共查询到19条相似文献,搜索用时 478 毫秒
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将氯过氧化物酶(CPO)与双十二烷基二甲基溴化铵(DDAB)混合后滴涂于玻碳(GC)电极表面, 制得CPO-DDAB/GC修饰电极. 循环伏安结果显示, 固定在电极表面的CPO可与电极之间发生直接的电子传递作用. 利用高效液相色谱-质谱联用技术对反应产物进行表征, 结果显示, 以该CPO修饰电极为工作电极, 在氧气饱和的氯化钾-岩白菜素溶液中, 利用CPO催化氧还原生成的过氧化氢可进一步驱动CPO对岩白菜素的催化氯化反应. 经估算总转化数(TTN)达到13600, 即1 mol CPO可催化13600 mol岩白菜素. 相似文献
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将氯过氧化物酶(Chloroperoxidase,CPO)与双十二烷基溴化铵(DDAB)形成的类生物膜滴涂到Nation修饰的玻碳电极表面,再滴涂壳聚糖制得Chi/CPO-DDA B/Nafion/GC修饰电极.循环伏安曲线上可以观察到一对可逆的氧化还原电流峰,表明CPO与电极之间发生了直接的电子传递.该修饰电极可有效地催化O2还原为H2O2,产生的H2O2作为氧源与电极上的CPO结合进一步催化氧化肉桂醇,产物经气质联用色谱、以及红外光谱测试鉴定为肉桂醛,总的肉桂醛转化量达到80500mol/mol CPO,为高效专一获得末端醛提供了一种绿色合成方法.此外,还讨论了壳聚糖对提高修饰电极稳定性的作用. 相似文献
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对氯酚在碳纳米管修饰玻碳电极上的电化学行为研究 总被引:1,自引:0,他引:1
研究了对氯酚在多壁碳纳米管修饰玻碳电极(MWNTs/GC)上的电化学行为。MWNTs/GC电极对对氯酚具有良好的电催化作用,相比玻碳电极对氯酚的氧化峰电位负移76 mV,峰电流达到玻碳电极上的8倍。通过线性扫描伏安法研究了富集时间、溶液pH和扫描速率对对氯酚氧化的影响。并采用计时电流法研究了氧化峰电流与对氯酚的浓度关系,结果显示峰电流与对氯酚的浓度在2.0×10^-7-2.0×10^-4mol/L范围内呈良好线性关系,检出限为8.8×10-8mol/L(S/N=3)。放置7 d后,对氯酚在碳纳米管上的峰电流仍能达到最初电流的96.2%,表明电极的稳定性较好。 相似文献
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基于多壁碳纳米管/壳聚糖多层膜修饰玻碳电极邻苯二酚的测定 总被引:1,自引:0,他引:1
改进了碳纳米管在壳聚糖溶液中的分散方法,制备了多壁碳纳米管/壳聚糖多层膜修饰玻碳电极,对比了不同修饰层数膜电极的循环伏安和电化学阻抗行为,5层多壁碳纳米管/壳聚糖膜修饰玻碳电极的电化学性能优良.在最优实验条件下,该修饰玻碳电极对邻苯二酚(CAT)有灵敏的响应,CAT浓度在3.99×10-6~9.09×10-4mol/L范围内与氧化峰电流呈良好的线性关系,检出限为2.39×10-6mol/L(S/N=3).该修饰玻碳电极性能稳定,测定4×10-5mol/LCAT溶液,RSD(n=10)为2.1%;15周后,该电极的响应值仅降低1.9%. 相似文献
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用循环伏安法制备了银掺杂聚L-甲硫氨酸修饰玻碳电极,研究了对苯二酚和邻苯二酚在该修饰电极上的电化学行为,建立了同时测定对苯二酚和邻苯二酚的新方法.研究发现,在pH=5.0的磷酸盐缓冲溶液中,扫速为100 mV/s时,对苯二酚和邻苯二酚在银掺杂聚L-甲硫氨酸修饰玻碳电极上均出现1对氧化还原峰,峰电位分别为:Epa=0.228 V、Epc =0.162 V和Epa=0.347 V、Epc =0.287 V,二者的氧化峰电位差达119 mV,还原峰差达125 mV.在最佳的条件下,用差分脉冲伏安法同时测定邻苯二酚和对苯二酚的线性范围为3.00 ×10-6~1.00 ×10-4mol/L,检出限为8.0×10-7 mol/L(对苯二酚)和5.0×10-7 mol/L(邻苯二酚).此法用于废水样中对苯二酚和邻苯二酚的测定,获得满意结果. 相似文献
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银掺杂聚L-天冬氨酸修饰电极的制备及对肾上腺素的测定 总被引:1,自引:0,他引:1
利用循环伏安法,研究了银和L-天冬氨酸在玻碳电极表面电化学聚合的条件,制备了银掺杂聚L-天冬氨酸修饰电极。研究了肾上腺素在修饰电极上的电化学行为,建立了循环伏安法测定肾上腺素的新方法。在pH=3.5的磷酸盐缓冲溶液中,扫描速率为50mV/s时,肾上腺素在修饰电极上产生一对明显的氧化还原峰,峰电位分别为Epa=0.447V,Epc=0.387V。用循环伏安法测定时,氧化峰电流与肾上腺素浓度分别在8.00×10-8~1.00×10-5mol/L和1.00×10-5~1.00×10-4mol/L范围内呈良好的线性关系,检出限为8.0×10-9mol/L。 相似文献
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The direct electrochemistry of xanthine oxidase (XOD) was accomplished at a gold electrode modified with single-wall carbon nanotubes (SWNTs). A pair of well-defined redox peaks was obtained for XOD with the reduction peak potential at -0.478 V and a peak potential separation of 28 mV at pH 7.0. Both FT-IR spectra and the dependence of the reduction peak current on the scan rate revealed that XOD adsorbed onto the SWNT surfaces. The redox wave corresponds to the redox center of the flavin adenine dinucleotide (FAD) of the XOD adsorbate. Compared to other types of carbonaceous electrode materials, the electron transfer rate of XOD redox reaction was greatly enhanced at the SWNT-modified electrode. The peak potential was shown to be pH dependent. Spectral methods verified that the attachment of XOD onto SWNTs does not perturb the XOD conformations drastically. 相似文献
