银盘电极盐酸柔红霉素电化学行为及其与BSA的相互作用

应用线性扫描伏安法和循环伏安法研究盐酸柔红霉素在银盘电极上的电化学行为及其与牛血清白蛋白(BSA)的相互作用.结果表明,在pH6.50的Britton-Robinson缓冲溶液中,盐酸柔红霉素有一灵敏的还原峰,峰电位Ep-0.64V(vs.SCE),缓冲液加入BSA后盐酸柔红霉素的还原峰峰电流下降,据此建立了BSA的电化学测定方法.在优化条件下,峰电流与BSA浓度于1.0×10-8～1.0×10-4mol·L-1(r=0.9965)范围内呈线性关系,检出限为5.0×10-9mol·L-1.同时还测定了盐酸柔红霉素与BSA的结合比和结合常数.     

盐酸阿霉素在玻碳电极上的电化学行为研究及分析应用

采用线性扫描伏安法和循环伏安法研究了盐酸阿霉素在玻碳电极上的电化学行为及电极反应机理,优化了测定盐酸阿霉素的各实验参数。结果表明,在0.01 mol/L的HCl溶液中,盐酸阿霉素在-0.40 V处出现(vs.SCE)一灵敏的还原峰,峰电流与其溶液浓度在5.0×10-8~1.0×10-6mol/L(r=0.999)和1.0×10-6~1.0×10-5mol/L(r=0.998)范围内呈良好的线性关系,检出限为1.0×10-8mol/L。并用循环伏安法研究了盐酸阿霉素的峰电流性质,发现电极反应属于准可逆过程,出现一对灵敏的氧化还原峰,体系属准可逆吸附波。利用盐酸阿霉素在玻碳电极的电化学行为建立的分析方法可用于盐酸阿霉素的质量监控及药代动力学研究。     

石墨烯修饰玻碳电极用于循环伏安法测定盐酸表阿霉素

将石墨烯修饰在玻碳电极表面用于循环伏安法测定盐酸表阿霉素。在pH 4.0的B-R缓冲溶液中,在修饰电极上,盐酸表阿霉素在-0.382V处可见明显的氧化峰,且氧化峰电流比在裸玻碳电极上提高两倍以上。盐酸表阿霉素的氧化峰电流与其浓度在1.0×10-7~1.0×10-6 mol·L-1范围内呈线性关系,检出限(3S/N)为2.0×10-9 mol·L-1。方法用于盐酸表阿霉素注射液的测定,加标回收率在95.9%~97.7%之间,测定值的相对标准偏差(n=6)小于2%。     

血红蛋白在月桂酸修饰玻碳电极的电催化行为

研究血红蛋白在月桂酸修饰电极上的电化学行为,在0.02mol.L-1KH2PO4-Na2HPO4(pH=7)的缓冲液中,+0.6～-0.7V(vs.Ag/AgCl)电位范围内,Hb于该修饰电极产生不可逆还原电流峰.还原峰电流ip与v1/2呈线性关系,ip随溶液pH值和血红蛋白浓度的增加而增大,其浓度在1.00×10-8～5.00×10-9mol.L-1和1.92×10-6～2.06×10-7mol.L-1范围内分段呈线性变化关系.实验数据经进一步分析拟合,得到更精确的信息.该电极可作为检测血红蛋白的新型电化学生物传感器.     

大黄酚和牛血清蛋白相互作用的电化学/光谱性质研究

在pH=4.0的Britton-Robinson(B-R)缓冲体系中,应用循环伏安法、示差脉冲伏安法和紫外光谱法对大黄酚与牛血清白蛋白(BSA)相互作用的电化学/光谱性质进行研究.结果表明,二者结合生成了一种非电活性的超分子化合物.BSA的存在导致大黄酚氧化还原峰电流降低,峰电位基本不变,峰电流的下降值同所加入的BSA浓度在一定范围内呈线性关系.线性范围为5.0×10-6~1.0×10-7mol/L,检出限为3×10-7mol/L.     

