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1.
A novel molecularly imprinted polymer solid-phase extraction (MISPE) with flow-injection chemiluminescence (CL) was developed
for the determination of pazufloxacin mesilate (PZFX). The molecularly imprinted polymer (MIP) was synthesized by using PZFX
as the imprinting molecule. A glass tube packed the particles of the MIP was employed as MISPE micro-column, which was connected
into the sampling loop of the eight-way injection valve for on-line selective preconcentration and extraction of PZFX. The
eluent of acetonitrile:acetic acid (9:1, v:v) was used as carrier for eluting the adsorbed PZFX to react with the mixture
of cerium(IV) and sodium sulfite in the flow cell to produce strong CL. The relative intensity of CL was linear to PZFX concentration
in the range from 2.5 × 10−9 to 2.5 × 10−7 g mL−1. The limit of detection was 7 × 10−10 g mL−1 (3 σ) and the relative standard deviation for 5 × 10−8 g mL−1of PZFX solution was 3.7% (n = 7). This method has been applied to the determination of PZFX in human urine. 相似文献
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3.
The highly selective, fast and effective sample pretreatment technique molecularly imprinted solid-phase extraction (MISPE) can overcome the low sensitivity of the highly efficient capillary electrophoresis-UV method (CE-UV). In this work, narrowly dispersible bisphenol A (BPA)-imprinted polymeric microspheres with a high capacity factor of k′ = 6.8 and an imprinted factor of I = 6.53 were investigated as selective solid-phase extraction (SPE) sorbents for use in extraction of BPA from different sample matrices (tap water, wastewater, Yangtze River water, soil from the Yangtze River, shrimp and human urine). Washing and eluting protocols of MISPE were optimized. Under optimal conditions, recoveries of MISPE were investigated. Recoveries were basically constant and the relative standard deviation (RSD) was lower than 5.8% when loading volumes changed from 1 to 50 mL. Recoveries ranged from 71.20% to 86.23% for different sample matrices. Compared with C18 SPE, MISPE had higher selectivity and recovery for BPA. BPA was determined with good accuracy and precision in different complex samples using CE-UV coupled with MISPE. Spiked recoveries ranged from 95.20% to 105.40%, and the RSD was less than 7.2%. Because a large loading volume was achieved, the enrichment efficiency of pretreatment and the sensitivity of this method were improved. The limits of detection of this MISPE-CE-UV method for BPA in tap water, wastewater, Yangtze River water, soil from the Yangtze River, shrimp and human urine were 3.0 μg L− 1, 5.4 μg L− 1, 6.9 μg L− 1, 2.1 μg L− 1, 1.8 μg L− 1 and 84 μg L− 1, respectively. 相似文献
4.
Molecularly imprinted solid-phase extraction for the determination of fenitrothion in tomatoes 总被引:1,自引:0,他引:1
Organophosphorus insecticides are widely employed in agriculture, and residues of them can remain after harvesting or storage.
Pesticide residue control is an important task for ensuring food safety. Common chromatographic methods used in the determination
of pesticide residues in food require clean-up and concentration steps prior to quantitation. While solid-phase extraction
has been widely employed for this purpose, there is a need to improve selectivity. Due to their inherent biomimetic recognition
systems, molecularly imprinted polymers (MIP) allow selectivity to be enhanced while keeping the costs of analysis low. In
this work, a MIP that was designed to enable the selective extraction of fenitrothion (FNT) from tomatoes was synthesized
using a noncovalent imprinting approach. The polymer was prepared using methacrylic acid as functional monomer and ethyleneglycol
dimethacrylate as crosslinking monomer in dichloromethane (a porogenic solvent). The polymer was characterized by Fourier
transform infrared spectroscopy, solid-state nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and nitrogen
sorption porosimetry. The pore structure and the surface area were evaluated using the BET adsorption method. To characterize
the batch rebinding behavior of the MIP, the adsorption isotherm was measured, allowing the total number of binding sites,
the average binding affinity and the heterogeneity index to be established. A voltammetric method of quantifying FNT during
the molecularly imprinted solid-phase extraction (MISPE) studies was developed. The polymer was placed in extraction cartridges
which were then used to clean up and concentrate FNT in tomato samples prior to high-performance liquid chromatographic quantitation.
The material presented a medium extraction efficiency of 59% (for analyses performed with three different cartridges on three
days and a fortification level of 5.0 μg g−1) and selectivity when used in the preparation of tomato samples, and presented the advantage that the polymer could be reused
several times after regeneration.
