Electrochemical Studies on the Interaction of Heparin with Phenosafranine and Its Analytical Application

The interaction of phenosafranine (PSF) with a glycosaminoglycan of heparin (Hep) in aqueous solution was characterized by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) in this paper and further used for Hep detection. In pH 1.5 Britton‐Robinson (B‐R) buffer solution PSF had a well‐defined voltammetric reductive peak at ?0.256 V (vs SCE), and the electrochemical response was faded by the addition of Hep. Cyclic voltammetric experiments indicated that the electrochemical behaviors of free PSF didn't change no matter whether Hep was presented in PSF solution or not. Based on the decrease of the peak current, a second order derivative linear sweep voltammetry was used to establish a sensitive electroanalytical method for Hep. The peak current was proportional to the concentration of Hep in the range of 0.7～20.0 mg L^?1, demonstrating that this method was suitable for routine Hep detection. Under optimal conditions, the linear regression equation for the Hep determination was ΔIp”(nA) = 46.30 C (mg L^?1) + 343.31 (n = 11, γ = 0.991) with a detection limit of 0.08 mg L^?1 (3σ). The established method was further successfully applied to heparin sodium injection samples determination. The interaction mechanism was discussed based on the electrostatic attraction of the negatively charged Hep with the positively charged PSF, and the stoichiometry of Hep‐PSF was calculated by the voltammetric method.     

Spectroscopic studies on the spontaneous assembly of phenosafranin on glycosaminoglycans templates

Spectroscopic studies showed that binding of phenosafranin (PSF) molecules to glycosaminoglycans (GAGs) resulted in the following observations: (i) appearance of a 52.6 nm hypsochromic shift of the visible absorption band; (ii) static quenching of fluorescence from PSF; (iii) induction of strong circular dichroism (CD) signal of PSF. Stoichiometry of the PSF-GAGs complex was determined by spectrophotometric titration, spectrofluorimetric titration and MacIntosh extraction method. These studies demonstrated the formation of the extended helical PSF array aligned on the helical backbone of GAGs templates by electrostatic force, and the dimeric binding mode of PSF to each anionic site was proposed. The comparative studies between PSF-heparin (Hep) and PSF-chondroitin 4-sulfate (CS) complexes revealed that: (i) stoichiometry of PSF-Hep complex was 1.8 times of PSF-CS complex; (ii) Hep was more effective than CS (1.8 times) in decreasing the absorbance of PSF; and (iii) Stern-Volmer constants of the Hep-PSF system were greater than that of the CS-PSF system. These differences were attributed to the different charge density on the Hep and CS molecules, which in turn suggested that the electrostatic force was dominant in the interaction between PSF and GAGs.     

Microdetermination of double-stranded DNA by linear sweep voltammetry with phenosafranine.

A novel voltammetric method for the determination of microamounts of fish sperm double-stranded (ds) DNA based on its interaction with phenosafranine (PSF) is proposed in this paper. In a pH 3.5 Britton-Robinson (B-R) buffer solution, PSF had a well-defined second-order derivative linear-sweep voltammetric reductive peak at -0.32 V (vs. SCE) on a mercury electrode. After the addition of dsDNA into the PSF solution, the reductive peak current decreased significantly without a shift of the peak potential, and no new peak appeared. The experiment results showed that a new supramolecular complex was formed after the interaction of dsDNA with PSF, which resulted in a decrease of the diffusion coefficient, and then a decrease of the reductive peak current. The interaction conditions and the electrochemical detection conditions were carefully investigated. Under the optimal conditions, the decrease of the peak current was proportional to the dsDNA concentration in the range 1.0 - 40.0 microg/mL with the linear regression equation DeltaI(p)'(nA) = 32.59C(microg/mL) - 4.03 (n = 13, gamma = 0.998) and a detection limit of 0.25 microg/mL (3 sigma). The interaction mechanism was considered based on the aggregation of the dsDNA-PSF supramolecular complex; the stoichiometry of this supramolecular complex was calculated based on voltammetric data with a binding number of 3 and a binding constant of 2.76 x 10(12). This method was successfully applied to the determination of synthetic samples and the polymerase chain reaction (PCR) product of the nopaline synthase gene (NOS) DNA from genetically modified organisms (GMOs) with satisfactory results.     

Molecular spectroscopic studies on the interaction of glycosaminoglycans with brilliant cresol blue and its analytical application.

