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1.
Peter A. Lieberzeit Abdul Rehman Naseer Iqbal Bita Najafi Franz L. Dickert 《Monatshefte für Chemie / Chemical Monthly》2009,391(8):947-952
Abstract An e-nose comprised of six sensing channels each coated with a molecularly imprinted polymer (MIP) selectively interacting
with alpha-pinene, thymol, estragol, linalool, and camphor, respectively, was designed. When applying it for continuous online
surveillance of terpenes emitted from basil and peppermint leaves as a criterion of freshness, it very appreciably reproduced
the emanation patterns from these plants as shown by GC-MS. Chromatography yielded a variety of terpenes in a concentration
range below 70 ppm. Trend lines obtained from the e-nose were corroborated by GC-MS and also appreciably fit the usual conduct
of these plants as observable by the human nose.
Graphical abstract
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2.
Environmental analysis is a potential key application for chemical sensors owing to their inherent ability to detect analytes
on-line and in real time in distributed systems. Operating a chemosensor in a natural environment poses substantial challenges
in terms of ruggedness, long-term stability and calibration. This article highlights current trends of achieving both the
necessary selectivity and ruggedness: one way is deploying sensor arrays consisting of robust broadband sensors and extracting
information via chemometrics. If using only a single sensor is desired, molecularly imprinted polymers offer a straightforward
way for designing artificial recognition materials. Molecularly imprinted polymers can be utilized in real-life environments,
such as water and air, aiming at detecting analytes ranging from small molecules to entire cells.
Figure 相似文献
3.
Lieberzeit PA Afzal A Glanzing G Dickert FL 《Analytical and bioanalytical chemistry》2007,389(2):441-446
Titanate sol–gel layers imprinted with midchain carbonic acids have proven highly useful for detecting engine oil degradation
processes owing to selective incorporation of oxidised base oil components. Synthesising the material from TiCl4 in CCl4 and precipitating with water leads to imprinted TiO2 nanoparticles with a diameter of 200–300 nm. Replacing the water by a 1 M ammonium hydroxide solution reduces the average
particle size to 50–100 nm with retention of the interaction capabilities. Experiments with the latter solution revealed that
the 100-nm particles take up substantially more analyte, indicating a size-dependent phenomenon. As the number of interaction
sites within each material is the same, this cannot be a consequence of thermodynamics but must be one of accessibility. The
sensor characteristic of water-precipitated particles towards engine oil degradation products shows substantially increased
sensitivity and dynamic range compared with the corresponding thin films. Coating quartz crystal microbalances with such nanoparticle
materials leads to engine oil degradation sensors owing to incorporation of acidic base oil oxidation products. Interaction
studies over a large range of layer thicknesses revealed that both the absolute signal and the steepness of the correlation
between the sensor signal and the layer height is 2 times higher for the particles.
Figure Generation of molecularly imprinted sol–gel nanoparticles 相似文献
4.
Zhixiang Xu Shuang Chen Wei Huang Guozhen Fang Hua Pingzhu Shuo Wang 《Analytical and bioanalytical chemistry》2009,393(4):1273-1279
Estrone is one of the important potential endocrine-disrupting compounds, and the sensitive and reliable analytical methods
for the determination of estrone are required for the assurance of human health. In this paper, using estrone as template
molecule, 3-aminopropyltriethoxysilane as function monomer, and tetraethoxysilicane as cross-linker, a highly selective molecularly
imprinted microsphere was synthesized by surface molecular imprinting technique combined with a sol–gel process. The imprinted
material was characterized by the Fourier transform infrared and static adsorption experiments, and the results showed that
it exhibited good recognition and selective ability for estrone. A novel method for separation and determination of trace
estrone in environmental sample was developed using on-line molecularly imprinted solid-phase extraction coupled to high-performance
liquid chromatography. With a sample loading flow rate of 2.6 mL min−1 for a 9.6-min extraction, the enrichment factor obtained by the slopes of the linear portion in comparison with the direct
injection of 10 μL standard sample solution was 1,045. The detection limit (S/N = 3) was 5.7 ng L−1, and the relative standard deviations for nine replicate extractions of 5.0 μg L−1 estrone was less than 10.0%. This method was evaluated for quantitative determination of estrone in well and lake water samples
spiked at two levels (0.5 and 1.0 μg L−1) with recoveries ranging from 86% to 95%.