Figure 相似文献
5.
Molecularly imprinted solid-phase extraction of cocaine metabolites from aqueous samples 总被引:1,自引:0,他引:1
Cocaine is a well-known drug of abuse which, when ingested nasally or by smoking, undergoes a number of biotransformation and degradation reactions. In the present work, a synthetic analogue of the cocaine metabolite benzoylecgonine was prepared and used as a template molecule in the preparation of a series of molecularly imprinted polymers (MIPs). Molecularly imprinted solid-phase extraction (MISPE) conditions were established under which benzoylecgonine in aqueous samples could be selectively extracted and quantified at clinically relevant concentrations (μg/ml). Under optimised MISPE conditions, recoveries of analyte were high (>70%) and excellent discrimination between imprinted and non-imprinted materials observed. 相似文献
6.
A novel sulfamethazine molecularly imprinted polymer (MIP)-coated stir bar for sorptive extraction of eight sulfa drugs from biological samples was prepared. The MIP-coating was about 20 μm thickness with the relative standard deviation (RSD) of 6.7% (n = 10). It was characterized by scanning electron microscope, infrared spectrum, thermogravimetric analysis, and solvent-resistant investigation, respectively. The non-imprinted polymer (NIP)-coating was used for comparison. The adsorptive capacity and selectivity of MIP-coating were evaluated in detail. The MIP-coating showed higher adsorption capability and selectivity than the NIP-coating. The saturated adsorption amount of the MIP-coating was 4.6 times over that of the NIP-coating in toluene. Sulfamethazine could be detected after the MIP-coated stir bar sorptive extraction even at a low concentration of 0.2 μg/L. The MIP-coating also exhibited selective adsorption ability to analogues of the template. A method for the determination of eight sulfa drugs in biological samples by MIP coated stir bar sorptive extraction coupled with high performance liquid chromatography (HPLC) was developed. The extraction conditions, including extraction solvent, extraction time, desorption solvent, desorption time and stirring speed, were optimized. The linear ranges were 1.0-100 μg/L and 2.0-100 μg/L for eight sulfonamides, respectively. The detection limits were within the range of 0.20-0.72 μg/L. The method was successfully applied to simultaneous multi-residue analysis of eight sulfonamides in spiked pork, liver and chicken samples with the satisfactory recoveries. 相似文献
7.
In this report, vinylimidazolium ionic liquid as a functional monomer for preparation of chlorsulfuron (CS) imprinted polymers were first studied. The imprinted materials showed high selectivity for CS, and fast kinetics so that adsorption equilibrium was achieved within 5 min. These materials have been further employed to detect trace CS from water samples by online preconcentration coupled with HPLC. The sorbent offered good linearity (0.005-30 μg L(-1), r(2)>0.99) for on-line solid-phase extraction of trace chlorsulfuron. Under the optimal experimental conditions, the recovery for chlorsulfuron was in the range of 81.0-110.1% for the water samples, with RSDs ranging from 1.2 to 7.6%. 相似文献
8.
A molecularly imprinted polymer (MIP) was prepared using monobutyl phthalate as template. The synthesis was optimized by using different porogens and functional monomers. The MIP was used as a selective sorbent in molecularly imprinted solid-phase extraction (MIP-SPE) for pre-concentration and determination of monobutyl phthalate (mBP) from the bottled water. The difference in recognition selectivity of the polymer columns was observed in HPLC system, and the effect of the mobile phase on the performance of MIP columns was also investigated. Control of the MIP-SPE process is seen as important in helping to facilitate the selective extraction of mBP from water samples. Thereafter, the choice of washing solvent, eluting solvent amount, pH of loading sample, flow rate of loading solution and the loading sample volume was presented. The optimized procedure was described as follows: 25 mL spiked aqueous solution was percolated through the MIP-SPE cartridge at the flow rate of 1.5 mL/min. After rinsing with acetonitrile/methanol mixture (1:1, v/v), the bound analyte was desorbed with 3 mL methanol. The developed MIP-SPE method was demonstrated to be applicable for the analysis of mBP in the bottled water. 相似文献
9.
