopy and a physical property measurement system. The isothermal adsorption, kinetics adsorption, and selectivity were studied to evaluate the rebinding properties of the magnetic molecularly imprinted polymer. Various parameters affecting the extraction efficiency such as the amount of polymer, extraction time, and eluting solution were evaluated. The limit of detection was 0.00075 mg/kg. The relative standard deviations of the intraday and interday precision are 0.4-2.7 and 2.3-5.1%, respectively. The proposed method was successfully applied to determine melamine in different milk powder samples from different provenances, and satisfactory recoveries of 89.0-95.6% were obtained. This method has great significance for quality control and is simple and suitable for the rapid determination of melamine in milk powder. [ABSTRACT FROM AUTHOR]

A novel dual-function material was synthesized by anchoring a molecularly imprinted polymer (MIP) layer on Mn-doped ZnS quantum dots (QDs) via a sol-gel process using 3-aminopropyltriethoxysilane (APTES) as a functional monomer, tetraethoxysilane (TEOS) as cross-linker, and nicosulfuron as template through a surface imprinting method. The amino groups in the APTES interact with the functional groups in the template molecules to form a complex through hydrogen bonding. The energy of the QDs was transferred to the complex, resulting in the quenching of the QDs and thus decreasing the fluorescence intensity, which allowed the nicosulfuron to be sensed optically. Fluorescence intensity from MIP-coated QDs was more strongly quenched by nicosulfuron than that of the non-imprinted polymer, which indicated that the MIP-coated QDs which acted as a fluorescence probe could selectively recognize nicosulfuron. Under the optimal conditions, it can detect down to 1.1 nmol L of nicosulfuron, and a linear relationship has been obtained covering the concentration range of 12-6000 nmol L. The recoveries were in the range from 89.6 to 96.5 %, and the relative standard deviations were in the range of 2.5-5.7 %. The present study established a new strategy to combine inorganic (Mn-doped ZnS QDs)-organic MIPs, which is successfully applied to determine nicosulfuron in water samples. [ABSTRACT FROM AUTHOR]

A simple method based on matrix solid phase dispersion (MSPD) using molecularly imprinted polymers (MIPs) as sorbents for selective extraction of malachite green (MG) from aquatic products was developed. The MIPs were prepared by using carbon nanotube as support, MG as template, methacrylic acid as functional monomer, ethyleneglycol dimethacrylate as crosslinker and methylene chloride as solvent. The MIPs were characterized by Fourier transform infrared spectrometry and transmission electron microscopy. The isothermal adsorption, kinetics absorption and selective adsorption experiments were carried out. We optimized the extraction conditions as follows: the ratio of MIPs to sample was 2:3, the dispersion time was 15 min, washing solvent was 4 mL 50% aqueous methanol and elution solvent was 3 mL methanol-acetic acid (98: 2, v/v). Once the MSPD process was completed, the MG extracted from aquatic products was determined by high performance liquid chromatography. The detection limit of MG was 0.7 μg kg −1 . The relative standard deviations of intra-day and inter-day were obtained in the range of 0.9%–4.7% and 3.4%–9.8%, respectively. In order to evaluate the applicability and reliability of the proposed method, it was applied to determine MG in different aquatic products samples including fish, shrimp, squid and crabs. The satisfied recoveries were in the range of 89.2%–104.6%. The results showed that this method is faster, simpler and makes extraction and purification in the same system. [ABSTRACT FROM AUTHOR]

A fast and economical method has been developed for the preconcentration of the carbamates propoxur, pirimicarb and promecarb by using magnetic molecularly imprinted polymers (m-MIPs). Propoxur was applied as the template for the analytes, and carbon nanotubes as a supporting template. The effects of the amount of magnetic sorbent, shaking time and rate, eluting solution on the extraction efficiency were studied. The processes of adsorption and desorption occur within 25 min, and the m-MIPs can be collected by applying an external magnetic field within 15 s. The m-MIPs were characterized by using FTIR, transmission electron microscopy, and with a vibrating sample magnetometer. The pesticides were quantified by HPLC with UV detection. Recoveries of spiked samples range from 90.5 to 98.6 %, and the lower detection limits range from 9.7 to 12.0 μg kg. The method is selective and convenient. The m-MIPs were successfully applied to enrich and determine the carbamates in spiked homogenates of apples, oranges and pears. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] MMIPs were prepared based on CNTs. [•] MMIPs were used for extraction of pyrethroids from fruit samples. [•] The isothermal adsorption and dynamics adsorption were studied. [•] The selectivity of MMIPs was investigated. [•] The proposed method is fast, simple and selective. [ABSTRACT FROM AUTHOR]

