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ABSTRACT: BACKGROUND: Acrylamide has attracted worldwide concern due to its neurotoxicity, genotoxicity, reproductive-development toxicity. It is necessary to develop an accurate and reliable analytical method to prevent the harm on the human health. RESULTS: In this study, a sensitive and fast analytical method of direct competitive biomimetic enzyme-linked immunosorbent assay (BELISA) was developed using a hydrophilic imprinted membrane as biomimetic antibody. This novel imprinted membrane was directly synthesized on the well surface of MaxiSorp polystyrene 96-well plate in aqueous environment, and it exhibited high binding ability and specificity toward acrylamide. Under the optimal conditions, the established BELISA method had a good sensitivity (IC50 , 8.0 ± 0.4 mg L(-1) ) and a low limit of detection (IC15 , 85.0 ± 4.2 µg L(-1) ). The blank potato samples spiked with acrylamide at three levels of 100, 250 and 500 µg L(-1) were extracted and determinate by the proposed method, and good recoveries ranging from 90.0% to 110.5% were obtained. This presented method was applied to the quantitative detection of the acrylamide in French fries and cracker samples. Also, the results were correlated well with that obtained by the gas chromatography method. CONCLUSION: With good properties of high sensitivity, simple pre-treatment and low cost, this BELISA could be a promising screening method in food sample analysis.
Journal of the Science of Food and Agriculture 04/2013; · 1.44 Impact Factor
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ABSTRACT: BACKGROUND: Garlic (Allium sativum L.) bulb is processed into various forms such as crushed garlic, garlic juice, granules, dehydrated garlic pieces and garlic powder. However, greening is often a major problem when garlic is crushed, since it affects the appearance and quality of the resulting product. Therefore study of the formation mechanism of garlic green pigments is very important for garlic processing. RESULTS: The effect of porphobilinogen (PBG) on the formation of garlic green pigments was investigated in this study. As the storage time increased, there was a significant positive correlation between garlic greening and PBG content at low temperature (4 °C). PBG content decreased significantly during the garlic greening process. When treated with respiration inhibitor, both garlic greening strength and PBG content decreased as the concentration of respiration inhibitor increased. The green colour was generated when extracted PBG and allicin mixed thoroughly. CONCLUSION: There was a clear relationship between PBG content and garlic greening. As a provider of pyrrolyl compounds, PBG plays an important role in the formation of garlic green pigments. © 2013 Society of Chemical Industry.
Journal of the Science of Food and Agriculture 01/2013; · 1.44 Impact Factor
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ABSTRACT: In this study, a new way to substitute the biology antibody was introduced by using a hydrophilic molecularly imprinted film, which was directly prepared on the well surface of MaxiSorp polystyrene 96-well plate by the bulk polymerization technique. This imprinted film exhibited good recognition and fast adsorption-desorption dynamics toward olaquindox. Using it as the recognition element, a fast and new direct competitive biomimetic enzyme-linked immunosorbent assay (BELISA) method for the determination of olaquindox in chick feed was developed. This BELISA method had low cross-reactivities of 6.2% and 12% for two analogues. Under the optimal conditions, the sensitivity (IC50) and the limit of detection (IC15) were 700 ± 60 µg L(-1) and 17.0 ± 1.6 µg L(-1), respectively. The blank chick feed samples spiked with olaquindox at three levels were determined by this developed method with recoveries ranging from 82.0-96.0%.
Journal of Immunoassay and Immunochemistry 01/2013; 34(1):16-29. · 0.69 Impact Factor
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ABSTRACT: How to determine the multipesticide residues in vegetables is an important problem. In this study, a new molecularly imprinted polymer was synthesized using O,O-dimethyl thiophosphoryl chloride, an intermediate for the manufacture of organophosphorous pesticides, as the template. Characterization test indicated that the synthesized polymer exhibited good recognition and selectivity for dichlorvos, methamidophos, acephate, folimat, monocrotophos, parathion-methyl, phosphamidon, and malathion. A molecularly imprinted SPE coupled to GC for simultaneous separation and determination of eight organophosphorous pesticides residues was developed. Under optimal conditions, the linear range of this method was 0.001-10.0 mg/L. The LOD of this method was in the range of 0.13-0.90 μg/kg. With a flow rate of 2.5 mL/min for loading 100 mL, the enrichment factor in the range of 25-480 for the eight organophosphorous pesticides was obtained. The RSD of the eight organophosphorous pesticides based on five replicates was from 1.50 to 4.09%. The accuracy of the proposed method was evaluated by recovery measurements on spiked samples, and good recovery rates ranging from 80.11 to 97.70% were achieved. Moreover, this method was evaluated for the quantitative detection of eight organophosphorous pesticide residues in leek and pakchoi samples.
Journal of Separation Science 12/2012; 35(24):3501-8. · 2.73 Impact Factor
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ABSTRACT: Olaquindox, as one of the antimicrobial growth accelerants, is usually used in livestock production to improve feed efficiency. Due to health concerns over possible carcinogenic, mutagenic and photoallergenic effects of olaquindox on animals, the development of simple, rapid and sensitive analytical method for determination of olaquindox is crucial and necessary.