Houjiang Zhou Deyong He Yufei Hu Ying Huang Dinglong Chen 《Analytica chimica acta》2004,523(2):237-242
In this paper, a novel flow chemiluminescence (CL) clenbuterol sensor based on molecularly imprinted polymer (MIP) on line enrichment nanogram clenbuterol and chemiluminescence reaction of potassium permanganate and formaldehyde in the polyphosphate enhanced by clenbuterol. Clenbuterol in the urine was selectively adsorbed on the clenbuterol-imprinted polymer, which was packed into the flow cell. The formaldehyde and the polyphosphate with potassium permanganate flowed through the flow cell and reacted with the on line adsorbed clenbuterol and produced strong CL. The results show that the sensor was reversible. The CL intensity was linear with clenbuterol concentration from 1.0 × 10−9 g/mL to 5.0 × 10−8 g/mL. The detection limit was 3.0 × 10−10 g/mL. The R.S.D. for ng/mL clenbuterol was less than 5% (n = 3). The present method offered a high selectivity and sensitivity that made the quantitative analysis of trace clenbuterol (ng/mL) in the animal urine sample. 相似文献
10.
A newly designed molecularly imprinted polymer (MIP) was synthesized and successfully utilized as a recognition element of an amperometric sensor for 2,4-dichlorophenol (2,4-DCP) detection. The MIP with a well-defined structure could imitate the dehalogenative function of the natural enzyme chloroperoxidase for 2,4-DCP. Imprinted sensor was fabricated in situ on a glassy carbon electrode surface by drop-coating the 2,4-DCP imprinted microgel suspension and chitosan/Nafion mixture. Under optimized conditions, the sensor showed a linear response in the range of 5.0–100 μmol L−1 with a detection limit of 1.6 μmol L−1. Additionally, the imprinted sensor demonstrated higher affinity to target 2,4-DCP over competitive chlorophenolic compounds than non-imprinted sensor. It also exhibited good stability and acceptable repeatability. The proposed sensor could be used for the determination of 2,4-DCP in water samples with the recoveries of 96.2–111.8%, showing a promising potential in practical application. 相似文献
11.
Development of a selective molecularly imprinted polymer-based solid-phase extraction for indomethacin from water samples 总被引:1,自引:0,他引:1
A selective molecularly imprinted solid-phase extraction (MISPE) for indomethacin (IDM) from water samples was developed.
Using IDM as template molecule, acrylamide (AM) or methacrylic acid (MAA) as functional monomer, ethylene dimethacrylate (EDMA)
as crosslinker, and bulk or suspension polymerization as the synthetic method, three molecularly imprinted polymers (MIPs)
were synthesized and characterized with a rebinding experiment. It was found that the MIP of AM-EDMA produced by bulk polymerization
showed the highest binding capacity for IDM, and so it was chosen for subsequent experiments, such as those testing the selectivity
and recognition binding sites. Scatchard analysis revealed that at least two kinds of binding sites formed in the MIP, with
the dissociation constants of 7.8 μmol L−1 and 127.2 μmol L−1, respectively. Besides IDM, three structurally related compounds — acemetacin, oxaprozin and ibuprofen — were employed for
selectivity tests. It was observed that the MIP exhibited the highest selective rebinding to IDM. Accordingly, the MIP was
used as a solid-phase extraction sorbent for the extraction and enrichment of IDM in water samples. The extraction conditions
of the MISPE column for IDM were optimized to be: chloroform or water as loading solvent, chloroform with 20% acetonitrile
as washing solution, and methanol as eluting solvent. Water samples with or without spiking were extracted by the MISPE column
and analyzed by HPLC. No detectable IDM was observed in tap water and the content of IDM in a river water sample was found
to be 1.8 ng mL−1. The extraction efficiencies of the MISPE column for IDM in spiked tap and river water were acceptable (87.2% and 83.5%,
respectively), demonstrating the feasibility of the prepared MIP for IDM extraction.
Figure Molecularly imprinted polymer-based solid-phase extraction for indomethacin 相似文献
12.
Caro E Marcé RM Cormack PA Sherrington DC Borrull F 《Journal of chromatography. A》2004,1047(2):175-180
A new polymeric sorbent synthesised by exploiting molecular imprinting technology has been used to selectively extract naphthalene sulfonates (NSs) directly from aqueous samples. In the non-covalent molecular imprinting approach used to prepare this polymer, 1-naphthalene sulfonic acid (1-NS) and 4-vinylpyridine (4-VP) were used as a template molecule and functional monomer, respectively, and both dissolved in a mixture of methanol/water (4:1) as porogen together with the cross-linker ethylene glycol dimethacrylate. The new non-covalent molecularly imprinted polymer (MIP) prepared in aqueous environment was used as a sorbent in solid-phase extraction (SPE) to selectively extract a group of naphthalene mono- and disulfonates. When one litre of a standard aqueous solution, which contained a mixture of eight NSs, was percolated through the SPE cartridge, all the NSs were retained on the MIP because of the cross-reactivity of the polymer. Recoveries were higher than 80% for all the compounds even after a clean-up step with methanol (MeOH). The MIP was also used to analyse water from the Ebro river. 相似文献
13.