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5.
Dickert FL Lieberzeit PA Achatz P Palfinger C Fassnauer M Schmid E Werther W Horner G 《The Analyst》2004,129(5):432-437
Six QCM resonators forming a sensor array were coated with different molecularly imprinted polymers for the on-line monitoring of composting procedures. Four key analytes are traced, namely water, 1-propanol, ethyl acetate and limonene. Trendlines obtained on-line by the sensor during measurements in a commercial composter give a distinct pattern: the signal for the alcohols first decreases according to an increase in ethyl acetate concentration, and increases again, when obviously no more acetic acid is formed. Limonene is detected in later stages of composting. Similar trends could also be observed by GC-MS. Additionally, chromatographic and sensor data for limonene could be correlated with each other. 相似文献
6.
Six molecularly imprinted polymers (MIPs) of erythromycin (ERY) were prepared by noncovalent bulk polymerization using methacrylic
acid (MAA) as the functional monomer. On the basis of binding analysis, the MIPs with 1:2 optimum ratio of template to MAA
were selected for subsequent scanning electron microscopy and Brunauer–Emmett–Teller analyses, which indicated that the MIPs
had more convergent porous structures than the nonimprinted polymers. The equilibrium binding experiments showed that the
binding sites of MIPs were heterogeneous, with two dissociation constants of 0.005 and 0.63 mg mL−1, respectively. Furthermore, the performance of the MIPs as solid-phase extraction (SPE) sorbents was evaluated, and the selectivity
analysis showed that the MIPs could recognize ERY with moderate cross-reactivity for other macrolides. The overall investigation
of molecularly imprinted SPE for cleanup and enrichment of the ERY in pig muscle and tap water confirmed the feasibility of
utilizing the MIPs obtained as specific SPE sorbents for ERY extraction in real samples.
Figure Schematic diagram of the preparation and application of the erythromycin imprinted molecularly imprinted polymers
Suquan Song and Aibo Wu contributed equally to this work. 相似文献
7.
Adrián Alvarez-Diaz José M. Costa Rosario Pereiro Alfredo Sanz-Medel 《Analytical and bioanalytical chemistry》2009,394(6):1569-1576
A highly selective molecularly imprinted polymer (MIP) for the recognition of the pesticide carbaryl in water has been synthesized
using halogenated bisphenol A compounds as one of the polymeric precursors and carbaryl as the template molecule. On the basis
of the heavy-atom effect, both the brominated and the iodinated MIPs allowed analyte detection by room-temperature-phosphorescence
measurements. In the presence of an oxygen scavenger (sodium sulphite) the halide, included in the polymeric structure, induced
efficient room-temperature phosphorescence of the analyte (once it had been selectively retained by the MIP). The MIP cavity
can be easily regenerated for subsequent sample injections with 2 mL methanol. The optosensing system developed has demonstrated
high selectivity for carbaryl, even in the presence of other luminophores that could be unspecifically adsorbed onto the MIP
surface. Under optimal experimental conditions, the detection limit for the target molecule was 4 μg/L (3-mL sample injection
volume), and the linear range extended up to 1 mg/L of the analyte. Good reproducibility was achieved (a relative standard
deviation of 3% was obtained for ten replicates of 150 μg/L carbaryl). The synthesized sensing material showed good stability
for at least 3 months after preparation. Finally, the applicability to carbaryl determination in real samples was evaluated
through the successful determination of the pesticide in spiked mineral and tap water samples.
Figure Schematic diagram of carbaryl recognition process by an halogenated molecularly imprinted polymer for room temperature phosphorescence
detection of the analyte. 相似文献
8.
