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81.
82.
本文用自制的单一或复合的微生物传感器作检测器,与高效液相色谱结合,对7种氮基酸,5种有机醇,以及同化糖与醇,维生素等7种混合体系进行分离硷测,取得较好的结果。 相似文献
83.
An optical oxygen-sensing material based on the fluorescence intensity changes of pyrene-1-butyric acid (PBA) chemisorption film has been developed and characterised. The fluorescence intensity of PBA film decreased with increase of oxygen concentration. The I0/I100 value of PBA film is estimated to be 6.14±0.15 and large Stern-Volmer constant (KSV=0.028±0.13 Torr−1) is obtained. After irradiation for 24 h with 150 W tungsten lamp, little changes of oxygen-sensing properties were observed. These results indicate that PBA film is highly oxygen-sensitive and photostability device. The response times of the PBA chemisorption film were 10.0 s for switching from argon to oxygen, and 53.0 s for switching from oxygen to argon. Moreover, the optical sensor based on the PBA chemisorption film was applied to the measurement of oxygen concentration in aqueous solution. 相似文献
84.
《Electroanalysis》2003,15(14):1204-1211
Two types of glassy carbon (GC) powder (i.e., Sigradur K and Sigradur G) have been mixed with mineral oil to obtain glassy carbon paste electrodes (GCPE's). The electrochemical behavior of such electrodes at different percentages of glassy carbon has been evaluated with respect to the electrochemistry of ferricyanide as revealed with cyclic voltammetry and the best paste composition was chosen. GC was then modified with Prussian Blue (PB), mixed at different percentages with unmodified GC and with a fixed amount of mineral oil in order to obtain PB modified glassy carbon paste electrodes (PB‐GCPE's). PB‐GCPE's with different percentages of GC modified with PB (PB‐GC) were compared and the dependence on the amount of PB on their performances was evaluated by studying the parameters of cyclic voltammetry (i.e., current peak, ΔEp, anodic and cathodic current ratio, charge density) and the amperometric response to H2O2. Data interpretation based on the GC surface area is presented. GCPE's with a selected amount of PB‐GC were then tested as H2O2 probes and all the analytical parameters together with the dependence on pH were evaluated. Some preliminary experiments with these electrodes assembled as glucose, lysine and lactate biosensors are also reported. 相似文献
85.
Summary The retention, selectivity and elution order of fluorescent 1,N6-etheno derivatives of diadenosine polyphosphates and their enzymatic degradation products on octadecyl and phenyl-bonded
silica columns have been studied as a function of mobile phase pH, ionic strength and organic modifier content. Good separations
of the compounds of interest were achieved using mobile phases of around 0.1M potassium phosphate buffers at neutral pH containing
approximately 10% methanol or 4% acetonitrile for C18 columns and 5% methanol or 1.5% acetonitrile for phenyl columns. The data obtained were used to establish isocratic assays
for diadenosine polyphosphate cleaving activities from chromaffin cells using Di(1,N6-ethenoadenosine) polyphosphates as fluorogenic substrate analogues followed by fluorescence detection. 相似文献
86.
Lawrence W Dick Jr. 《Analytica chimica acta》2004,511(2):197-205
The synthesis and the spectroscopic and potentiometric characterization of electropolymerized films obtained from neutral red (NR) on Pt surface are described. FT Raman and NMR spectroscopy were used for evaluation of the resulting poly(NR) layers. Then potentiometry was applied to study the characteristics of the complexation of carboxylates with the poly(NR) films. A potentiometric poly(NR) sensor showing high selectivity for citrate anion was employed for its determination in soft drinks. 相似文献
87.
采用了研磨后超声和离心分离方法制备了二硫化钼纳米片,通过原子力显微镜(AFM)和扫描电子显微镜(SEM)对不同离心速度分离的二硫化钼纳米片进行了表征。使用循环伏安法(CV)和差分脉冲伏安法(DPV)在磺胺甲恶唑溶液中对二硫化钼纳米片修饰的玻碳电极进行了电化学行为研究。结果显示,磺胺甲恶唑在二硫化钼修饰电极的循环伏安图上有一对氧化还原峰。其峰电流值与扫描速度的平方根成正比,是扩散控制过程。DPV扫描结果显示,磺胺甲恶唑的峰电流与其浓度之间存在着明显的线性关系。研磨超声方法制备出的二硫化钼纳米片层材料在电极上能够加速电子的转移和传输,从而有效提高峰电流值,为进一步研制准确测定磺胺甲恶唑电化学传感器提供了一种可选择的材料和电化学分析方法。 相似文献
88.
An anionic sensor based on Reichardt’s betaine is described here. The dye is blue-green in chloroform but becomes colorless under protonation. Increasing amounts of different anions were added into the solution of the protonated dye. The addition of F− and caused the reappearance of the original blue-green color, while the addition of I− made the solution of the protonated dye yellow. The observations are discussed based on the fact that F− and can act as bases accepting a proton from the protonated dye and also in relation to the formation of a complex between the protonated dye and iodide. 相似文献
89.
A solid state copper(II) ion sensor is reported based on the application of electropolymerized undoped (neutral) polycarbazole
(PCz) and polyindole (PIn) modified electrodes. The new sensor shows high selectivity to Cu2+ ions with a detection limit of 10–5 M. PCz and PIn are formed respectively by the anodic oxidation of 50 mM carbazole and 5 mM indole monomers in dichloromethane
containing 0.1 M tetrabutylammonium perchlorate on a platinum electrode using a single compartment cell. Potentiostatic polymerization
of both the monomers are carried out at 1.3 V and 1.0 V vs. Ag/AgCl, respectively. Perchlorate ions were electrochemically
removed from the polymer films by applying – 0.2 V vs. Ag/AgCl. Polymer-coated electrodes are incubated in 1 M KCl solution
for 8 h followed by incubation in distilled water for 2 h before using as a metal ion sensor. The undoped PCz and PIn electrodes
were found to be highly selective and sensitive for Cu2+ ions with little selectivity for Pb2+ and negligible response towards Ag+, Hg2+, Cu+, Ni2+, Co2+, Fe2+, Fe3+ or Zn2+. Potentiometric responses for Cu2+ ions are recorded for both the sensor electrodes together with a double-junction Ag/AgCl reference electrode. Calibration
curves for Cu2+ are reported for both ion sensors. The polymer-modified electrodes were found to be stable for several weeks.
Electronic Publication 相似文献
90.