Selective trace analysis of diclofenac in surface and wastewater samples using solid-phase extraction with a new molecularly imprinted polymer 总被引:3,自引:0,他引:3
A new molecularly imprinted polymer (MIP) for trace analysis of diclofenac in environmental water samples was prepared by a non-covalent protocol in which diclofenac was used as a template molecule. Diclofenac is a member of the class of drugs termed non-steroidal anti-inflammatory drugs (NSAIDs) which belong to the most frequently detected pharmaceuticals in the water-cycle in Europe. The MIP was synthesized using 2-vinylpyridine (2-VP) and ethylene glycol dimethacrylate (EGDMA) as a functional monomer and cross-linker, respectively, and bulk thermal polymerization method. 1H NMR spectroscopy was used to study the interaction between diclofenac and 2-VP mixed in toluene-d8 in pre-polymerization complex. Two non-covalent bonds were formed i.e. ionic interaction and hydrogen bonding. The binding characteristics of the MIP and diclofenac were evaluated using equilibrium binding experiments. Scatchard plot analysis revealed that two classes of binding sites were formed with dissociation constants of 55.6 μmol L−1 and 1.43 mmol L−1, respectively. Various parameters affecting the extraction efficiency of the polymers have been evaluated to achieve the selective preconcentration of diclofenac from aqueous samples and to reduce non-specific interactions. This resulted in an MISPE-LC/DAD method allowing the direct extraction of the analyte from sample matrix with a selective wash using dichloromethane/acetonitrile (94:6, v/v) followed by elution with dichloromethane/methanol (85:15, v/v). The recovery of a 100 ng diclofenac standard spiked into 200 mL of blank surface water was 96%, with good precision (RSD = 3.3%, n = 3). The MISPE was demonstrated to be applicable to the analysis of diclofenac in raw influent and final effluent wastewater samples from sewage treatment plant and revealed diclofenac concentrations of 1.31 ± 0.055 μg L−1 (n = 3) and 1.60 ± 0.049 μg L−1 (n = 3), respectively. Yielded results were in good agreement with the corresponding LC/TIS/MS/MS data obtained by an independent laboratory which were 1.40 and 1.50 μg L−1 for influent and effluent samples. 相似文献
14.
Molecularly imprinted polymers for on-line preconcentration by solid phase extraction of pirimicarb in water samples 总被引:1,自引:0,他引:1
Shun-Qin Hu Zhao-Yang WuYa-Min Zhou Zhi-Xiang CaoGuo-Li Shen Ru-Qin Yu 《Analytica chimica acta》2002,451(2):297-304
The synthesis and performance of a molecularly imprinted polymers (MIPs) as a selective solid phase extraction sorbent for the preconcentration of the carbamate pirimicarb from water samples is described. The MIP was prepared using pirimicarb as the template, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer, and using chloroform as the solvent. The detection of pirimicarb was carried out by differential pulse voltammetry (DPV) at a hanging mercury drop electrode (HMDE) in 0.1 mol l−1 HCl. Solvents of different polarities were checked for the polymer synthesis, and different experimental variables (sample pH, selection of the eluent used, eluent volume, analyte and eluent flow rates and sample volume) associated with the rebinding/extraction process were optimised. For a 25 ml sample, the process took about 13 min and resulted in a nominal enrichment factor of 50 (eluent MeOH:H2O:HAc, 7:2:1; 0.5 ml) for pirimicarb. A limit of detection of 4.1 μg l−1 was obtained, and a good reproducibility of the measurements using different MIP microcolumns was found. Furthermore, the MIP selectivity was evaluated by checking several substances with similar and different molecular structures to that of pirimicarb. As an application, pirimicarb was determined in water samples of diverse origin which were spiked at a concentration level of 71.5 μg l−1. 相似文献
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16.
