线性扫描伏安法测定人血清白蛋白

建立了一种测定人血清白蛋白的新方法。应用线性扫描伏安法研究了灿烂甲酚蓝(BCB)与人血清白蛋白(HSA)的相互作用的条件,当BCB与HSA作用后,其峰电流下降且峰电位负移,峰电流的下降值的二阶导数(ΔI″p)同HSA的质量浓度在2.0~60.0 mg.L-1范围内呈线性关系,相关系数为0.9970。方法的检出限为2.0 mg.L-1,用于健康人血清样品的测定,回收率在95.6%~107.5%之间。     

铍试剂Ⅱ线性扫描伏安探针法测定蛋白质

铍试剂Ⅱ线性扫描伏安探针法测定蛋白质;蛋白质;铍试剂Ⅱ;线性扫描伏安法     

测定人血清白蛋白的电化学研究及分析应用

以电化学方法研究了pH 3.2的Britton-Robinson(B-R)缓冲溶液中变色酸2R与蛋白质的相互作用。变色酸2R在-0.43 V(vs.SCE)有1个良好的极谱还原峰,加入人血清白蛋白(HSA)后,其峰电位不变而峰电流下降。峰电流的下降值同HSA的浓度在(1.5~30.0)×10-8moL/L范围内呈线性关系,其线性方程为ΔIp″(nA)=-338.38+191.9c(moL.L-1),r=0.997。应用于实际人血清样品的测定,结果与经典的考马斯亮蓝G_250光度法一致。由实验结果求得人血清白蛋白和变色酸2R的结合比为1∶3,结合常数K为1.55×105。     

线性扫描伏安法研究白杨素与牛血清白蛋白的相互作用

采用线性扫描伏安法研究了白杨素与牛血清白蛋白(BSA)之间的相互作用。优化的试验条件为:①以pH 7.40的磷酸氢二钠-磷酸二氢钠缓冲溶液为介质;②反应时间为20min;③反应温度为298K;④离子强度:1.0×10-3 mol·L-1氯化钠溶液。研究发现:白杨素与BSA在相互作用后形成了一种非电活性超分子化合物,转移系数(α)为0.121 9,表观电子传递速率常数(ks)为0.914s-1。     

线性扫描极谱法测定人血清白蛋白

以线性扫描极谱法研究了在pH=6．5的Britton-Robinson缓冲溶液中灿烂甲酚蓝与人血清白蛋白的相互作用。灿烂甲酚蓝在-0．18V(vs．SCE)有一个良好的极谱还原峰,加入人血清白蛋白后,其峰电位负移而峰电流下降,峰电流的下降值同人血清白蛋白的浓度在2．0～60．0mg／L内呈线性关系,线性回归方程为Δip=18．05c 123．65,r=0．9970。     

线性扫描伏安法研究大豆甙元与牛血清白蛋白的相互作用

采用线性扫描伏安法研究了大豆甙元与牛血清白蛋白(BSA)之间的相互作用;探讨了缓冲体系、pH、反应时间、反应温度、扫描速率等对相互作用的影响.结果表明,在pH为7.4的B-R缓冲溶液中,大豆甙元与BSA在相互作用20min后形成1∶1型的单一的非电活性超分子化合物,两者的结合常数β=8.29×105 L·mol-1,转移系数α=0.367 9,表观电子传递速率常数ks为1.39s-1.     

线性扫描伏安法测定痕量铊

铊单质及其化合物是损害人体中枢神经系统的剧毒物质,其致死剂量是 740 mg[1],监测铊对环境的污染成为人们关注的问题。线性扫描伏安法(LSV)是极其有效和灵敏度高的监测铊(Ⅰ)对环境污染的方法。线性扫描伏安法测定铊(Ⅰ)的灵敏度远比原子吸收光谱法高,本法用LSV法测定铊(Ⅰ)的下限为 7×10-7 mg·L-1,比原子吸收光谱法测定铊的下限低[2]。若待测试样中含有电活性物质(如铊),用 LSV测定时会有典型的特征曲线及其峰电流(Ip)。对可逆反应 Ip=2.69×105n3/2 AD1/2υ1/2 C, 对不可逆反应Ip=2.99×105n(αna)1/2 AD1/2υ1/2 C[3],当 …     

线性扫描伏安法测定氟罗沙星

应用线性扫描伏安法和循环伏安法研究氟罗沙星在玻碳电极上的电化学行为。在含有铜离子的pH 6.5的0.10mol.L-1磷酸盐缓冲溶液中,铜离子在玻碳电极上分别于-0.136V和-0.728V处形成两个还原峰,加入氟罗沙星后铜离子的还原峰电位不变但峰电流均降低。在优化的试验条件下,于-0.136V处的峰电流降低值Δip与氟罗沙星浓度在6.40×10-7～1.5×10-4 mol.L-1范围内呈线性关系,检出限为2.10×10-7 mol.L-1。方法用于氟罗沙星片剂中氟罗沙星含量的测定,回收率在96.8%～103.5%之间。     