The interaction of brilliant cresol blue (BCB) with glycosaminoglycans (GAGs), such as heparin (Hep) and chondroitin 4-sulfate (CS), in aqueous solution has been studied by spectrophotometry and light scattering spectroscopy. Absorbance of BCB at 632 and 594 nm decreased on addition of Hep or CS with the appearance of a new blue-shifted absorption band at 550 nm, which indicated that new metachromatic complex formed. The linear decrease in absorbance of BCB at 632 nm was observed. In addition, Hep was more effective than CS (1.7 times) in decreasing absorbance of BCB. The stoichiometry of Hep or CS with BCB was determined by spectrophotometric titration and the MacIntosh extraction method. The result showed that the stoichiometry of BCB/Hep was 1.8 times that of BCB/CS. These results suggested that the interaction between GAGs and BCB was the result of electrostatic forces, and the differences between Hep and CS were attributed to the different negative charge numbers on repetitive disaccharides unit. Studies on the effects of alcohol and urea indicated that GAGs only interacted with the aggregates of BCB. Moreover, a strong light scattering signal was observed after mixing BCB with GAGs. Furthermore, the light scattering intensity at light scattering bands was proportional to the concentration of Hep or CS added when the concentration of BCB was constant.     

甲基紫与肝素钠结合反应的电化学研究及分析应用

应用电化学分析法研究了在pH 1.5的酸性反应条件下肝素钠与甲基紫的结合反应. 甲基紫在滴汞电极上有一个不可逆的还原峰, 峰电位为－0.58 V (vs. SCE), 加入肝素钠后峰电位发生正移且峰电流下降, 利用电化学方法对电极反应过程进行了研究, 结果发现两者结合后生成了一种电化学活性的复合物, 导致溶液的电化学参数发生了变化, 求解出结合比为1∶3, 结合常数为2.47×10¹⁴, 对结合反应条件和电化学检测条件进行了优化, 在最佳条件下峰电流的降低同肝素钠的浓度在0.2～4.0 mg/L范围内呈线性关系, 线性回归方程为∆I_p″ (nA)＝－724.9＋1741.4c (mg/L) (n＝11, γ＝0.994), 检测限为0.072 mg/L. 将本方法应用于肝素钠样品的测定, 结果令人满意. 对常见干扰物质的影响进行了考察, 表明本方法具有较好的选择性.     

Voltammetric determination of hyaluronic acid based on its interaction with phenosafranine

In this paper, a cationic dye of phenosafranine (PSF) was selected as a bioprobe to determine hyaluronic acid (HA) by linear sweep voltammetry on the dropping mercury working electrode (DME). In pH 4.5 Britton-Robinson (B-R) buffer solution, PSF has a well-defined second order derivative linear sweep voltammetric reductive peak at −0.42 V (vs. SCE). After the addition of HA into the PSF solution, the reductive peak current decreased apparently without the movement of reductive peak potential. Based on the decrease of the reductive peak current, a new voltammetric method for HA determination was established. The conditions for the interaction and the electrochemical detection were optimized and the interference substances for the detection were investigated. Under the optimal experimental conditions the difference of peak current was directly proportional to the concentration of HA in the range from 0.8 to 50.0 mg/l with the linear regression equation as Δip″ (nA) = 93.85 + 22.92c (mg/l) (n = 14, γ = 0.995) and the detection limit was calculated as 0.901 mg/l (3). This new method was further applied to determine the HA content in the synthetic samples with satisfactory results and good recovery. The stoichiometry of PSF-HA complexes was calculated and the binding mechanism was also discussed.     

Effects of Acetone,Ethanol, Isopropanol,and Dimethyl Sulfoxide on Amylose-Iodine Complex

ABSTRACT

The amylose-iodine (AI) complex formation was studied by absorption spectra in water and water containing varying proportions of ethanol, acetone, isopropanol and dimethyl sulfoxide (DMSO). Complex formation is most favored in pure water and decreases as the proportion of nonaqueous solvent is increased. A decrease in the absorbance intensity at around 615 nm (for AI complex) is accompanied by a peak shift towards 550 nm and an increased absorbance at around 350 nm (for unbound iodine). The amount of the nonaqueous solvent added, as well as the order in which it is added relative to amylose and iodine solution, change remarkably the extent of the AI complex formation. A mechanism of the complex formation is proposed.     

Effects of Acetone,Ethanol, Isopropanol and Dimethyl Sulfoxide on Amylose-Iodine Complex†

Abstract

The amylose-iodine (AI) complex formation was studied by absorption spectra in water and water-containing varying proportions of ethanol, acetone, isopropanol and dimethyl sulfoxide (DMSO). Complex formation is most favored in pure water and decreases as the proportion of nonaqueous solvent is increased. A decrease in the absorbance intensity at around 615 nm (for AI complex) is accompanied by a peak shift towards 550 nm and an increased absorbance at around 350 nm (for unbound iodine). The amount of the nonaqueous solvent added, as well as the order in which it is added relative to amylose and iodine solution; change remarkably the extent of the AI complex formation. A mechanism of the complex formation is proposed.

