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核黄素在玻碳电极上的电化学行为 总被引:8,自引:0,他引:8
用电位扫描、旋转环盘电极和微分电容等方法研究了核黄素在玻碳电极上的电化学行为。在pH〈6的介质中,观察到一个典型的氧化还原波,它是可逆的二电子反应,其还原产物RFH2在电极上的吸附为弱吸附,溶出性能良好,在6〈pH〈10的介质中,出现两个分离但仍有部分重叠的氧化还原波,相应于两步单电子反应,还原所生成的RFH和RFH2发生吸附,很难溶出。在pH〉10的介质中,仍然出现两个分离但有部分重叠的氧化还原 相似文献
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以抗坏血酸为还原剂,采用微波水热法化学还原氧化石墨烯合成了石墨烯纳米片,制备了石墨烯修饰的玻碳电极(RGO/GCE),并采用循环伏安法、计时电量法、交流阻抗法等电化学技术研究了尿酸在该修饰电极上的电化学行为及其影响因素。结果表明,在PBS缓冲溶液中,尿酸(UA)在石墨烯修饰电极上的电极反应是一个受扩散控制的不可逆氧化过程。电极反应的转移电子数n=2,有效面积A=0.182 cm2,扩散系数D=1.51×10-6 cm2.s-1。UA的氧化峰电流与其浓度在5.0×10-6~1.5×10-4 mol/L范围内呈良好线性,r=0.995 7。利用该RGO/GCE修饰电极可以快速准确地测定UA,检出限为2.7×10-7 mol/L,加标回收率为98%~100%。 相似文献
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采用一步电化学共还原的方法将纳米金(AuNPs)、Nafion、电化学还原石墨烯(ERGO)修饰到玻碳电极(GCE)表面,制成修饰电极AuNPs/Nafion/ERGO/GCE。以扫描电镜对其进行表征,用循环伏安法和微分脉冲伏安法研究对苯二酚在该修饰电极上的电催化行为。优化了实验参数,对苯二酚在2.0~100μmol/L及100~800μmol/L浓度范围内与其氧化峰电流呈良好的线性关系,检出限为0.3μmol/L。用该修饰电极成功地进行了实际水样中对苯二酚含量的测定。 相似文献
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以部分电化学还原的氧化石墨烯(pErGO)修饰的玻碳电极(GCE)作为工作电极(pErGO/GCE),用于苦参碱(MT)含量的电化学测定.在活化好的GCE上滴涂氧化石墨烯(GO),用恒电位法在-0.75 V下还原GCE表面的GO 200 s,得到的电极即为pErGO/GCE.以0.1 mol·L-1 NaH2 PO4-... 相似文献
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以双功能化试剂鞣酸一步还原法制备了鞣酸功能化的石墨烯纳米材料(TA-G)。鞣酸不仅起到还原剂的作用,还用作功能化试剂包裹石墨烯纳米片。将所制备的TA-G用于构建芦丁电化学传感器,可实现电化学信号放大并获得较好的检测灵敏度。电极反应动力学结果表明,芦丁在该修饰电极的电化学行为受表面准可逆过程控制。优化后的实验条件为p H 3.0,TA-G(1.0μg/m L)的电极修饰量为8μL,扫速为100m V/s,富集圈数为100圈。在优化条件下,芦丁的还原峰电流在1.0×10-8~1.0×10-5mol·L-1浓度范围内呈现良好的线性关系,检出限(S/N=3)为6.0×10-9mol/L。该传感器具有较高的稳定性、选择性和特异性,可实现实际样品中芦丁的灵敏检测,从而拓宽了石墨烯的应用领域并为药物的快速检测提供了新思路。 相似文献
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利用石墨烯/DNA/纳米金(Gr/DNA/GNPs)修饰电极对布洛芬(IB)的电化学行为进行了研究。分别采用紫外-可见分光光度法和扫描电镜成像技术对Gr/DNA/GNPs复合材料进行了表征。比较了不同修饰电极的检测效果并考察了缓冲体系及修饰量等对测定的影响。实验结果表明,IB在Gr/DNA/GNPs复合材料修饰电极上的电化学信号较为明显,在0.1 mol·L-1PBS缓冲溶液(pH 6.8)中,IB于0.83 V处可观察到1个灵敏的氧化峰。在最佳实验条件下对IB进行检测,其线性范围为7.2×10-7~4.9×10-5mol·L-1,检出限为1.5×10-7mol·L-1。干扰实验和重复实验的结果表明,该修饰电极选择性及重现性良好。用于实际样品的检测,结果满意。 相似文献
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《Electroanalysis》2002,14(24):1728-1732
An electrochemical study related to the electrooxidation of 4‐amino‐3‐thio‐5‐methyl‐1,2,4‐triazole (I), 4‐amino‐3‐thio‐5‐phenyl‐1,2,4‐triazole (II) and 3‐thio‐5‐phenyl‐1,2,4‐triazole (III), in 10% v/v methanol‐acetate buffer pH 4.6 has been performed. A variety of electrochemical techniques such as differential pulse voltammetry, cyclic voltammetry, double‐potential step chronoamperometry, rotating‐disk electrode voltammetry and coulometry, were employed to clarify that the mechanism of the electrode process follows the oxidation of thiol compounds. All the compounds exhibit similar redox behavior under the given conditions. They display one irreversible oxidation peak, which is diffusion controlled. From the plot of current function in cyclic voltammetry and the ratio of ic/ia less than one in double‐potential step chronoamperometry, it was established that these compounds undergo an one electron oxidation followed by a dimerization process involving the formation of disulfide derivative (EC mechanism). The pKa values were obtained by the dependence of limiting current and potential with in the wide pH interval. The transfer coefficients, the diffusion coefficients and rate constant of coupled chemical reaction were also reported. The substituent effects were also investigated. 相似文献
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在HAc-NaAc底液中,卡可西灵在汞电极上有两个还原峰,第一峰峰电位Epc1=0.04V(vs.Ag/AgCl),为2电子转移的可逆过程;第二峰峰电位Epc2=-0.39V,为4电子转移的不可逆过程,第二峰具有明显的吸附性。本文探讨了该吸附特性,认为吸附型体为中性分子,属于不可逆吸附体系。测得其电极反应动力学参数αnα和卡可西灵在汞电极上的饱和吸附量,估计了每个卡可西灵分子所占的面积,建立了测定 相似文献