A simple method based on matrix solid-phase dispersion for selective extraction of anthraquinones from rhubarb samples was developed using a molecularly imprinted polymer as sorbent. The molecularly imprinted polymer was prepared using emodin as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linking agent. The polymer was characterized by scanning electron microscopy and Fourier-transform infrared spectrometry. Isothermal adsorption and dynamic adsorption experiments were performed. The best extraction conditions for anthraquinones were obtained at a ratio of molecularly imprinted polymer to sample of 1:1, a dispersion time of 5 minutes, with 5% aqueous methanol as the washing solvent, and an elution solvent of methanol-acetic acid (99:1,v/v). Once the matrix solid-phase dispersion process was optimized, the extract was reacted with 8% hydrochloric acid for hydrolysis. The anthraquinones extracted from rhubarb were determined by liquid chromatography. The detection limits of chrysophanol, emodin, physcion, and aloe-emodin were 0.23, 0.24, 0.28, and 0.27 µg mL−1, respectively. The proposed method was compared with the method in Chinese pharmacopoeia, and the results show that the extraction yield of anthraquinones obtained by molecularly imprinted polymer–matrix solid-phase dispersion method was higher. Moreover, the proposed method is faster and simpler and can achieve extraction and purification in the same system. [ABSTRACT FROM AUTHOR]

Abstract: A simple method based on magnetic molecularly imprinted polymers (MMIPs) for the separation of Sudan dyes from chilli powder samples has been developed. The MMIPs were synthesized as follows: the Fe3O4 nanoparticles were encapsulated with a SiO2 shell and functionalized with ph name="dbnd" />CH2, then the polymers were further fabricated by surface-imprinted polymerization using Sudan IV as template molecule, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linking agent. The prepared MMIPs were characterized by scanning electron microscope, Fourier transform infrared spectrometry and physical property measurement system. The isothermal absorption experiment, kinetics absorption experiment and selectivity of MMIPs were tested. The analytes were determined by high performance liquid chromatography. Under the optimal conditions, the limits of detection of the four Sudan dyes are 6.2, 1.6, 4.3 and 4.5ngg−1, respectively. The precision expressed as relative standard deviation ranging from 4.8% to 9.1% was obtained. In all three fortified levels (25, 250 and 2500ngg−1), recoveries of Sudan dyes were in the range of 79.9–87.8%. [Copyright &y& Elsevier]

Abstract: In this work, a rapid and selective method was successfully developed using the magnetic molecularly imprinted polymer (MMIP) as sorbent for the extraction of β-lactam antibiotics (BLAs) from milk samples. The MMIP has been prepared using penicillin V potassium (PENV) as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslinking agent and Fe3O4 magnetite as magnetic component. The experimental results showed that the MMIP had high affinity and selectivity toward PENV and other structurally related BLAs. The extraction process was carried out in a single step by mixing the extraction solvent, MMIPs and milk samples under ultrasonic action. When the extraction was completed, the MMIPs adsorbing the analytes were separated from the sample matrix by an external magnet. The analytes eluted from the MMIP were analyzed by liquid chromatography–tandem mass spectrometry. For achieving optimal preconcentration and reducing non-specific interactions, various parameters affecting the extraction efficiency such as extraction mode, extraction solvent, the amount of MMIPs, extraction time, washing solution and eluting solution were comprehensively evaluated. Under the optimal conditions, the detection limits of BLAs are in the range of 1.6–2.8ngmL−1. The relative standard deviations of intra- and inter-day ranging from 3.2% to 8.3% and from 3.6% to 9.8% are obtained, respectively. The method was applied to determine BLAs including PENV, amoxicillin and oxacillin in five milk samples from different provenances. The recoveries of BLAs in these samples from 71.6% to 90.7% are obtained. [ABSTRACT FROM AUTHOR]

Abstract: A simple method based on magnetic separation for selective extraction of fluoroquinolones (FQs) from environmental water samples has been developed using magnetic molecularly imprinted polymer (MMIP) as sorbent. The MMIP has been prepared using ciprofloxacin as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linking agent and Fe3O4 magnetite as magnetic component. The polymer has been characterized by scanning electron microscopy, Fourier-transform infrared spectrometry and vibrating sample magnetometry. Various parameters affecting the extraction efficiency were evaluated in order to achieve optimal concentration and reduce non-specific interactions. The analytes desorbed from the polymers were determined by liquid chromatography–tandem mass spectrometry. The matrix effect was evaluated by using different washing solvents for removing interfering compounds from the MMIPs after sample loading. Under the optimal conditions, the linearity of the method obtained is in the range of 20–2000ngL−1. The detection limits of FQs are in the range of 3.2–6.2ngL−1. The relative standard deviations of intra- and inter-day tests ranging from 2.5 to 7.2% and from 3.6 to 9.1% are obtained. In all three spiked levels (20, 100 and 200ngL−1), the recoveries of FQs are in the range of 76.3–94.2%. The proposed method was successfully applied to determine FQs including ciprofloxacin, enrofloxacin, lomefloxacin, levofloxacin, fleroxacin and sparfloxacin in different water samples, such as lake water, river water, primary and final sewage effluent. Ciprofloxacin and fleroxacin were found in primary and final sewage effluent samples with the contents in the range of 26–87ngL−1. [Copyright &y& Elsevier]