     

Synthesis of a New Cobalt (II) Complex and its Interaction with DNA

The interaction of metal complexes with DNA has been widely studied by differentmethods such as spectrophotometry, light scattering technique, fluorometry1-3. Manycomplexes such as Co(phen)2 ,Co(en)2 ,Fe(EDTA)2- etc.4,5 have been synthesized and 3+ 3+their effect on DNA has been studied in order to further explain the mechanism of genemutation, anti-cancer or cancer-induced reason and DNA targeted drugs. In this paper,a new cobalt complex was synth…     

博莱霉素与DNA在镍离子注入修饰电极上的相互作用 及其应用

博莱霉素(BLM)在0.1mol/LHOAc-NaOAc缓冲溶液(pH4.62)中,在Ni/GCE离子注入修饰电极上有一灵敏的还原峰,峰电位为-1.16V(vs.SCE),峰电流与BLM浓度有关。用线性扫描和循环伏安法研究体系的行为表明,体系为具有加速作用的不可逆过程,是注入的Ni加速BLM的还原。引入DNA后,BLM的峰电位为-1.15V(vs.SCE),与未加入DNA前几乎完全一致;只使峰电流降低,形成一种非电活性的结合物,求得该结合物的结合比为BLM：DNA=3：1,结合常数为β=3.16×10^16,用线性扫描和循环伏安法,并辅以紫外可见光谱法等手段研究表明,电极过程仍为不可逆过程,与未加入DNA时一样。加入DNA后,BLM的峰电流降低,可用于DNA的测定,回收率在96.8～103.9%之间.     

Interaction of iodine species with glycogen at high concentrations of iodine

Glycogen–iodine (GI) complex formation has been studied at different concentrations of iodine and glycogen. For each glycogen concentration (0.25, 0.125, 0.0625, 0.0313 g/L), the iodine concentration was varied from 0.0317 to 1.59 g/L and the absorbance readings were taken at 453 and 560 nm (GI wavelengths of maximum absorbance). The 453 nm absorbance curves for the GI solution (GI complex and unreacted iodine), and that of the pure iodine solution (without glycogen) level off at a high iodine concentration, and give a peak in the subtracted curve. The 560 nm curves consistently increase in absorbance, and no peak is noticed in the subtracted curve. The spectra of concentrated iodine solutions in water and alcohol suggest the formation of neutral iodine clusters. We suggest that these iodine clusters do not react with glycogen, and that the GI complex formation takes place by the addition of I₂ molecules. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 927–931, 1997     

阿托伐他汀钙与β-环糊精相互作用的研究及应用

采用线性扫描伏安法和循环伏安法并结合紫外分光光度法研究了新型抗血脂紊乱药物阿托伐他汀钙(AC)与β-环糊精(-βCD)的相互作用.探讨了-βCD对AC的峰电流及AC对-βCD吸附峰电流的影响,测得在0.06mol/LKH2PO4-Na2HPO4(pH=7.17)缓冲溶液中,AC与-βCD包结比为1:1,用电流法测得包结物的形成常数为9.09×104L/mol.根据碱性介质条件下β-CD分子与AC形成包结物而使β-CD吸附峰电流减小的特性,建立了一种利用β-CD间接测定AC的伏安方法.     

镍离子注入修饰电极上米托蒽醌与DNA相互作用的电化学研究

研究了在镍离子注入修饰电极和0.05mol/LTris-0.5mol/LNaCl缓冲溶液(pH=7.1)中,米托蒽醌(MX)与DNA作用的电化学.在37℃恒温1.5h条件下,MX与DNA形成一种非电活性的结合物,使MX峰电流降低,其结合比n(MX):n(DNA)=2:1,结合常数为1.61×10¹²,电子转移系数为0.41,电极反应速率常数0.33s^-1.加入DNA后,MX峰电流降低,据此,可以测定DNA.     

铜(Ⅱ)-三氮唑偶氮络合物与脱氧核糖核酸相互作用的电化学行为

运用电化学方法研究了铜（Ⅱ）－三氮唑偶氮（2－[2,3,5-三氮唑偶氮]-5－二甲氨基苯甲酸，TZAMB）络合物与脱氧核糖核酸（DAN）的相互作用。在pH2.5(0.05mol/L）邻苯二甲酸氢钾（PBS）缓冲溶液中，DNA与Cu(Ⅱ）－TZAMB络合物形成一种电惰性结合物，使Cu（Ⅱ）－TZAMB络合物的还原峰电流减小。通过循环伏安法、盐效应以及紫外－可见吸收谱证实了是由Cu(Ⅱ）－TZAMB络合物与DNA形成一种插入式的电惰性结合物而使其峰电流下降。根据这种峰电流下降可以测定DNA，测定结果令人满意。     

Studies on the Interaction of Beryllon Ш with Proteins by Voltammetric Technique and its Application

A new quantitative determination method of proteins using beryllon Ш by voltammetric technique was developed in this paper. In pH 3.5 Britton-Robinson (B-R) buffer solution, beryllon Ш can bind with human serum albumin (HSA) to form an electro-inactive supermolecular complex. Beryllon Ш has a well-defined voltammetric reduction peak at -0.38 V (vs. SCE) and the addition of protein in this solution can cause the decrease of the reductive peak current. Based on the decrease of the reduction peak current, a new electrochemical method for the determination of HSA was established with linear range of 1.0~40.0 mg/L and the detection limit of 1.0 mg/L. This method is further applied to the determination of real sample of healthy human serum.     

