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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 )., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

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 N 2 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., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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, Fe 3 O 4 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., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A novel method for the extraction of Sudan dyes including Sudan I, II, III, and IV from environmental water by magnetic titanium dioxide nanoparticles (Fe3O4@TiO2) coated with sodium dodecylsulfate (SDS) as adsorbent was reported. Fe3O4@TiO2 was synthesized by a simple method and was characterized by transmission electron microscopy, Fourier-transform infrared spectrometry, and vibrating sample magnetometer. The magnetic separation was quite efficient for the adsorption and desorption of Sudan dyes. The effect of the amount of SDS, extraction time, pH, desorption condition, maximal extraction volume, and humic acid on the extraction process were investigated. This method was employed to analyze three environmental water samples. The results demonstrated that our proposed method had wide linear range (25-5,000 ng L(-1)) with a good linearity (R (2) > 0.999) and low detection limits (2.9-7.3 ng L(-1)). An enrichment factor of 1,000 was achieved. In all three spiked levels (25, 250, and 2,500 ng L(-1)), the recoveries of Sudan dyes were in the range of 86.9-93.6 %. The relative standard deviations obtained were ranging from 2.5 to 9.3 %. That is to say, the new method was fast and effective for the extraction of Sudan dye from environmental water.

A new kind of quercetin molecularly imprinted polymer (MIP) was synthesized and applied as a selective sorbent in matrix solid-phase dispersion (MSPD) for the extraction of quercetin in Herba Lysimachiae. The MIP was prepared by surface imprinting method using quercetin as template, methacrylic acid as functional monomer, trimethylolpropane trimethacrylate as crosslinker and methanol as porogen. The selectivity of quercetin MIP was evaluated according to their recognition to quercetin and a compound with similar molecular size (bergenin). Good binding for quercetin was observed in MIP adsorption experiment. The isothermal adsorption and dynamic adsorption experiments were also carried out in this study. The best quercetin extraction conditions were as follows: the ratio of MIP to sample was 1:1, the dispersion time was 10min, washing solvent was 2% aqueous methanol and elution solvent was acetic acid-methanol (2:98, v/v). The proposed method was compared with the method used in Chinese pharmacopeia. The similar extraction yield was obtained by the two methods. Moreover, this method is faster, simpler and can realize extraction and purification procedures in the same system., (Copyright © 2013 Elsevier B.V. All rights reserved.)

A rapid and selective method was successfully developed using magnetic molecularly imprinted polymer (MMIP) as sorbent for the extraction of chloramphenicol from honey samples. The extraction process was carried out in a single step by blending and stirring the sample, extraction solvent and polymers. When the extraction was completed, the MMIPs adsorbing the analyte were separated from the sample matrix by an external magnet. The analyte eluted from the MMIPs by methanol under ultrasound assisted was analysed by liquid chromatography-tandem mass spectrometry. Various parameters affecting the extraction efficiency were evaluated for achieving optimal recovery and reducing non-specific interactions. Under optimal conditions, the detection limit of CAP was 0.047 ng g(-1). The relative standard deviations of intra- and inter-day ranging from 4.1% to 5.3% and from 2.9% to 7.1% were obtained, respectively. The method was applied to determine CAP in six honey samples. The recoveries of CAP in these samples from 84.3% to 90.9% were obtained., (Copyright © 2013. Published by Elsevier Ltd.)

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 Fe(3)O(4) nanoparticles were encapsulated with a SiO(2) shell and functionalized with -CH=CH(2), 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 4.5 ng g(-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 2500 ng g(-1)), recoveries of Sudan dyes were in the range of 79.9-87.8%., (Copyright © 2012 Elsevier B.V. All rights reserved.)

A new method based on matrix solid-phase dispersion (MSPD) coupled with liquid chromatography tandem mass spectrometry has been developed for the determination of imidacloprid in rice. The molecularly imprinted polymers were synthesized and applied as the dispersant of MSPD for selective extraction of imidacloprid from rice, while interferences originated from sample matrices were eliminated simultaneously. The satisfactory recovery of imidacloprid was obtained by the optimized extraction conditions: 1:2 as the ratio of sample to MIPs; 8 min as the dispersion time; 20% aqueous methanol as washing solvent and methanol as elution solvent. Under the optimal conditions, the linearity of imidacloprid in rice sample was achieved in the range of 10-1000 ng/g, and limit of detection was 2.4 ng/g. The relative standard deviations of intra- and inter-day tests ranging from 4.5% to 5.9% and from 4.8% to 7.1% are obtained, respectively. The proposed method was applied to the determination of imidacloprid in eight rice samples with recoveries in the range of 83.8-92.5%., (Copyright © 2012. Published by Elsevier B.V.)

