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961.
利用分子印迹传感器选择性测定绿麦隆 总被引:3,自引:0,他引:3
以绿麦隆为模板分子,邻氨基酚为功能单体,在金电极表面电聚合制得具有特异性识别孔穴的绿麦隆分子印迹膜。采用循环伏安、差分脉冲伏安法研究了印迹膜的性能、结构、分子印迹效应和模板分析物,并比较了传感器对其它结构相似化合物的选择性响应,发现该传感器对绿麦隆检测具有良好的选择性。绿麦隆浓度在3.0×10-7~1.5×10-6mol/L范围内与峰电流呈线性关系,检出限为1.0×10-7mol/L,在干扰物质共存情况下的回收率为105%~116%。 相似文献
962.
检测维生素C的囊泡荧光传感器的制备 总被引:1,自引:0,他引:1
利用合成的含有识别基团苯硼酸和荧光读出基团萘的新型双亲化合物(DNMPBA)在THF/水选择性溶剂中自组织成囊泡,囊泡的相变温度为56.8℃;当向囊泡体系加维生素C时,DNMPBA囊泡中的萘生色基在345nm的荧光峰强度急剧减弱.荧光强度减弱归于所形成的硼酸酯增强了DNMPBA双亲化合物中一个氧原子孤对电子对萘生色基的淬灭作用.DNMPBA囊泡与维生素C的相互作用而导致体系荧光强度变化,使该体系有可能应用于检测生物物质如维生素C的化学传感器. 相似文献
963.
In this paper, a new electrochemical sensor, based on modified silver nanoparticles, was fabricated using one-step electrodeposition approach. The para-sulfonatocalix[6]arene-modified silver nanoparticles coated on glassy carbon electrode (pSC6-Ag NPs/GCE) was characterized by attenuated total reflection IR spectroscopy (ATR-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), etc. The pSC6 as the host are highly efficient to capture organophosphates (OPs), which dramatically facilitates the enrichment of nitroaromatic OPs onto the electrochemical sensor surface. The combination of the host-guest supramolecular structure and the excellent electrochemical catalytic activities of the pSC6-Ag NPs/GCE provides a fast, simple, and sensitive electrochemical method for detecting nitroaromatic OPs. In this work, methyl parathion (MP) was used as a nitroaromatic OP model for testing the proposed sensor. In comparison with Ag NPs-modified electrode, the cathodic peak current of MP was amplified significantly. Differential pulse voltammetry was used for the simultaneous determination of MP. Under optimum conditions, the current increased linearly with the increasing concentration of MP in the range of 0.01-80 μM, with a detection limit of 4.0 nM (S/N = 3). The fabrication reproducibility and stability of the sensor is better than that of enzyme-based electrodes. The possible underlying mechanism is discussed. 相似文献
964.
α-Fe2O3 nanoparticles prepared using a simple solution-combusting method have been dispersed in chitosan (CH) solution to fabricate nanocomposite film on glass carbon electrode (GCE). The as-prepared α-Fe2O3 nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM). The nanocomposite film exhibits high electrocatalytic oxidation for nitric oxide (NO) and reduction for hydrogen peroxide (H2O2). The electrocatalytic oxidation peak is observed at +0.82 V (vs. Ag/AgCl) and controlled by diffusion process. The electrocatalytic reduction peak is observed at −0.45 V (vs. Ag/AgCl) and controlled by diffusion process. This α-Fe2O3-CH/GCE nanocomposite bioelectrode has response time of 5 s, linearity as 5.0 × 10−7 to 15.0 × 10−6 M of NO with a detection limit of 8.0 × 10−8 M and a sensitivity of −283.6 μA/mM. This α-Fe2O3-CH/GCE nanocomposite bioelectrode was further utilized in detection of H2O2 with a detection limit of 4.0 × 10−7 M, linearity as 1.0 × 10−6 to 44.0 × 10−6 M and with a sensitivity of 21.62 μA/mM. The shelf life of this bioelectrode is about 6 weeks under room temperature conditions. 相似文献
965.