Studies on the Interaction of Beryllon Ⅲ with Proteins by Voltammetric Technique and its Application

A new quantitative determination method of proteins using beryllon Ⅲ by voltammetric technique was developed in this paper. In pH 3.5 Britton-Robinson (B-R) buffer solution, beryllon Ⅲ can bind with human serum albumin (HSA) to form an electro-inactive supermolecular complex. Beryllon Ⅲ has a well-defined voltammetric reduction peak at -0.38 V (vs. SCE) and the addition of protein in this solution can cause the decrease of the reductive peak current. Based on the decrease of the reduction peak current, a new electrochemical method for the determination of HSA was established with linear range of 1.0-40.0 mg/L and the detection limit of 1.0 mg/L. This method is further applied to the determination of real sample of healthy human serum.     

Electrochemical Studies of Pirarubicin and Its Interaction with DNA at a Co／GC Ion Implantation Modified Electrode

IntroductionIon implantation is a new material surfacemodification technique.It has been also applied tostudying the electrochemical behaviors of organicdrugs and biological materials as well as their de-terminations. This method offers good stability,reproductivity and catalytic activity[1] .Pirarubicin( THP) is an active highly effective and new antitu-moral anthracycline antibiotic,which has gainedwidespread clinical use in the chemotherapeutictreatment of a variety of human cancers.The d…     

电化学法研究罗丹明B与壳聚糖的相互作用

用电化学方法研究了罗丹明B与壳聚糖(CS)的相互作用,在pH 3.0的NaAc-HAc缓冲溶液中,罗丹明B在-0.67 V(vs.SCE)处有一个灵敏的线性扫描二阶导数极谱波,当加入一定量的CS后,反应体系的电化学信号发生变化,结果表明,罗丹明B与壳聚糖可形成结合物,结合物的峰电流在一定范围内与壳聚糖的浓度成正比,因而可用于测定壳聚糖的含量.此外,实验还探讨了罗丹明B与壳聚糖的最大结合数,为进一步研究有机染料与多糖的结合提供了理论基础.     

Barrier effect and coupled transport in the electrodialysis of metal complexonate solutions

The electrodialysis of an aqueous solution of an alkaline earth complex with ethylenediaminetetraacetic acid (EDTA) was studied in a wide range of current densities. The curve of the complexonate flow across an anionite membrane versus current density has three characteristic sections. The first section corresponds to a linear increase in the flow as a function of current density, the second to a decrease in the flow and decomposition of the complex (barrier effect), and the third to an increase in the complexonate flow due to the transport coupled with the flow of hydroxyl ions formed in the dissociation of water molecules at the interface of the solution and the anionite membrane. Conditions for complete separation of the singly and doubly charged cations were found.     

Voltammetric and spectroscopic studies on the interaction of anti-cancer herbal drug rutin with an anti-tuberculosis agent rifampicin

In this paper, the interaction of rutin (Rt) with rifampicin (RIF) has been investigated using voltammetric and spectroscopic techniques. With the addition of RIF into the Rt solution, both the reduction and oxidation currents of rutin decrease with few changes in the peak potentials and no new peaks appeared. The binding of Rt with RIF forms a kind of supramolecular complex Rt-RIF, which is electrochemically non-active. The experimental data showed that the formation of supramolecular complex is due to the electrostatic attraction of Rt with RIF. The binding reaction resulted in the decrease of the concentration of free Rt in the solution, and the decrease of the cathodic peak current of Rt. The stoichiometry of the Rt-RIF biocomplex was determinated to be 1: 1 by means of voltammetric data. The effect of pH on the binding reaction has been also studied. Based on the peak current values of Rt in the presence and absence of RIF, the binding constants of Rt-RIF at pHs 4, 7 and 9 were calculated as 0.72 × 10⁴ M⁻¹, 1.28 × 10⁴ M⁻¹ and 0.19 × 10⁴ M⁻¹, respectively. The experimental results indicate that there is a strength interaction between Rt and RIF in neutral pH. This binding reaction was supported by UV-Vis. and IR spectroscopy techniques.