A rapid, specific, and sensitive method has been developed using molecularly imprinted polymers (MIPs) as solid-phase extraction
sorbents for extraction of trace tetracycline antibiotics (TCs) in foodstuffs. MIPs were prepared by precipitation polymerization
using tetracycline as the template. Under the optimal condition, the imprinting factors for MIPs were 4.1 (oxytetracycline),
7.0 (tetracycline), 7.4 (chlortetracycline), 7.7 (doxycycline), respectively. Furthermore, the performance of MIPs as solid-phase
extraction sorbents was evaluated and high extraction efficiency of molecularly imprinted solid-phase extraction (MISPE) procedure
was demonstrated. Compared with commercial sorbents, MISPE gave a better cleanup efficiency than C18 cartridge and a higher
recovery than Oasis HLB cartridge. Finally, the method of liquid chromatography–tandem mass spectrometry coupled with molecular-imprinted
solid-phase extraction was validated in real samples including lobster, duck, honey, and egg. The spiked recoveries of TCs
ranged from 94.51% to 103.0%. The limits of detection were in the range of 0.1–0.3 μg kg−1.
Chromatograms obtained by direct injection of the spiked egg extracts (5 × 10-3 mmol L−1) and purification with MISPE 相似文献
9.
A new molecularly imprinted polymer for selective extraction of cotinine from urine samples by solid-phase extraction 总被引:1,自引:0,他引:1
Cotinine, the main metabolite of nicotine in human body, is widely used as a biomarker for assessment of direct or passive
exposure to tobacco smoke. A method for molecularly imprinted solid-phase extraction (MISPE) of cotinine from human urine
has been investigated. The molecularly imprinted polymer (MIP) with good selectivity and affinity for cotinine was synthesized
using cotinine as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as
the cross-linker. The imprinted polymer was evaluated for use as a SPE sorbent, in tests with aqueous standards, by comparing
recovery data obtained using the imprinted form of the polymer and a non-imprinted form (NIP). Extraction from the aqueous
solutions resulted in more than 80% recovery. A range of linearity for cotinine between 0.05 and 5 μg mL−1 was obtained by loading 1 mL blank urine samples spiked with cotinine at different concentrations in acetate buffer of pH
9.0, and by using double basic washing and acidic elution. The intra-day coefficient of variation (CV) was below 7% and inter-day
CV was below 10%. This investigation has provided a reliable MISPE–HPLC method for determination of cotinine in human urine
from both active smokers and passive smokers.
Figure 相似文献
10.
Selective solid-phase extraction of bisphenol A using molecularly imprinted polymers and its application to biological and environmental samples 总被引:1,自引:0,他引:1
Zhang JH Jiang M Zou L Shi D Mei SR Zhu YX Shi Y Dai K Lu B 《Analytical and bioanalytical chemistry》2006,385(4):780-786
Molecularly imprinted polymers (MIPs) were prepared using bisphenol A (BPA) as a template by precipitation polymerization. The polymer that had the highest binding selectivity and ability was used as solid-phase extraction (SPE) sorbents for direct extraction of BPA from different biological and environmental samples (human serum, pig urine, tap water and shrimp). The extraction protocol was optimized and the optimum conditions were as follows: conditioning with 5 mL methanol–acetic acid (3:1), 5 mL methanol, 5 mL acetonitrile and 5 mL water, respectively, loading with 5 mL aqueous samples, washing with 1 mL acetonitrile, and eluting with 3 mL methanol. MIPs can selectively recognize, effectively trap and preconcentrate BPA over a concentration range of 2–20 μM. Recoveries ranged from 94.03 to 105.3 %, with a relative standard deviation lower than 7.9 %. Under the optimal condition, molecularly imprinted SPE recoveries of spiked human serum, pig urine, tap water and shrimp were 65.80, 82.32, 76.00 and 75.97 %, respectively, when aqueous samples were applied directly. Compared with C18 SPE, a better baseline, better high-performance liquid chromatography separation efficiency and higher recoveries were achieved after molecularly imprinted SPE.
相似文献
11.