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QIAN Yong-gui SUN Zi-jie HU Jing-bo ** LU Yi-qiang LI Qi-long . Department of Chemistry Beijing Normal University Beijing P. R. China . Department of Chemistry Beijing University of Science Technology Beijing P. R. China 《高等学校化学研究》2004,20(1):103-107
In a 0.02 mol/L Na2HPO4-KH2PO4(PBS) buffer solution(pH=6.82), the electrochemical behavior of mitoxantrone was studied by linear-sweep voltammetry and cyclic voltammetry at a Pt/C ion implantation modified microelectrode. A sensitive reduction peak was observed. The peak potential was -0.72 V(vs.SCE), the peak current was proportional to the concentration of mitoxantrone within the ranges of 7.0×10-8-9.0×10-7 mol/L and 1.0×10-6-2.4×10-5 mol/L, with a detection limit of 4.0×10-8 mol/L. The linear correlation coefficients were 0.9994 and 0.9992, respectively. This method has been applied to the direct determination of mitoxantrone in simulated urine. The recoveries were in the range from 96.2% to 105.9%. The reduction process was a quasi-reversible one with adsorptive characteristics at the Pt/C microelectrode. The electrode reaction rate constant ks and the electron transfer coefficient α of the system were determined to be 4.5 and 0.65 s-1, respectively. The experiments showed that Pt element had surely been implanted into the surface of the carbon fiber, and the atomic Pt improved the electrocatalytic activity. The Pt/C microelectrode had a good stability and reproducibility. 相似文献
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Arockiajawahar Anancia Grace Sukumar Thillaiarasi Venkataraman Dharuman 《Electroanalysis》2021,33(4):993-1006
Tungsten oxide (W) decorated titanium oxide (T) adsorbed onto a graphene (Gr) and modified the glassy carbon electrode for the electrochemical quantification of riboflavin (RF) in edible food and pharmaceuticals. For comparison, nanocomposites are formed using graphene oxide (GO), reduced graphene oxide (rGO) and pure graphite (G) sheets to study the electrochemical activities towards riboflavin. The ternary WTGr modified GCE shows the highest electrocatalytic activity due to synergetic interactions between the metal oxide and graphene. The electrochemical observations are supported by the SEM, HRTEM, XRD, UV-Vis, Zeta potential (ζ) and size data. The sensor shows a wide linear range 20 nM–2.5 μM with a detection limit 25.24 nM and sensitivity (4.249×10−8 A/nM). The fabricated sensor is validated in real samples. 相似文献
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香兰素在玻碳电极上的电化学行为及其循环伏安测定 总被引:1,自引:0,他引:1
在pH 7.5的Tris-HCl缓冲介质的底液中,在循环伏安图上在峰电位+0.54 V处可见到香兰素的灵敏的氧化峰.其峰电流Ip与香兰素的浓度在3.286×10-6~3.944×10-4mol·L-1范围内呈线性关系,检出限(3S/N)为1.643×10-6mol·L-1.据此提出了循环伏安测定香兰素的方法,并应用于测定巧克力中香兰素的含量.在巧克力试样中加入不同浓度的香兰素标准,按方法测定以求测定方法的回收率,研究了香兰素在玻碳电极上的电化学行为,结果表明:香兰素的电极过程具有吸附性和不可逆性. 相似文献
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奥美拉唑的示波极谱法测定及其电化学行为 总被引:5,自引:1,他引:4
在 0 .1 mol/L NH3- NH4 Cl( p H 8.90 )底液中 ,奥美拉唑在汞电极上有一灵敏的导数还原峰 ,峰电位 Ep=- 1 .1 0 5 V ( vs.SCE) ,峰高与奥美拉唑的浓度在 5 .0×1 0 - 7~ 1 .0× 1 0 - 5范围内呈线性关系 ( r=0 .9989) ,检出限为 2 .0× 1 0 - 7mol/L。该法应用于胶囊中奥美拉唑含量的测定 ,结果满意。对奥美拉唑在汞电极上的电化学行为进行了探讨 相似文献
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吡柔比星在钴离子注入修饰微电极上电化学行为及其应用 总被引:4,自引:0,他引:4
吡柔比星在0.1mol/LHAc-NaAc(pH=5.05)缓冲溶液中,用Co离子注入修饰碳纤维微电极进行研究,得到一良好的还原峰,峰电位Ep=-0.520V(vs.SCE).峰电流与吡柔比星浓度在1.0×10-7~6.0×10-6mol/L范围内成线性关系,检出限为5.0×10-8mol/L.用于病人尿样测定,回收率在91.6%~106.7%之间.吡柔比星的还原为可逆吸附过程,伴随着两个电子、两个氢离子参加电极反应.用扫描电子显微镜(SEM)和俄歇电子能谱(AES)两种表面分析技术对Co离子注入修饰微电极的表面状况、表面元素组成及深度分布进行测定.实验表明,Co离子确实被注入到碳纤维表面上.扫速对催化效率的影响实验证明体系存在催化作用. 相似文献