更昔洛韦在单壁碳纳米管修饰电极上的电化学行为

运用循环伏安法研究了更昔洛韦在单壁碳纳米管修饰电极上的电化学行为,提出了一种简便、准确、灵敏的检测药物更昔洛韦的电化学分析方法．在pH 4．0的0．04 M B-R（磷酸＋冰醋酸＋硼酸）缓冲溶液中,更昔洛韦在单壁碳纳米管修饰电极上于1．08 V电位处有一峰形很好的氧化峰．与裸玻碳电极相比,更昔洛韦在单壁碳纳米管修饰电极上的电位负移了近30 mV,峰电流增加了近15倍,表明该修饰电极对更昔洛韦有较强的电催化作用．在最佳的试验条件下,氧化峰电流与更昔洛韦在3．5×10-7～1．2×10-5 M浓度范围内呈良好线性关系,检出限为1．8×10-8 M．该方法可用于药剂中更昔洛韦的分析．     

碳糊修饰电极测定抗坏血酸的研究及应用

在1.0 mool/L KCl的介质中,采用邻苯二甲酸二正辛酯修饰碳糊电极测定抗坏血酸(AA),抗坏血酸的浓度在9.1×10-6-3.4×10-3mol/L范围内与峰电流呈线性关系,相关系数r=0.9994,检测限5.7×10-6mol/L,并且探讨了电极过程的特性.测定了市售抗坏血酸片和橙汁中抗坏血酸的含量,结果满意.     

碳糊电极吸附伏安法测定痕量锑

根据锑与溴邻苯三酚红(BPR)生成的络合物在碳糊电极上的吸附特性, 建立了测定痕量锑的吸附伏安法. 整个分析过程分3个步骤: 吸附富集、还原和溶出. 用单因素变化法得出最佳试验条件为: 以含40 μmol/L BPR的0.10mol/L HCl为富集底液; 富集时间150 s; 还原和溶出介质为0.20mol/L HCl; 还原电位为-0.50V; 还原时间为60 s;扫描范围为-0.5～0.20V. 考察了共存离子的影响. 二次导数溶出峰电流与锑(Ⅲ)浓度在1. 0nmol/L～0. 50μmol/L范围内呈良好的线性关系, 检出限达0.5nmol/L. 该方法已成功应用于人发和水样中锑的测定.     

Electrochemical behaviors of lomefloxacin at a single-wall carbon nanotube-modified electrode and its interaction with bovine serum albumin

The electrochemical behaviors of lomefloxacin at a single-wall carbon nanotube-modified glassy carbon electrode have been investigated by cyclic voltammetry. In a Britton-Robinson buffer (pH 4. 5 ), lomefioxacin yields a sensitive and well-defined oxidation peak at ca. 1.24 V (vs. SCE) on the modified electrode. Compared with the bare glassy carbon electrode, the oxidation peak current of lomefloxacin significantly increases and the oxidation peak potential positively shifts. Under the optimal conditions, the interaction of lomefloxacin with bovine serum albumin is also investigated. The results indicate that an electrochemically inactive supramolecular complex is formed and the formation of complex between lomefloxacin and bovine serum albumin is an intercalation mechanism. The proposed methods offer a reference for the studies on the biological effects and action mechanism of lomefioxacin with albumins in vivo.     

芦丁在碳糊电极上的电化学行为

文章研究了芦丁在碳糊电极上的电化学行为.实验结果表明,芦丁在碳糊电极上的电极过程为一受扩散控制的两电子、两质子参与的准可逆过程.芦丁的氧化峰电流与芦丁浓度的平方根在1-100 mg/L范围内呈良好的线性关系.将该方法用于芦丁片中芦丁含量测定,结果满意.     

槲皮素在碳纳米管修饰碳糊电极上的电化学行为及测定

本文研究了槲皮素在多壁碳纳米管修饰碳糊电极上的电化学行为.实验结果表明:槲皮素在多壁碳纳米管修饰碳糊电极上的电极过程为一受吸附控制的两电子、两质子参与的准可逆过程,电子传递系数α=0.53.槲皮素的氧化峰电流与槲皮素浓度在1.0×10-7～6.0×10-3mol/L范围内呈良好的线性关系,可应用于槐花米中槲皮素含量测定.     

Electrochemical detection of hydrogen peroxide at a waxed graphite electrode modified with platinum-decorated carbon nanotubes

Platinum-decorated carbon nanotubes(CNT-Pt) were produced by the chemical reduction method. A novel modified electrode was fabricated by intercalated CNT-Pt in the surface of waxed graphite,which provided excellent electrocatalytic activity and selectivity for both oxidation and reduction of hydrogen peroxide. The current response of the modified electrode for hydrogen peroxide was very rapid and the detection limits in amperometry are 2.5×10-6 mol/L at reduction potential and 4.8×10-6 mol/L at oxidation po...     

Effect of carbon, silicon, and manganese content on mean flow stress at elevated temperature

Ten studied steels including different carbon content, silicon content, and manganese content were deformed in compression over a temperature range of 600 C to 1 000 C at the strain rate of 1 s1. The curves of the mean flow stress-deformation temperature were drawn up. The mean flow stresses of higher carbon content steels decreased continuously as the applied deformation temperature increased in the whole temperature range, while the mean flow stress of lowest carbon steel displayed an abrupt drop near the two phases region. The reason for the abrupt drop phenomena was explained as the result of phase transformation. The mean flow stresses of steels with high silicon content and low manganese content also have this phenomena.