Yin X Liu Q Jiang Y Luo Y 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(1):191-196
A method employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE) to pretreat samples was developed. The polymers were prepared by precipitation polymerization with andrographolide as template molecule. The structure of MIP was characterized and its static adsorption capacity was measured by the Scatchard equation. In comparison with C(18)-SPE and non-imprinted polymer (NIP) SPE column, MIP-SPE column displays high selectivity and good affinity for andrographolide and dehydroandrographolide for extract of herb Andrographis paniculata (Burm.f.) Nees (APN). MIP-SPE column capacity was 11.9±0.6 μmol/g and 12.1±0.5 μmol/g for andrographolide and dehydroandrographolide, respectively and was 2-3 times higher than that of other two columns. The precision and accuracy of the method developed were satisfactory with recoveries between 96.4% and 103.8% (RSD 3.1-4.3%, n=5) and 96.0% and 104.2% (RSD 2.9-3.7%, n=5) for andrographolide and dehydroandrographolide, respectively. Various real samples were employed to confirm the feasibility of method. This developed method demonstrates the potential of molecularly imprinted solid phase extraction for rapid, selective, and effective sample pretreatment. 相似文献
17.
In this work, a novel method is described for the determination of bromhexine in biological fluids using molecularly imprinted solid-phase extraction as the sample cleanup technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and bromhexine as the template molecule. The novel imprinted polymer was used as a solid-phase extraction sorbent for the extraction of bromhexine from human serum and urine. Various parameters affecting the extraction efficiency of the polymer have been evaluated. The optimal conditions for molecularly imprinted solid-phase extraction (MISPE) consisted of conditioning 1 mL methanol and 1 mL of deionized water at neutral pH, loading of 5 mL of the water sample (25 μg L−1) at pH 6.0, washing using 2 mL acetonitrile/acetone (1/4, v/v) and elution with 3× 1 mL methanol/acetic acid (10/1, v/v). The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of bromhexine. Results from the HPLC analyses showed that the calibration curve of bromhexine using MIP from human serum and urine is linear in the ranges of 0.5-100 and 1.5-100 μg L−1 with good precisions (3.3% and 2.8% for 5.0 μg L−1), respectively. The recoveries for serum and urine samples were higher than 92%. 相似文献
18.
Multivariate optimization of molecularly imprinted polymer solid-phase extraction applied to parathion determination in different water samples 总被引:2,自引:0,他引:2
In this work a parathion selective molecularly imprinted polymer was synthesized and applied as a high selective adsorber material for parathion extraction and determination in aqueous samples. The method was based on the sorption of parathion in the MIP according to simple batch procedure, followed by desorption by using methanol and measurement with square wave voltammetry. Plackett-Burman and Box-Behnken designs were used for optimizing the solid-phase extraction, in order to enhance the recovery percent and improve the pre-concentration factor. By using the screening design, the effect of six various factors on the extraction recovery was investigated. These factors were: pH, stirring rate (rpm), sample volume (V1), eluent volume (V2), organic solvent content of the sample (org%) and extraction time (t). The response surface design was carried out considering three main factors of (V2), (V1) and (org%) which were found to be main effects. The mathematical model for the recovery percent was obtained as a function of the mentioned main effects. Finally the main effects were adjusted according to the defined desirability function. It was found that the recovery percents more than 95% could be easily obtained by using the optimized method. By using the experimental conditions, obtained in the optimization step, the method allowed parathion selective determination in the linear dynamic range of 0.20-467.4 μg L−1, with detection limit of 49.0 ng L−1 and R.S.D. of 5.7% (n = 5). Parathion content of water samples were successfully analyzed when evaluating potentialities of the developed procedure. 相似文献
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Very severe reaction conditions are required in the conventional synthesis of molecularly imprinted polymers (MIPs), which is unfavorable to their applications in chemical separation and analysis. A simple surface molecular imprinting approach was developed to synthesize MIP-coated SiO2 micro-particles in aqueous solutions. The 1H NMR and UV-vis spectroscopic analysis indicated that via hydrogen bonding, the functional monomer (o-phenylenediamine) can associate with the target (template) 2,4-dinitrophenol (2,4-DNP), as a model compound of organic pollutants, to form a precursor in aqueous solution. The copolymerization of this precursor and the free monomer was performed in the aqueous suspension of surface modified SiO2 particles, leading to the formation of MIP-coated SiO2 micro-particles. The MIP-coated silica particles were characterized with FT-IR, TGA, and UV-vis solid-state reflection spectroscopy, and were further demonstrated to have high adsorption capacity, excellent selectivity and site accessibility for 2,4-DNP. The new absorbent was successfully used in solid-phase extraction (SPE) to selectively enrich and determine 2,4-DNP in aqueous samples. The experimental results indicated that the MIP-SPE column yielded recoveries higher than 92% with R.S.D. <2.8%, much better than the commercial C18-SPE column, which produced a recovery less than 30% with R.S.D. <3.0%. 相似文献