The molecularly imprinted polymer (MIP) was synthesized and used as dispersant of matrix solid-phase dispersion (MSPD) for the extraction of chloramphenicol (CAP) in soil samples. The satisfactory recovery of CAP was obtained by the optimized extraction conditions: 1:2 as the ratio of sample to MIPs; 5 min as the dispersion time; 30% aqueous methanol as washing solvent and methanol as elution solvent. The CAP extracted from soil was determined by LC-MS/MS. The slight ion suppression phenomenon was observed for the CAP when the sample was cleaned up by MSPD with MIP as dispersant, when compared with C18 as MSPD dispersant, which caused significant ion suppression. LOD of CAP is 4.1 ng/g. RSDs of intra- and inter-day tests ranging from 3.1 to 6.2% and from 3.9 to 8.3% are obtained. At all three fortified levels (20, 100 and 500 ng/g), recoveries of CAP are in the range of 86.9-92.6%. The effect of ageing time of spiked soil sample on the CAP recovery was examined. The CAP recovery decreased from 91.0 to 36.9% when the ageing time changed from 1 day to 4 wk., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this study, alumina-coated magnetite nanoparticles (Fe(3)O(4)/Al(2)O(3) NPs) were synthesized, and they were applied to the analysis of sulfonamides (SAs) including sulfadiazine (SDZ), sulfamerazine (SMR), sulfamethoxazole (SMX), sulfamonomethoxine (SMM), sulfamethoxydiazine (SMD), sulfadimethoxine (SDM) and sulfaquinoxaline (SQX) in different soil samples based on magnetic solid-phase extraction (MSPE). The extraction and concentration process was carried out in a single step by mixing the extraction solvent, magnetic adsorbents and soil sample under ultrasonic action. Then, the adsorbents were isolated from the complicated matrix easily with an external magnetic field. The SAs desorbed from the adsorbents were determined by liquid chromatography-tandem mass spectrometry. Compared with traditional methods, the MSPE method simplified the operation procedure and reduced the analysis time. Under the optimum conditions, the recoveries of SDZ, SMR, SMX, SMM, SMD and SDM by analyzing the five spiked soil samples were between 71% and 93% except for SQX (42-60%). This may be due to the stronger hydrophobic property of SQX. Detection limits of SAs were between 0.37 and 6.74 ng g(-1). It was also found that the "aging" effect of SAs contaminated soil could cause the recoveries to decrease., (Copyright 2010 Elsevier B.V. All rights reserved.)

A fast and selective method was developed for the determination of sulfonamides (SAs) in honey based on magnetic molecularly imprinted polymer. The extraction was carried out by blending and stirring the sample, extraction solvent and polymers. When the extraction was complete, the polymers, along with the captured 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. Under the optimal conditions, the detection limits of SAs are in the range of 1.5-4.3 ng g(-1). The relative standard deviations of intra- and interday ranging from 3.7% to 7.9% and from 4.3% to 9.9% are obtained, respectively. The proposed method was successfully applied to determine SAs including sulfadiazine, sulfamerazine, sulfamethoxydiazine, sulfamonomethoxine, sulfadimethoxine, sulfamethoxazole and sulfaquinoxaline in different honey samples. The recoveries of SAs in these samples from 67.1% to 93.6% were obtained.

The magnetic mixed hemimicelles solid-phase extraction (MMHSPE), based on the adsorption of cation surfactant octadecyltrimethylammonium bromide (OTMABr) onto magnetite nanoparticles (Fe(3)O(4) NPs) to form mixed hemimicelles, was proposed for the preconcentration of several sulfonamides (SAs) compounds including sulfamethoxazole (SMX), sulfamethoxydiazine (SMD), sulfadimethoxine (SDM) and sulfaquinoxaline (SQX) from environmental water samples. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of OTMABr-coated Fe(3)O(4) NPs with an adscititious magnet. Mixed hemimicelles formed on the surface of Fe(3)O(4) NPs by OTMABr showed great adsorptive tendency towards analytes. The OTMABr-coated Fe(3)O(4) NPs adsorbents were easy to be prepared, low cost and environmentally friendly. A comprehensive study on the adsorption conditions such as the amount of the surfactant, the solution pH, the desorption condition and the maximum extraction sample volume were optimized. A concentration factor of 1000 was achieved by the extraction of 500 mL of environmental water samples using MMHSPE. Detection limits obtained for SMX, SMD, SDM and SQX were 0.026, 0.024, 0.033 and 0.030 microg L(-1), respectively. Good recoveries (70-102%) with low relative standard deviations (1-6%) were achieved in analyzing spiked water samples. Low concentration of SQX was found in hospital primary and final sewage effluent sample.