酸性橙Ⅱ与牛血清白蛋白相互作用的电化学研究

以电化学法和光度法对酸性橙Ⅱ(AOⅡ)与牛血清白蛋白(BSA)的相互作用进行了研究。在pH 7.20的Tris-HCl缓冲溶液中,AOⅡ有一灵敏的还原峰,峰电位Ep约为-0.69 V(vs.SCE),加入BSA后AOⅡ还原峰电位正移,峰电流下降,据此建立了一种测定BSA的电分析方法。在优化条件下,峰电流下降值与BSA的浓度在5.0×10-8~1.0×10-5mol/L(r=0.9900~0.9939)范围内呈良好的线性关系,检出限为3.0×10-8mol/L。测定了AOⅡ与BSA的结合比和结合常数,并对结合反应机理进行了初步的探讨。     

秋水仙碱与牛血清白蛋白相互作用的电化学研究

以电化学方法对秋水仙碱与牛血清白蛋白的相互作用进行了研究。在0.3 mol/L H2SO4底液中,秋水仙碱在玻碳电极上产生一不可逆的氧化峰,峰电位为1.18 V(vs.SCE),加入表面活性剂四丁基氯化铵后,秋水仙碱的峰信号得到明显提高。在上述条件下,加入BSA后秋水仙碱的氧化峰电位正移,峰电流下降,峰电流下降值与BSA加入的浓度在1.5×10-7～2×10-6mol/L(r=0.9978)范围内有良好的线性关系,检出限达4.0×10-8mol/L。进一步探讨了秋水仙碱与BSA的结合数和结合常数,得到结合数为1,结合常数为2.40×105L/mol。     

盐酸异丙嗪的微波增敏方波伏安法测定

以玻碳电极作工作电极,在微波作用下用循环伏安法和方波伏安法研究了盐酸异丙嗪的电化学特性,结果表明微波可以增大峰电流,并应用于盐酸异丙嗪的检测,建立了一种新的检测盐酸异丙嗪的电化学方法.在最佳实验条件下,无微波作用时用方波伏安法检测盐酸异丙嗪,其响应电流与盐酸异丙嗪的浓度在4.0×10-6 ～1.0×10-4 mol/L范围呈线性关系(r=0.998 2,n=7),线性回归方程为I(A)=0.040 3c(mol/L)+5.0×10-7,检出限为4.0×10-7 mol/L;在微波作用下用方波伏安法检测盐酸异丙嗪,其响应电流与盐酸异丙嗪的浓度在4.0×10-6 ～1.0×10-4 mol/L范围有很好的线性关系(r=0.999 1,n=7),线性回归方程为I(A)=0.045 7c(mol/L)+6.0×10-7,检出限为2.0×10-7 mol/L.在4.0×10-6 ～1.0×10-4 mol/L范围微波增敏的峰电流与无微波条件下峰电流的比值平均值为1.22.该方法用于盐酸异丙嗪片的测定,结果满意.     

Study on the Interaction of T(4-Mop)PS4 with BSA

以四-(4-甲氧基-3-磺酸基苯)卟啉(T(4-Mop)PS4)为探针,通过T(4-Mop) PS4与牛血清白蛋白(BSA)的相互作用,建立了测定BSA的电化学分析方法.T(4-Mop)PS4的峰电流变化(AIp)与BSA在2.0×10-6～ 1.0×10-5mol·L-1范围内呈良好的线性关系,检出限为1.2×10-6mol· L-1;对5.0×10-6mol·L-1BSA平行测定8次,其相对标准偏差为2.0％,回收率为95％～104％.组氨酸、缬氨酸、苯丙氨酸、丝氨酸、异白氨酸、谷氨酰胺、苏氨酸等氨基酸对BSA的测定不产生干扰.采用紫外可见光度法、荧光光谱法和线性扫描伏安法( LSV)研究了T(4-Mop) PS4与BSA之间的相互作用,并测定了二者相互作用的结合常数和结合比.研究表明,T(4-Mop)PS4与BSA之间主要以疏水作用力结合,形成了1:1的稳定复合物.     

多巴胺在镍(Ⅱ)与水杨醛谷氨酸配合物修饰的碳黑微电极上的电化学行为

制备了水杨醛谷氨酸合镍修饰碳黑微电极,在JP-303极谱分析仪上研究了多巴胺(DA)在该修饰电极上的电化学行为,试验结果表明,在pH 7.0的磷酸盐缓冲介质中,多巴胺在该修饰电极上其峰电流增强达3倍之多.产生一灵敏的氧化峰,在0.14 V处峰电流与DA浓度在2.0×10-7～1.0×10-3mol L-1范围内呈线性关系,检出限(3σ)为1.0×10-7mol·.L-1,应用于盐酸多巴胺注射剂中多巴胺的测定,测定结果的RSD(n=7)值小于3.5%,回收率为96%～103%.     