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A film of single-wall carbon nanotubes (SWNTs) and didodecyldimethylammonium bromide (DDAB) is prepared by casting a solution
of SWNTs and DDAB onto the surface of a gold electrode. The electrochemical behavior of the film is investigated by electrochemical
impedance spectroscopy and cyclic voltammetry. In a 0.10 M phosphate buffer solution of pH 7.0, the film-modified electrode
gives a pair of redox peaks in cyclic voltamograms, with the anodic and cathodic peak potentials of 0.095 and 0.042 V. The
peak currents change linearly with the scan rate at 30–500 mV/s. The modified electrode has an excellent electrocatalytic
activity towards the oxidation of ascorbic acid (AA). The catalysis currents are proportional to the AA concentration in the
range of 5.0 × 10−4 to 3.2 × 10−2 M. The linear-regression equation is i (μA) = 1.2079 + 1.3987 × 103
c
AA (M), with a correlation coefficient of 0.9995. The detection limit is 2.2 × 10−4 M (signal-to-noise ratio of 3). The Michaelis-Menten constant (K
m) is 1.0 × 10−4 M by the Lineweaver-Burk equation.
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From Elektrokhimiya, Vol. 41, No. 10, 2005, pp. 1193–1199.
Original English Text Copyright ? 2005 by Cheng, Jin, Zhang.
The text was submitted by the authors in English. 相似文献
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A room-temperature ionic liquid N-butylpyridinium hexafluorophosphate was used as a binder to construct an ionic liquid modified carbon paste electrode, which
was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. The ionic liquid carbon paste
electrode (IL-CPE) showed enhanced electrochemical response and strong analytical activity towards the electrochemical oxidation
of dopamine (DA). A pair of well-defined quasireversible redox peaks of DA appeared, with the redox peaks located at 215 mV
(E
pa) and 151 mV (E
pc) (vs. the saturated calomel electrode, SCE) in pH 6.0 phosphate buffer solution. The formal potential (E
0′) was calculated as 183 mV (vs. SCE) and the peak-to-peak separation as 64 mV. The electrochemical behavior of DA on the IL-CPE
was carefully investigated. Under the optimal conditions, the anodic peak currents increased linearly with the concentration
of DA in the range 1.0 × 10−6–8.0 × 10−4 mol/L and the detection limit was calculated as 7.0 × 10−7 mol/L (3σ). The interferences of foreign substances were investigated and the proposed method was successfully applied to the determination
of DA injection samples. The IL-CPE fabricated was sensitive, selective and showed good ability to distinguish the coexisting
ascorbic acid and uric acid. 相似文献