Yan Xiong Jing Xu Jian-Wei Wang Ya-Feng Guan 《Analytical and bioanalytical chemistry》2009,394(3):919-923
We have prepared a novel fiber-optic evanescent wave sensor (FEWS) for dissolved oxygen (DO) detection. The sensor fabrication
was based on coating a decladded portion of an optical fiber with a microporous coating, which was prepared from 3,3,3-trifluoropropyltrimethoxysilane
and n-propyltrimethoxysilane. The fluorophores were immobilized in the porous coating and excited by the evanescent wave field
produced on the core surface of the optical fiber. The sensitivity of the sensor was quantified by the ratio of the fluorescence
intensities in pure deoxygenated (I
0) and in pure oxygenated environments (I). Results show that the quenching response of DO is increased with the enhancement of the coating surface hydrophobicity
using the presented hybrid fluorinated ORMOSILs. The calibration curve of I
0/I to [O2] is linear from 0 to 40 ppm and the detection limit is 0.05 ppm (3σ) with a short response time of 15 s for DO detection.
Figure 相似文献
12.
Feng QZ Zhao LX Yan W Ji F Wei YL Lin JM 《Analytical and bioanalytical chemistry》2008,391(3):1073-1079
Highly sensitive flow-injection chemiluminescence (CL) combined with molecularly imprinted solid-phase extraction (MISPE)
has been used for determination of 2,4-dichlorophenol (2,4-DCP) in water samples. The molecularly imprinted polymer (MIP)
for 2,4-DCP was prepared by non-covalent molecular imprinting methods, using 4-vinylpyridine (4-VP) and ethylene glycol dimethacrylate
(EGDMA) as the monomer and cross-linker, respectively. 2,4-DCP could be selectively adsorbed by the MIP and the adsorbed 2,4-DCP
was determined by its enhancing effect on the weak chemiluminescence reaction between potassium permanganate and luminol.
The enhanced CL intensity was linear in the range from 1 × 10−7 to 2 × 10−5g mL−1. The LOD (S/N = 3) was 1.8 × 10−8g mL−1, and the relative standard deviation (RSD) was 3.0% (n = 11) for 1.4 × 10−6g mL−1. The proposed method had been successfully applied to the determination of 2,4-DCP in river water.
Figure Effect of 4-VP content on the ultraviolet spectrum of 2,4-DCP in chloroform 相似文献
13.
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
14.
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
15.
Subash C. B. Gopinath Koichi Awazu Makoto Fujimaki Katsuaki Sugimoto Yoshimichi Ohki Tetsuro Komatsubara Junji Tominaga Penmetcha K. R. Kumar 《Analytical and bioanalytical chemistry》2009,394(2):481-488
Biological self-assembly is a natural process that involves various biomolecules, and finding the missing partner in these
interactions is crucial for a specific biological function. Previously, we showed that evanescent-field-coupled waveguide-mode
sensor in conjunction with a SiO2 waveguide, the surfaces which contain cylindrical nanometric holes produced by atomic bombardment, allowed us to detect efficiently
the biomolecular interactions. In the present studies, we showed that the assembly of biomolecules can be monitored using
the evanescent-field-coupled waveguide-mode biosensor and thus provide a methodology in monitoring assembly process in macromolecular
machines while they are assembling.
Evanescent-field-coupled waveguide-mode sensor
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Tse Sum Bui B Belmont AS Witters H Haupt K 《Analytical and bioanalytical chemistry》2008,390(8):2081-2088
A β-estradiol receptor binding mimic was synthesised using molecular imprinting. Bulk polymers and spherical polymer nanoparticles
based on methacrylic acid and ethylene glycol dimethacrylate as the functional monomer and crosslinker, respectively, were
prepared in acetonitrile. The selectivity was evaluated by radioligand binding assays. The imprinted polymers were very specific
to β-estradiol since the control polymers bound virtually none of the radioligand. The bulk polymer was then employed to screen
endocrine disrupting chemicals. Structurally related steroids like α-estradiol, estrone and ethynylestradiol showed, respectively,
14.0, 5.0 and 0.7% of relative binding to the β-estradiol polymer, whereas most unrelated chemicals did not bind at all. These
results are compared to those obtained with a bioassay using stably transfected yeast cells in culture bearing the human estrogen
receptor. The receptor was activated by several estrogen-like chemicals and to a lesser extent by some structurally related
chemicals.