微透析取样-流动注射电化学检测测定表柔比星与牛血清白蛋白体外结合参数

建立了微透析取样-流动注射电化学检测法测定表柔比星与牛血清白蛋白体外结合参数的方法。流动相为pH 3.0的0.1 mol/L H3PO4-NaH2PO4缓冲液(含3.4×10﹣5mol/L Na2EDTA),流速为0.3 mL/min。电化学检测的工作电极为玻碳电极,工作电位为0.52V。表柔比星浓度在5.0×10-5～5.0×10-7 mol/L范围内与峰电流呈良好的线性关系,其相关系数为0.9997,检出限为2.0×10-7mol/L。结合微透析取样,实现了对表柔比星与牛血清白蛋白结合参数的测定。表柔比星与牛血清白蛋白的体外结合符合Scatchard曲线,结合常数和结合位点数分别为2.41×104L/mol和4.02。     

甲氧氯普胺的测定及与牛血清白蛋白相互作用的研究

建立了多壁碳纳米管糊电极测定盐酸甲氧氯普胺(MCPM)的电化学分析方法,研究了MCPM与牛血清白蛋白(BSA)相互作用的电化学行为。在pH2.2的Britton-Robinson(B-R)缓冲溶液中,MCPM在1.084V处出现一灵敏的氧化峰。电化学测定MCPM的线性范围为0.17～10.3mg/L,检出限为0.03 mg/L。对5.18mg/L的MCPM进行11次平行测定,相对标准偏差为2.4%。当BSA加入到MCPM溶液中,MCPM的氧化峰电流明显降低。其降低值(ΔIp)与BSA的浓度在5.00×10-7～1.67×10-5mol/L范围内呈良好线性关系,检出限为2.0×10-7mol/L。MCPM与BSA相互作用的结合常数为1.05×105L/mol。     

Fluorescence Spectrometric Study on the Interactions of Terazosin Hydrochloride and Prazosin Hydrochloride with Bovine Serum Albumin Using Warfarin and Diazepam as Site Markers

Abstract

The binding interaction of the terazosin hydrochloride and prazosin hydrochloride with bovine serum albumin (BSA) was studied by spectrofluorimetry. Both of these two compounds quenched the fluorescence of BSA. The thermodynamic parameters (ΔH ⁰, ΔS ⁰ and ΔG ⁰) obtained from the fluorescence data measured at two different temperatures showed that the binding of terazosin hydrochloride to BSA involved hydrogen bonds and that of prazosin hydrochloride to BSA involved hydrophobic and electrostatic interactions. In this work, the competitive interaction of the terazosin hydrochloride and prazosin hydrochloride with BSA was studied by three-way excitation-emission fluorescence with the aid of parallel factor analysis (PARAFAC).     

阿托伐他汀钙与牛血清白蛋白的相互作用

采用电化学方法并结合紫外、红外光谱分析, 研究了近生理pH 实验条件下新型抗血脂紊乱药物阿托伐他汀钙(AC)与牛血清白蛋白(BSA)的相互作用, 探讨了BSA对AC峰电流的增敏和减敏效应. 实验发现, 在pH为7.17的NaH₂PO₄-Na₂HPO₄缓冲溶液中, AC在静汞电极上产生一个还原峰, 加入BSA后峰电位发生移动且峰电流发生变化. 电化学研究结果表明, 部分疏水性AC小分子的芳香基团通过疏水作用镶嵌到BSA疏水微区内部, 使AC与BSA之间通过疏水作用力形成一种1:1的结合物, 结合常数为1.67×10⁵. 紫外吸收光谱结果表明,AC的加入使BSA的紫外吸收峰发生红移且有减色效应, 导致BSA 构象改变、α-螺旋含量减小. 红外光谱结果显示, AC与BSA分子中氨基酸残基的硫及氮原子形成键合作用.     