In this study, a surface molecularly imprinted polymer was prepared by a molecular imprinting technique in combination with a sol-gel process using activated silica gel as a support material. This imprinted material exhibited with good recognition and selective ability, and fast adsorption-desorption dynamics toward olaquindox. Using it as the recognition element, a new on-line molecularly imprinted solid phase extraction coupled with chemiluminescence sensor for the determination of olaquindox was developed. The factors affecting preconcentration of the analytes and sensitivity of the method were all investigated. Under the optimal condition, the linear range of the calibration graph was between 2 × 10(-8) and 1 × 10(-6) g mL(-1) , and the detection limit of this method was 7 × 10(-9) g mL(-1) . The blank chick feed samples spiked with olaquindox at 0.3, 0.9 and 1.5 µg g(-1) levels were extracted and determined by this presented method with recoveries ranging from 87% to 94%. This method was validated by high-performance liquid chromatography and the results correlated well with those obtained by both methods. Moreover, this method was quantitatively analysed with two contaminated chick feed samples.
This study will provide a sensitive and fast method for the monitoring of olaquindox residues in foods. Copyright © 2012 Society of Chemical Industry.
Journal of the Science of Food and Agriculture 04/2012; 92(13):2696-702. · 1.44 Impact Factor
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ABSTRACT: This study reports a new online molecularly imprinted solid phase extraction coupled to chemiluminescence for the determination of trichlorfon. This molecularly imprinted polymer (MIP) was prepared through bulk polymerization, in which methacrylic acid (MAA) was used as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. This novel functionalized material was characterized by FT-IR spectra and adsorption, and it exhibited good recognition and selective ability and fast adsorption-desorption dynamics toward trichlorfon. The factors affecting preconcentration of the analytes and sensitivity of the method are discussed in detail. Under the optimal condition, the linear range of the calibration graph was between 0.02 and 1.0 ng L(-1), and the detection limit was 1 × 10(3) ng L(-1). The blank cucumber samples spiked with trichlorfon at three levels were extracted and determined by the presented method with recoveries ranging from 83.5 to 94.5%, and the results were correlated well with those obtained using gas chromatography. Moreover, this developed method was successfully applied to the quantitative detection of trichlorfon residues in leek samples.
Journal of Agricultural and Food Chemistry 11/2011; 59(24):12745-51. · 2.82 Impact Factor
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ABSTRACT: Olaquindox, one of the antimicrobial growth accelerants, is usually used as a feed additive in livestock production to improve feed efficiency. Due to health concerns over possible carcinogenic, mutagenic and photoallergenic effects of olaquindox on animals, the development of a simple, rapid and sensitive analytical method for determination of olaquindox is crucial and necessary.
In this paper, a novel and hydrophilic functionalised material of olaquindox-imprinted polymer was synthesised in aqueous solution by a surface molecular imprinting in combination with a sol-gel process. This imprinted material was characterised by Fourier transform infrared, scanning electron microscopy, and static and kinetic adsorption experiments, and results showed that it had good recognition and selective ability, and fast adsorption-desorption dynamics for olaquindox. Applying the prepared material as sorbent, a method of molecularly imprinted solid-phase extraction (MISPE) for separation and analysis of olaquindox residues in feeds coupled with HPLC was presented. Under the selected MISPE condition, the detection limit (S/N = 3) for olaquindox was 68.0 ng L(-1), the RSD for five replicate extractions of 50 µg L(-1) olaquindox was 9.8%. The blank chick feed samples spiked with olaquindox at 0.0025 and 0.010 mg g(-1) levels were extracted and determined by the developed method, with recoveries ranging from 90% to 96%.
This method was applied for enrichment and analysis of olaquindox in animal feed samples with good accuracy and repeatability. This study will provide a sensitive and fast method for the monitoring of olaquindox residues in foods.
Journal of the Science of Food and Agriculture 06/2011; 91(13):2378-85. · 1.44 Impact Factor
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ABSTRACT: In this paper, a new separation sorbent of magnetic chitosan microsphere was prepared by means of suspension process using magnetic-Fe(3)O(4) nanoparticles as magnetic material and glutaraldehyde as the cross-linker. The morphology and properties of magnetic chitosan microspheres were characterized by FT-IR, SEM and adsorption test, and the results showed that they had good recognition, high selective ability and fast adsorption-desorption dynamics for estriol (E3), 17β-estradiol (E2) and diethylstilbestrol (DES). Applying this material as SPE sorbent, a method for separation, enrichment and analysis of estrogens in samples coupled with HPLC was developed. Under the optimized condition, the detection limit (S/N=3) for three estrogens was 3.2-20.1 ng/L, and the RSD for five replicate extractions of 50 μg/L E3, E2 and DES was 4.6-8.3%. The blank river water spiked with E3, E2 and DES at 0.05 and 0.2 mg/L levels were extracted and determined by the developed method with good recoveries ranging from 85.5 to 103.7%.
Journal of Separation Science 01/2011; 34(1):46-52. · 2.73 Impact Factor
