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An amperometric biosensor for the determination of l-lysine based on l-lysine-α-oxidase immobilized by co-crosslinking on a platinum electrode previously modified by an overoxidized polypyrrole film is described. The optimization of experimental parameters, such as pH and flow rate, permitted to minimize significantly substrate interferences even using a low specific, commercial enzyme. The relevant biases introduced in the measurement of lysine were just about 1% for l-arginine, l-histidine and l-ornithine, roughly 4% for l-phenylalanine and l-tyrosine. The developed approach allowed linear lysine responses from 0.02 mM up to 2 mM with a sensitivity of 41 nA/(mM × mm2) and a detection limit of 4 μM (S/N = 3). No appreciable loss in lysine sensitivity was observed up to about 40 days. Allowing polypyrrole layer to remove interference from electroactive compounds, the present method revealed suitable to detect l-lysine in a pharmaceutical and cheese sample, showing a good agreement with the expected values. 相似文献
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The three-dimensional morphology has sufficient interface contact and can be in favor of the electronic transport process. In this work, the demand for high-performance electrodes such as energy storage devices has been designed. Polypyrrole and tungsten oxide composite materials (PPy-WO3) have been synthesized by cyclic voltammetry (CV) technology at −0.6 to 0.9 V versus saturated calomel electrode (SCE) for 20 cycles. The PPy-WO320 mV/s, PPy-WO360 mV/s, and PPy-WO3120 mV/s electrodes have been prepared by CV technology at sweep rates of 20, 60, and 120 mV/s. The influences of scan rate on morphologies and charge storage properties of the composites are discussed. Among them, a three-dimensional flake structure for PPy-WO320 mV/s with a size of up to several micrometers was synthesized. PPy-WO320 mV/s composites as electrode materials exhibit a wide charge storage potential window of 1.4 V (between −0.9 and 0.5 V vs. SCE) and a specific capacitance of 145.13 F/g at 1 mA/cm2. Moreover, the long-term stability of PPy-WO320 mV/s and PPy has been investigated in 5 M LiCl aqueous electrolyte. The stability of the materials can be improved by inorganic and organic composites. 相似文献
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光热治疗是近年来兴起的一种治疗方法,具有靶向性强、适应性广的特点。在光热治疗中,通过光热剂对光的吸收将光能转化为热能,从而实现治疗作用,因而光热剂的光热转化性能直接决定了光热治疗的效果。光热剂的种类丰富,涵盖由无机到有机等组成和性能各异的多种材料。其中,聚吡咯具备良好的生物相容性、优异的光稳定性以及光热转化性能,在光热治疗领域受到广泛关注,是一种拥有巨大应用潜力的光热剂,然而其在光热治疗领域的发展趋势及前景却鲜有报道。本文综述了聚吡咯及其纳米复合材料的制备方法,详述了聚吡咯及其纳米复合材料在光热治疗领域中的应用情况,包括聚吡咯基纳米材料的自身性能和实际光热治疗的效果,指出以聚吡咯为基体或修饰材料来制备具有CT、磁共振、光声显影及光热治疗性能的聚吡咯基复合材料已成为发展趋势。在此基础上,本文还总结了聚吡咯基纳米复合材料在制备和应用中存在的问题,并分析了其在发展过程中遇到的挑战以及在生物医学应用中的前景。 相似文献
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Xiaoling Yang Yiduo Mi Fang Liu Jing Li Haixiang Gao Sanbing Zhang Wenfeng Zhou Runhua Lu 《Journal of separation science》2020,43(12):2419-2428
In this work, a novel extraction technique based on the effervescence‐assisted dispersion and magnetic recovery of attapulgite/polypyrrole sorbents was developed for determining the concentrations of five pyrethroids in honey samples. The magnetic nanoparticles were synthesized by a one‐pot method. Several experimental parameters that affected the extraction efficiency, including the dispersion conditions, pH, ionic strength, and desorption conditions, were investigated. Under optimal conditions, the calibration curves for the five pyrethroids in honey samples exhibited good linearity, with r2 values ranging from 0.9979 to 0.9990. The limits of detection varied between 0.21 and 0.34 µg/L. Satisfactory recoveries of 81.42–106.73% with intra‐ and interday relative standard deviations of less than 6.94 and 10.89%, respectively, were obtained. Moreover, the sorbents exhibited acceptable batch‐to‐batch repeatability in the range of 5.06–15.01%, and each sorbent could be reused for up to four extraction cycles without a significant loss in the extraction recovery. 相似文献
26.
Elnaz Iranmanesh Moslem Jahani Azizollah Nezhadali Maliheh Mojarrab 《Journal of separation science》2020,43(6):1164-1172
This paper describes the synthesis of a molecularly imprinted polymer by chemical oxidation of pyrrole as the functional monomer, and at the presence of guaifenesin as the template. The prepared polymer was used as adsorbent in molecularly imprinted solid‐phase extraction followed by spectrophotometric determination. Different parameters in the solid‐phase extraction including sample pH, adsorbent weight, washing solution, and elution solvent were studied to determine optimum conditions for isolation and enrichment of guaifenesin. The results showed guaifenesin was quantitatively adsorbed on the molecularly imprinted polymer at pH 6.0 and completely eluted with an ethanol–water solution (50% v/v). An enrichment factor of four with satisfactory recoveries (87.0–95.0%) was obtained. The solid‐phase extraction columns could be used for up to six consecutive elution‐loading cycles without significant decreases in the analyte recoveries. The method had a dynamic range of 3.0 × 10?6–1.5 × 10?4 mol/L with a limit of detection and limit of quantification of 1.4×10?6 and 4.5×10?6 mol/L, respectively. The proposed procedure was used for the extraction and determination of guaifenesin in different pharmaceutical formulations, with satisfying results being achieved. 相似文献
27.
The electrochemical polymerization technique has been successfully applied to produce conducting polymer film of controlled ion exchange properties. Polypyrrole films were prepared by electro-oxidative polymerization with doping some alkylsulfonates or Nafion. The ion exchange characteristics across polypyrrole films were examined by means of a novel electrochemical technique, namely, the in situ electrochemical quartz crystal microbalance (EQCM) method. According to EQCM measurements, exchanging ion species was found to be successfully controlled by changing the hydrophilic–hydrophobic balance of the incorporated sulfonated-based dopants. The film's characteristics became anion- to cation-exchanging as the dopants became more hydrophobic in nature. The polypyrrole–Nafion(poly(perfluoroethylene sulfonate)) composite film became to be a complete cation exchanger. 相似文献
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在研究DNA与儿茶酚胺类分子之间相互作用的基础上, 以碳纤维电极(CFE)为基底, 制备了一种新型的DNA-过氧化聚吡咯(PPyox)生物复合膜传感器, 与单一的DNA或PPyox修饰层相比具有更高的灵敏度和选择性. 相似文献