Electrochemical Investigation of Calcium Dobesilate and Interactions with Bovine Serum Albumin on Gold Nanoparticle–Modified Glassy Carbon Electrode

Abstract

The electrochemical behavior of calcium dobesilate (CD) and its interaction with bovine serum albumin (BSA) have been investigated, and the stoichiometric coefficient and association constant between CD and BSA were obtained. It was found that gold nanoparticles have a strong electrocatalytic effect on CD. With the addition of BSA in CD solution, both the oxidation and reduction currents decreased, but the peak potentials stayed almost unchanged. Non-electrochemical-active supramolecular complex BSA-CD_m was formed via the reaction of CD with BSA. This makes it feasible for CD to be used as an electrochemical probe for determining the concentration of BSA.     

Electrochemical studies of the interaction of tetraphenylporphyrin tetrasulfonate (TPPS) with albumin

An electrochemical investigation of the interaction of TPPS with BSA on a Hg electrode is reported for the first time. The addition of BSA to TPPS solution results in a decrease of both the reduction and the oxidation current with no change of the peak potentials. In presence of BSA, no new peaks appear, and the standard rate constant k _s is not significantly changed. The reaction of TPPS with BSA yields a kind of supramolecular complex TPPS-BSA, which is electrochemically non-active. The equilibrium constant for the complex has been calculated. The decrease of the peak current can be used to determine BSA concentrations. Received: 2 August 1998 / Revised: 21 September 1998 / Accepted: 24 September 1998     

Electrochemical studies of the interaction of tetraphenylporphyrin tetrasulfonate (TPPS) with albumin

An electrochemical investigation of the interaction of TPPS with BSA on a Hg electrode is reported for the first time. The addition of BSA to TPPS solution results in a decrease of both the reduction and the oxidation current with no change of the peak potentials. In presence of BSA, no new peaks appear, and the standard rate constant k _s is not significantly changed. The reaction of TPPS with BSA yields a kind of supramolecular complex TPPS-BSA, which is electrochemically non-active. The equilibrium constant for the complex has been calculated. The decrease of the peak current can be used to determine BSA concentrations. Received: 2 August 1998 / Revised: 21 September 1998 / Accepted: 24 September 1998     

Linear sweep voltammetric determination of protein based on its interaction with Alizarin Red S

In this paper, the electrochemical behavior of the interaction of Alizarin Red S (ARS) with bovine serum albumin (BSA) was investigated on the hanging mercury drop electrode (HMDE). In the acidic solution (pH 4.2), ARS can be easily reduced on the HMDE and it has a well-defined polarographic wave at −0.29 V (SCE). On addition of BSA or human serum albumin (HAS) into the ARS solution, the reduction peak current of ARS decreases without the movement of the peak potential and the appearance of new peaks. The study shows that a new electrochemically non-active complex is formed via intercalation of ARS with BSA or HSA, which can not be reduced on the Hg electrode. The decrease of reductive peak current of ARS is proportional to BSA and HSA concentration in the range of 2.0–60 and 2.0–40 mg l⁻¹, respectively. The detection limit of BSA and HSA is 1.0-mg l⁻¹. The analytical results of human serum and urine samples by this method were in good agreement with the Coomassie brilliant blue G-250 assay. The binding number and the binding interaction mechanism are also discussed.     

Niosomes vs microemulsions: new carriers for topical delivery of Capsaicin

Simple, sensitive and rapid adsorptive voltammetric behaviour of drotaverine hydrochloride onto the HMDE has been explored and validated in surfactant media by using cyclic, differential pulse and square-wave voltammetry. Addition of Tween-20 to the drotaverine hydrochloride containing electrolyte enhances the reduction current signal. The voltammograms of the drug with Tween-20 in phosphate buffers of pH 2.5-11.0 exhibit a single well defined reduction peak which may be due to the reduction of -CC- group. The cyclic voltammetric studies indicated the reduction of drotaverine hydrochloride at the electrode surface through two electron irreversible step and diffusion-controlled. The peak current showed a linear dependence with the drug concentration over the range 0.8-7.2μgmL(-1). The calculated LOD and LOQ are 1.8 and 6.0ngmL(-1) by SWCAdSV and 8.1 and 27.2ngmL(-1) by DPCAdSV, respectively. The procedure was applied to the assay of the drug in tablet form with mean percentage recoveries of 100.2% with SWCAdSV and 99.7% with DPCAdSV. The validity of the proposed methods was further assessed by applying a standard addition technique.