Figure A molecularly imprinted polymer that was a synthetic receptor for beta-estradiol was used for the screening of endocrine disrupting
chemicals that are structurally related or unrelated to beta-estradiol. The results were compared with the recognition of
the compounds by the biological estrogen receptor expressed in yeast cells. Related steroids like alpha-estradiol, estrone
and ethynylestradiol showed significant binding to the beta-estradiol imprinted polymer, whereas most unrelated chemicals
did not bind. The biological receptor was activated by several estrogen-like chemicals, and to a lesser extent by some structurally
related chemicals 相似文献
17.
Ma X Zhu T Xu H Li G Zheng J Liu A Zhang J Du H 《Analytical and bioanalytical chemistry》2008,390(4):1133-1137
A chemical prototype sensor was constructed based on nanofiber-structured TiO2 and highly sensitive quartz resonators. The gas-sensing behavior of this new sensor to selected simulant warfare agents was
investigated at room temperature. Results showed rapid response and good reversibility of this sensor when used with high-purity
nitrogen. This provides a simple approach to preparation of materials needed as chemical sensors for selected organic volatiles
or warfare agents.
Figure Sensing behavior of TiO2 nanofiber sensor to chemical vapors 相似文献
18.
Synthetic materials capable of recognizing proteins are important in separation, biosensors and biomaterials. In this study,
bovine serum albumin-imprinted soft-wet polyacrylamide gel beads were prepared via inverse-phase suspension polymerization,
using acrylamide and N,N′-methylene diacrylamide as polymeric matrix components and methacrylic acid as functional monomer. The adsorption study showed,
through the imprinting process, that the imprinted gel beads had much higher adsorption capacity than the nonimprinted gel
beads, and that the matching of the surface zeta-potential between the templates and the imprinted gel beads can enhance the
imprinting effect. Adsorption kinetics indicated that the adsorption process could be described as an apparent first-order
kinetic process for the gel beads. From the adsorption isotherm curve, we found that the adsorption of the imprinted gel beads
was in agreement with the Langmuir adsorption model. Moreover, selectivity testing of the imprinted gel beads showed that
imprinted gel beads exhibited good recognition for BSA as compared to the control protein. We speculate that the formation
of complementary shapes and multiple-point electrostatic interactions between the imprinting cavities and the template proteins
are the two factors that lead to the imprinting effect.
相似文献
19.
Urisu T Asano T Zhang Z Uno H Tero R Junkyu H Hiroko I Arima Y Iwata H Shibasaki K Tominaga M 《Analytical and bioanalytical chemistry》2008,391(8):2703-2709
A new planar-type ion channel biosensor with the function of cell culture has been fabricated using silicon on an insulator
substrate as the sensor chip material. Coating of the sensor chip with fibronectin was essentially important for cell incubation
on the chip. Although the seal resistance was quite low (∼7 MΩ) compared with the pipette patch-clamp gigaohm seal, the whole-cell
channel current of the transient receptor potential vanilloid type 1 (TRPV1) channel expressing HEK293 cells was successfully
observed, with a good signal-to-noise ratio, using capsaicin as a ligand molecule.
Figure A new planer type ion channel biosensor with function of cell culture is fabricated using the silicon on insulator substrate
as the sensor chip material. The coating of the sensor chip by the fibronectin was essentially important for the cell incubation
on the chip. Whole cell channel current of TRPV1 channel was successfully observed using capsaicin as a ligand molecule with
good signal to noise. 相似文献
20.
Moslem Mansour Lakouraj Masoud Mokhtary 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):53-56
Abstract A Mild and efficient method for preparing amides by reaction of nitriles with benzhydrol and tertiary alcohols is described
using polyvinylpolypyrrolidone-supported boron trifluoride. Selective amidation of benzhydrol in the presence of primary benzyl
alcohols was also achieved.
Graphical abstract
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