Abstract: Magnetic molecularly imprinted polymers were prepared using hydrophobic Fe3O4 magnetite as the magnetically susceptible component, oxytetracycline as template molecule, methacrylic acid as functional monomer, and styrene and divinylbenzene as polymeric matrix components. The polymers were applied to the separation of tetracycline antibiotics from egg and tissue samples. The extraction and clean-up procedures were carried out in a single step by blending and stirring the sample, extraction solvent and polymers. The analytes can be transferred from the sample matrix to the polymers directly or through the extraction solvent as medium. When the extraction was complete, the polymers adsorbing the analytes were easily separated from the sample matrix by an adscititious magnet. The analytes eluted from the polymers were determined by liquid chromatography–tandem mass spectrometry. The recoveries ranging from 72.8% to 96.5% were obtained with relative standard deviations in the range of 2.9–12.3%. The limit of detection was less than 0.2ngg−1. The feasibility of this method was validated by analysis of incurred egg and tissue samples, and the results were compared with those obtained by the classical method in which solvent extraction, centrifugation, and subsequent clean-up and concentration by solid-phase extraction were applied. The proposed method reduced the complicacy of classical method and improved the reliability of method. [Copyright &y& Elsevier]

• Mesoporous structured molecularly imprinted polymer (M-MIP) was prepared. • M-MIP was modified with restricted access material (RAM-M-MIP). • RAM-M-MIP increased adsorptive capacity and accelerated adsorption rate. • RAM-M-MIP showed good exclusion toward humic acid in soil. • RAM-M-MIP with matrix solid phase dispersion for extraction of chlorpyrifos. Mesoporous structured molecularly imprinted polymers combined with restricted access materials (RAM-M-MIPs) were synthesized in this work, then RAM-M-MIPs were used as adsorbents in matrix solid phase dispersion (MSPD) to extract chlorpyrifos residues from soil. The RAM-M-MIPs with mesoporous structure increased adsorptive capacity and accelerated adsorption rate. At the same time, the RAM-M-MIPs with restricted access function showed good exclusion effect toward humic acid in the soil. In addition, the characteristics of RAM-M-MIPs were measured and the optimal experimental conditions of MSPD were explored. In MSPD, the extraction and clean-up procedures can be finished simultaneously, which saved the extraction time. The analyte eluted from soil was determined by LC–MS/MS. The recoveries were in the range of 93.5–106.1% and the relative standard deviations were in the range of 2.8–5.7% at the spiked soil levels of 0.10–10.00 ng g−1, the detection limit was 0.015 ng g−1. Based on these analytical validation results, the developed method can be a useful method to determine chlorpyrifos in soil. [ABSTRACT FROM AUTHOR]

A new dual-emission ratiometric fluorescent probe was synthesized and successfully used for the determination of Malachite Green (MG) in fish farming water. The ratiometric fluorescent probe was successfully composited by sol-gel method using C3N4 and CdTe quantum dots as fluorescent materials combined with mesoporous molecularly imprinted polymers. MG quenches the red fluorescence of the CdTe QDs (with excitation/emission wavelengths at 350/680 nm) while the blue fluorescence of C3N4 (with excitation/emission wavelengths at 350/458 nm) remains unchanged. The change of fluorescence color and fluorescence intensity ratio can be successfully used for quantification of malachite green. In addition, the mesoporous structure has a large surface and good adsorption capacity for malachite green. The normalized intensity of fluorescence increases linearly in the 50–1000 ng·mL−1 MG concentration range, and the detection limit is 10 ng·mL−1. The imprinting factor is 3.2. The nanoprobe was applied to the determination of MG in fish farming water samples. Recoveries and relative standard deviations were 92.5–97.8% and 2.5–6.2%, respectively. [ABSTRACT FROM AUTHOR]

The authors describe a fluorescent probe for sensitive and selective determination of quercetin, an indicator for the freshness of drinks. The probe consists of silica ball encapsulated graphitic carbon nitride (g-C3N4) modified with a molecularly imprinted polymer (MIP). It was synthesized via reverse microemulsion. The resulting MIP@g-C3N4 nanocomposite was characterized by fluorescence spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction. Quercetin quenches the fluorescence of the MIP@g-C3N4 probe. The effect was used to quantify quercetin in grape juice, tea juice, black tea, and red wine by fluorometry (λexc = 350 nm, λem = 460 nm). Response is linear in the 10-1000 ng mL−1 quercetin concentration range. The detection limit is 2.5 ng mL−1, recoveries range between 90.7 and 94.1%, and relative standard deviations are between 2.1 and 5.5%.Schematic of the synthesis of the MIP@g-C3N4 by a reverse microemulsion method. The probe was applied for the selective recognition and fluorometric determination of quercetin. [ABSTRACT FROM AUTHOR]