Cátia I.C. Esteves 《Tetrahedron》2010,66(38):7479-560
A series of emissive N-tert-butyloxycarbonyl benzyl ester asparagines bearing benzothiazole and benzimidazole units at the side chain, functionalised with electron donor or acceptor groups, were evaluated as novel amino acid based fluorimetric chemosensors for transition metal cations, such as Cu2+, Zn2+, Co2+ and Ni2+. Selective removal of the protecting groups at the N- and C-terminals was carried out in order to assess the influence of the presence of blocking groups on the overall coordination ability. The results indicate that there is a strong interaction through the donor N, O and S atoms at the side chain of the various asparagines, with high selectivity towards Cu2+ in a 1:1 complex stoichiometry. Association constants and detection limits for Cu2+ were calculated. The photophysical and metal ion sensing properties of these asparagines suggest that they can be suitable for incorporation into peptidic chemosensor frameworks. 相似文献
966.
M. Rajeswara Rao 《Tetrahedron》2010,66(9):1728-1162
3,5-Bis(trimethylsilylethynyl)-4,4-difluoro-8-(4-tolyl)-4-bora-3a,4a-diaza-s-indacene [BODIPY(CCTMS)2] has been synthesized by coupling of 3,5-dibromo-4,4-difluoro-8-(4-tolyl)-4-bora-3a,4a-diaza-s-indacene with trimethylsilylacetylene under pd(0) coupling conditions. The BODIPY(CCTMS)2 was used as a selective colourimetric and fluorescent chemodosimeter for fluoride ion, following the F− ion induced cleavage of trimethylsilyl group, the protecting group of ethyne functionality by monitoring the changes in UV-vis and fluorescence properties. The dosimeter BODIPY(CCTMS)2 display clear changes in colour, absorption and emission bands selectively for F− ion over other anions such as Cl−, Br−, I−, ClO4− and HPO42−. 相似文献
967.
Min Shao 《Tetrahedron letters》2010,51(21):2892-2895
Two anthraquinone-type π-extended tetrathiafulvalene (TTFAQ)-cored D/A triads were synthesized and characterized by UV-vis absorption and cyclic voltammetric analyses. Electronic substituent effects were unraveled by making a comparison with analogous TTFAQ derivatives previously reported. Electrochemical titrations of the two TTFAQ D/A triads with selected transition metal cations (Ag+ and Cu2+) were examined by cyclic voltammetry, and the results suggest potential application of such TTFAQ derivatives as electrochemical sensors for transition metal ions. 相似文献
968.
Motivated by the potential of electrochemical techniques to analyze hybridization events fast and in a simple and cost‐effective way we present here a detection system allowing a parallel electrochemical DNA analysis. For this purpose different probe DNA strands have been immobilized on one electrode. By the use of two different target DNA sequences, both marked with the redox active methylene blue, we can show that hybridization with the complementary probe sh“NA strands can occur without steric hindrance. Each target has been recognized down to 3nM with a very high specificity of the sensor. In addition, we can detect two different ssDNA targets labeled with different redox active molecules, methylene blue and ferrocene, on one sensor surface simultaneously. 相似文献
969.
Fabiana Gutiérrez Gabriela Ortega José Luis Cabrera María D. Rubianes Gustavo A. Rivas 《Electroanalysis》2010,22(22):2650-2657
This work reports the highly sensitive detection of quercetin using glassy carbon electrodes modified with multiwall carbon nanotubes (MWCNT) dispersed in polyethylenimine and poly(acrylic acid). The adsorptive stripping with square wave voltammetric transduction allowed the detection of 7.5 nM quercetin after 1.0 min accumulation at open circuit potential. The amperometric detection at 0.150 V is reported as an easier and simpler alternative to determine quercetin, with detection limits of 0.2 µM. The careful selection of the working conditions also made possible the detection of submicromolar levels of quercetin in the presence of excess of rutin. The proposed methodology was successfully used to quantify quercetin in onion samples. 相似文献
970.
Based on an oxygen reducing electrode combining bilirubin oxidase and multiwalled carbon nanotubes modified gold (BOD‐MWCNT‐Au electrode) a bienzyme sensor is developed. Therefore the BOD‐MWCNT‐Au electrode is covalently coupled to enzymes catalysing oxygen‐consuming reactions (glucose oxidase and ascorbate oxidase) to result in a membrane‐free bienzyme electrode. The electrochemical characterisation of these bienzyme sensors reveals an enzyme substrate sensitivity down to 250 μM glucose and 100 μM ascorbate. In addition, the assembled sensor systems allow amperometric measurements in a potential range where the influence of interfering substances reacting directly at the transducing electrode is minimised. The results indicate that the BOD electrode provides a suitable platform for sensing analytes of medical and environmental interest for which oxidases of high activity are available. 相似文献