阶梯扫描伏安法与线性扫描伏安法相关性的理论研究——简单可逆体系

本文采用Ｒｅｉｍａｎｎ－Ｓｔｉｅｌｔｉｅｓ（黎曼－斯堤杰斯）级数展开法，指导了简单可逆电极体系的线性扫描伏安法和阶梯扫描伏安法的电流方程式，得到了能有机地统一的这两种最大为基本的伏安法的电流函数表达式，表达式简明直观，在无因次电流函数的基础详细讨论了制约阶梯扫描伏安法和线性扫描伏安法之间相关性程度的各因素，获得了一些新的结论。     

线性扫描伏安法测定丹参酮ⅡA

应用线性扫描伏安法和循环伏安法研究丹参酮ⅡA在悬汞电极上的电化学行为。在pH 3.8的0.2mol·L~（-1）乙酸-乙酸钠缓冲溶液中,丹参酮ⅡA在-0.228V（vs.Ag/AgCl）处产生一灵敏的还原峰,丹参酮ⅡA浓度在5.0×10~（-6）～2.0×10~（-5）mol·L~（-1）范围内,其线性扫描还原峰电流与...     

Adsorptive stripping voltammetric determination of netilmicin in the presence of formaldehyde

A linear sweep adsorptive stripping voltammetric method for the determination of netilmicin in the presence of formaldehyde has been proposed for the first time. In the presence of 3.0×10⁻³ g ml⁻¹ formaldehyde, netilmicin exhibits a sensitive cathodic peak at −1.30 V (vs. the saturated calomel electrode, SCE) in a medium of Britton–Robinson buffer (pH 8.7) with a scan rate of 100 mV s⁻¹ after a preconcentration period of 120 s at −1.10 V (vs. SCE). The peak current showed a linear dependence on the netilmicin concentration over the range 4.2×10⁻⁹–1.0×10⁻⁷ g ml⁻¹. The achieved limits of detection and quantitation were 1.0×10⁻¹⁰ and 3.3×10⁻¹⁰ g ml⁻¹ netilmicin, respectively. It was deduced from the experiments that the amine–aldehyde condensation product formed between netilmicin and formaldehyde is mainly responsible for the appearance of the peak. The electrochemical behavior of netilmicin in the presence of formaldehyde has been studied. The method was applied to the direct determination of netilmicin in injectable formulations and spiked human urine and serum samples.      

Determination of Sulpiride by Linear Sweep Stripping Voltammetry at a Mercury Electrode

This paper reports the electrochemical properties of sulpiride at a mercury electrode,especially its adsorptive characteristic,Sulpiride dissolved in a supporting electrolyte of a McIlvaine buffer at pH 6.8 represents a sensitive and well defined reduction wave by linear sweep stripping voltammetry.This method is based on the pre-concentration and the reduction of sulpiride at a hung mercury drop electrode.The reduction peak potential is -1.72V(vs.Ag-AgCl) and the peak current is proportional to the concentration of sulpiride in the range of 0.1-0.6 μg/mL.The detection limit is 0.0250μg/mL obtained under the experimental conditions selected in this work.The electrochemical properties of this system were investigated.and the proposed method was applied to the determination of sulpiride in pharmaceutical tablets with satisfactory results,It was compared well with the UV spectrophotometric method,showing a superior sensitivity.     

线性扫描催化伏安法的新算法

本研究利用含参数积分的导数运算，Ｒｅｉｍａｎｎ－Ｓｔｉｅｌｔｉｅｓ积分展开，推导了固态平面电极下的线性扫描平行催化伏安法的电流理论方程。所得方程直观明了，各种参数之间的关系较清晰，为无限加和形式，可以精确计算任何ｋｆ值的电流理论值，整个过程仅需个人计算机即可完成。     

Spectrophotometric assay of cephalosporins in pharmaceutical products,using chromotrope 2B and chromotrope 2R

A simple, rapid and sensitive Spectrophotometric method is proposed for the determination of cephadroxil (I), cephalexin (II) and cephradine (III). The method is based on ion-pair complex formation between these derivatives and Chromotrope 2B (C2B) or Chromotrope 2R (C2R), to give a highly coloured radical anion. The coloured products are quantified spectrophotometrically at 542 and 564 nm for C2B and C2R, respectively. The optimization of the experimental conditions is described. The method has been used for the determination of 0.4–15, 0.4–14 and 0.4–18 g/ml of drugs I, II and III, respectively. The accuracy of the method is indicated by the excellent recovery (100.0±1.7%) and the precision is supported by the low relative standard deviations 1.5%. The sensitivity of the method is discussed and the results are compared with the official method. The interference from common degradation products and excipients was also studied. The proposed method was applied successfully to the determination of the different cephalosporins in dosage forms, with good precision and accuracy. The results were compared with those given by the official B.P. 1993 method.     