Abstract: A novel molecularly imprinted polymer that could selectively recognize tetracyclines in milk powder was synthesized using a metal–organic framework as a support material, tetracycline as template molecule, and 3‐aminophenylboronic acid as a functional monomer and a cross‐linking agent. The novel molecularly imprinted polymer was characterized by Fourier transform infrared spectrometry, transmission electron microscopy, X‐ray diffractometry, thermogravimetric analysis, and N2 adsorption/desorption measurements. The adsorption isotherms, adsorption kinetics, adsorption thermodynamics, and selective adsorption experiments of the novel molecularly imprinted polymer to tetracycline were also studied. The novel molecularly imprinted polymer was used as dispersant of matrix solid‐phase dispersion to extraction tetracyclines. After that, the tetracyclines extracted from milk powder were determined by ultra high performance liquid chromatography with tandem mass spectrometry. Under the optimal conditions, the detection limits of tetracyclines were 0.217–0.318 ng/g. The relative standard deviations of intra‐ and interday precision ranged from 3.8 to 6.9% and from 2.8 to 7.4%, respectively. In all three concentration levels (1.0, 10, 50 ng/g), the recoveries of tetracyclines ranged from 84.7 to 93.9%. The method was successfully applied to the determination of tetracyclines in milk powder. [ABSTRACT FROM AUTHOR]

The fluorescence sensor array platform is a good choice for detection of 5-Nitroimidazole antibiotics (5-NDZs) in river water samples. However, worrisome selectivity issues inherent in fluorescent sensing units limit their general use in complex samples. In order to solve this problem, we prepared biomass carbon dots based on the catalpa walnut shells by hydrothermal method and formed molecularly imprinted polymers on the surface of carbon dots (CDs@MIPs) by sol-gel process. The cavities of CDs@MIPs enable the exposed binding sites to specifically capture the template molecules, thereby greatly improving the selectivity for 5-NDZs molecules. Different identification materials interacting to varying degrees with 5-NDZs were used to distinguish metronidazole, ornidazole, tinidazole, and secnidazole. The fingerprints were constructed with the information of fluorescence variation degree and the signals were analyzed by linear discriminant analysis. This fluorescence sensor array can sensitively identify these 5-NDZs in a wide range (20–5000 nM). In differential testing, the array platform achieved 100% recognition accuracy for 5-NDZs in buffer solutions and spiked water samples. This protocol not only provided an accurate and simple method for the detection of 5-NDZs in river water samples, but also made a positive contribution to environmental analysis. • Constructed biomass carbon dots@molecularly imprinted fluorescent probe. • Molecularly imprinted polymers improve system selectivity. • Constructed a sensor array of 3 sensing units × 4 imidazole antibiotics × 5 repeats. • Accurate identification and classification of 5-Nitroimidazole antibiotics. [ABSTRACT FROM AUTHOR]

This work has prepared a hyper-crosslinked molecularly imprinted resins (MIRs) with chloromethylated polystyrene resin as a carrier through post-crosslinked Friedel-Crafts and surface imprinting. The prepared MIRs were used for the selective separation and purification of camptothecin (CPT). The prepared MIRs are grafted with a large amount of active group phenol, which have good hydrophilicity and are favorable for application in aqueous environments. The results of Scatchard analysis and contact angle test have proved that MIRs have good adsorption capacity and excellent hydrophilicity. In addition, the results of density functional theory (DFT) analysis show that the possible interaction forces between the template molecule CPT and the functional monomer phenol are the hydrogen bonds and electrostatic attraction. Moreover, MIRs are successfully used as a solid phase extraction (SPE) adsorbent to separate and purify CPT from Camptotheca acuminata fruit. The eluent obtained by SPE is analyzed through HPLC. The detection limit for CPT is 0.23 μg mL−1. The established method preforms high the recovery of CPT (91.2–103.4%) with relative standard deviation less than 4.5%. The reusability of MIRs adsorbent is also investigated, and the adsorption efficiency is still above 95% after being recycled five times. The study provides a feasible and efficient method for selective separate and purify CPT from complicated system. [Display omitted] • Camptotheca acuminata can be used as a new resource to extract anti-tumor products. • Chloromethylated polystyrene is used as a carrier to prepare MIRs. • MIRs are prepared using Friedel-Crafts reaction and surface molecular imprinting. • The synthesis and adsorption process of MIRs are theoretically studied. • CPT is isolated and purified from Camptotheca acuminata by using MIRs. [ABSTRACT FROM AUTHOR]