An automated on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) system was developed for the determination of macrolide antibiotics including erythromycin (ETM), roxithromycin (RTM), tylosin (TLS) and tilmicosin (TMC) in environmental water samples. A Capcell Pak MF Ph-1 column packed with restricted access material (RAM) was used as SPE column for the concentration of the analytes and clean-up of the sample. One milliliter water sample was injected into the conditioned SPE column and the matrix was washed out with 3 mL high purity water. By rotation of the switching valve, macrolides (MLs) were eluted in the back-flush mode and transferred to the analytical column by the chromatographic mobile phase. The matrix effect was evaluated by the directly injection LC-MS and on-line SPE-LC-MS methods. The limits of detection (LODs) and limits of quantification (LOQs) obtained are in the range of 2-6 and 7-20 ng L(-1), respectively, which means that the proposed method is suitable for trace analysis of MLs at low level concentration. The intra- and inter-day precisions are in the range of 2.9-7.2% and 3.3-8.9%, respectively. In the three fortified levels (20, 200 and 2000 ng L(-1)), recoveries of MLs ranging from 86.5% to 98.3% are obtained.

An automated system using on-line solid-phase extraction (SPE) high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was developed for the determination of tetracyclines (TCs), such as tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC), metacycline (MC), and doxycycline (DC) in honey. One milliliter diluted honey sample was injected into a conditioned C18 SPE column and the matrix was washed out with water for 3 min. By rotation of the switching valve, TCs were eluted and transferred to the analytical column by the chromatographic mobile phase. Chromatographic conditions were optimized. TCs were separated in less than 8 min with a gradient elution using a mixture of 0.8% formic acid and acetonitrile. The UV detection was performed at 365 nm. The conditions for on-line SPE, including solvent and total time for loading sample and washing matrix were also optimized. Time for extraction and separation decreased greatly. For the five kinds of TCs, the limits of detection (LODs) at a signal-to-noise of 3 ranged from 5 to 12 ng g(-1). The relative standard deviations (R.S.D.) for the determination of TCs ranged from 3.4 to 7.1% within a day and ranged from 3.2 to 8.9% in 3 days, respectively.

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 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 green and simple method was developed for determination of sulfonamides (SAs) in soil samples. The procedure was based on the microwave-assisted extraction (MAE) of SAs from soil using non-ionic surfactant Triton X-114 as the extraction medium. Then sodium chloride was added into the MAE extract and the mixture was equilibrated for some time at high temperature. The analytes in the surfactant-rich phase were concentrated with the help of centrifugation and directly analyzed by high performance liquid chromatography with UV detection. None of potentially hazardous organic solvents was used in the whole sample preparation procedure. The significant variables for the performance of extraction and concentration were studied. The limits of detection of SAs obtained are in the range of 3.2–5.7ngg−1. The relative standard deviations of intra- and inter-day tests ranging from 3.5% to 7.7% and from 4.6% to 9.5% are obtained, respectively. This method was applied to the determination of SAs in some soil samples with different characteristics. The SAs recoveries obtained at fortified level of 100ngg−1 for these samples are in the range of 81.2–93.7%. The effect of ageing time of spiked soil samples on the SAs recoveries was examined by the proposed method and a method reported in the literature. The recoveries of SAs decreased when the ageing time changed from 1 day to 4 weeks. [ABSTRACT FROM AUTHOR]

Abstract: A rapid technique based on dynamic microwave-assisted extraction (DMAE) coupled on-line with solid-phase extraction (SPE) was developed for the determination of sulfonamides (SAs) including sulfadiazine, sulfameter, sulfamonomethoxine and sulfaquinoxaline in soil. The SAs were first extracted with acetonitrile under the action of microwave energy, and then directly introduced into the SPE column which was packed with neutral alumina for preconcentration of analytes and clean-up of sample matrix. Subsequently, the SAs trapped on the alumina were eluted with 0.3% acetic acid aqueous solution and determined by liquid chromatography–tandem mass spectrometry. The DMAE parameters were optimized by the Box–Behnken design. Maximum extraction efficiency was achieved using 320W of microwave power; 12mL of extraction solvent and 0.8mLmin−1 of extraction solvent flow rate. The limits of detection and quantification obtained are in the range of 1.4–4.8ngg−1 and 4.6–16.0ngg−1 for the SAs, respectively. The mean values of relative standard deviation of intra- and inter-day ranging from 2.7% to 5.3% and from 5.6% to 6.7% are obtained, respectively. The recoveries of SAs obtained by analyzing four spiked soil samples at three fortified levels (20ngg−1, 100ngg−1 and 500ngg−1) were from 82.6±6.0% to 93.7±5.5%. The effect of standing time of spiked soil sample on the SAs recoveries was examined. The recoveries of SAs decreased from (86.3–101.9)% to (37.6–47.5)% when the standing time changed from one day to four weeks. [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]

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]