A kinetic model and its parameter estimation for the process of binding copper to human serum albumin by a voltammetric method

Linear sweep anodic stripping voltammetry was applied to determine the concentration of free copper ions in the process of binding copper to human serum albumin (HSA) on the mercaptoethane sulfonate modified gold electrode surface. A kinetic model of two consecutive steps for the process of binding copper to HSA was first proposed on the basis of the electrochemical results and compared with a parallel kinetic response model by using residual analysis. The experimental data of the stripping peak currents with time was fitted according to the model and the kinetic parameters, binding rate constants, k₁ and k₂, were estimated to be 0.411 and 0.055 min^–1, respectively.     

A Linear Sweep Voltammetric Determination of DNA with Methyl Violet

A new quantitative method for the determination of DNA in aqueous solution based on the interaction of methyl violet (MV) with fsDNA by linear sweep voltammetric technique is proposed in this paper. The interaction of MV with fsDNA caused the decrease of the reductive peak current of MV at ?0.650 V (vs. SCE) on a mercury electrode in pH 1.5 Britton‐Robinson (B‐R) buffer solution. Factors including the acidity of the buffer, the reaction time, the optimal concentration of MV, the reaction temperature, the influences of the foreign substances, etc. were all carefully investigated. Under the optimal conditions, the decrease of the reductive peak current of MV was proportional to the concentration of fsDNA in the linear range of 0.90～20.0 mg/L and the detection limit for fsDNA was 0.25 mg/L with the RSD of 4.00%. Synthetic samples were determined with satisfactorily results. The stoichiometry of MV with DNA was calculated by voltammetric data and the results showed that the binding ratio of DNA:MV was 1:2 with the binding constant β as 7.36 × 10⁸.     

Square wave adsorptive stripping voltammetric determination of famotidine in urine

Electrochemical studies of famotidine were carried out using voltammetric techniques: cyclic voltammetry, linear sweep and square wave adsorptive stripping voltammetry. The dependence of the current on pH, buffer concentration, nature of the buffer, and scan rate was investigated. The best results for the determination of famotidine were obtained in MOPS buffer solution at pH 6.7. This electroanalytical procedure enabled to determine famotidine in the concentration range 1 × 10⁻⁹–4 × 10⁻⁸ mol L⁻¹ by linear sweep adsorptive stripping voltammetry (LS AdSV) and 5 × 10⁻¹⁰–6 × 10⁻⁸ mol L⁻¹ by square wave adsorptive stripping voltammetry (SW AdSV). Repeatability, precision and accuracy of the developed methods were checked. The detection and quantification limits were found to be 1.8 × 10⁻¹⁰ and 6.2 × 10⁻¹⁰ mol L⁻¹ for LS AdSV and 4.9 × 10⁻¹¹ and 1.6 × 10⁻¹⁰ mol L⁻¹ for SW AdSV, respectively. The method was applied for the determination of famotidine in urine.     

Determination of Pesticide Ethion by Linear Sweep Stripping Voltammetry

IntroductionOrganophosphorus pesticides( OPPs) are widelyused in agriculture as insecticides, but they are foundto contaminate agricultural products such as fruits andvegetables to variable extents. Because of their toxicproperties[1,2]and the potential r…     

Voltammetry determination of trace manganese with pretreatment glassy carbon electrode by linear sweep voltammetry

This paper described the determination of trace manganese using linear sweep voltammetry at a pretreatment glassy carbon electrode. The glassy carbon electrode pretreated by electrochemical method in the 0.1 mol l⁻¹ NaOH solution greatly improved the electrode responsibility in the determination of manganese(II). The barrier to the detection of low manganese concentration was overcome by means of autocatalytic effect of manganese oxide deposited on the electrode in advance. Under the optimum experiments condition (0.04 mol l⁻¹ NH₃-NH₄Cl buffer solution, pH 9.0), the linear range was 4×10⁻⁸ to 1×l0⁻⁶ mol l⁻¹ Mn(II) for linear sweep voltammetry and 1×10⁻⁹ to 4×10⁻⁸ mol l⁻¹ Mn(II) for convolution voltammetry. The relative standard deviation for 2×10⁻⁸ mol l⁻¹ Mn(II) is 3.4%. The proposed method is simple, rapid, sensitive and selective. It had been applied to the determination of trace manganese in samples with satisfactory results.