过氧化氢氧化桑色素动力学荧光法测定痕量钴(Ⅱ)

建立了以Co(Ⅱ)为催化剂,催化过氧化氢氧化桑色素,使其荧光减弱的催化动力学荧光法。在pH 10.70的Na2B4O7?10H2O - NaOH缓冲溶液中,痕量钴(Ⅱ)离子对0.24%的H2O2溶液氧化 4.0×10-7 mol/L的桑色素溶液有明显的催化作用。在最大波长处( λex/λem = 416.5 nm / 556.4 nm),体系的荧光强度在一定的浓度范围内与Co(Ⅱ)的浓度呈线性相关,线性范围为0.8～8.0 μg/L,检出限为0.14 μg/L。优化了体系的最佳条件,考察了体系的离子干扰情况,对灰钙土和分子筛样品进行了分析检测,回收率分别为95.0～110.0%和98.9%～101.9%。     

桑色素褪色动力学光度法测定微量锰

研究了在pH9.5硼砂 氢氧化钠介质中,锰(Ⅱ)使桑色素溶液褪色的反应,建立了一种测定锰(Ⅱ)的新动力学光度法。锰(Ⅱ)的线性范围为0.10～0.50μg/25ml,检出限为4.5×10-6g·L-1。该法用于测定水中痕量锰,测定结果与原子吸收光谱法相一致。最大相对标准偏差为1 12%,回收率在96.6%～104.8%之间。     

Solid State Electrochemical Oxidation Mechanisms Of Morin in Aqueous Media

The mechanism of electrochemical oxidation of morin has been studied using cyclic, differential pulse and square‐wave voltammetry techniques in aqueous electrolyte with solid, insoluble morin hydrate mechanically transferred to a glassy carbon electrode surface, over a wide pH range. The oxidation mechanism proceeds in sequential steps, related with the hydroxyl groups in the three aromatic rings and the oxidation is pH dependent over part of the pH range the oxidation potentials are shifted to lower values with increasing pH. Oxidation of the 2′,4′dihydroxy moiety at the B ring of morin occurs first, at very low positive potentials, and is a one electron one proton reversible reaction. The hydroxyl groups oxidized at more positive potentials were shown to undergo an irreversible oxidation reaction.     

A sequential injection method for the determination of aluminum in drinking water using fluorescence enhancement of the aluminum-morin complex in micellar media

A robust and simple sequential injection (SI) method for the assay of aluminum ions in natural water is described. The method is based on the enhancement of the fluorescence of the aluminum-morin complex in the presence of a non-ionic surfactant (Tween-20). The fluorescence of the complex is monitored at an emission wavelength of 495 nm with excitation at 425 nm. The pH, morin concentration and the aspirated sample volume were optimized simultaneously using a chemometric method. The optimum operating conditions are: 150 μl aspirated sample volume, 20 μM morin concentration, a pH of 4.5 and 0.8% Tween-20. Using these optimum conditions a linear calibration curve was obtained from 50 to 1000 ppb. The detection limit was 3 ppb and the maximum relative standard deviation (n=5) of the method was 2.9%. The method was successfully applied for the determination of aluminum ions in natural water samples.     

Chemometrics-assisted spectrophotometric methods for simultaneous determination and complexation study of Fe(III), Al(III) and V(V) with morin in micellar media

Evolutionary factor analysis (EFA) and rank annihilation factor analysis (RAFA) were applied to resolve the two-way equilibrium spectrophotometric data belonging to the complexes of Fe(III), Al(III) and V(V) with morin (3,5,7,20,40-penta hydroxy flavone) as chelating agent in triton X-100 micellar media. Then, partial least square regression combined with genetic algorithm for wavelength selection (GA-PLS) was used for simultaneous determination of the metal ions. The parameters controlling behavior of the system were investigated and optimum conditions were selected. The predictive abilities of partial least squares regression (PLS) and genetic algorithm-partial least squares regression (GA-PLS) were examined in simultaneous determination of ternary mixtures of metal ions over the concentration range of 17.0-170.0ngml(-1), 25.0-180.0ngml(-1) and 40.0-325.0ngml(-1) for Fe(III), Al(III) and V(V), respectively. The relative standard errors for prediction of the ions in synthetic mixtures were lower than 5% and the mean recoveries in the tap water spiked samples were 104.2 and 101.7% for PLS and GA-PLS, respectively.     

混合表面活性剂对桑色素-镓(Ⅲ)荧光体系的研究

本文研究了混合表面活性剂十二烷基硫酸钠-Triton X-100存在下,Ga(Ⅲ)与桑色素的荧光形成反应。在pH为0.7的HCl-NaAc缓冲溶液中,镓的检测限为1.7ng/ml,线性范围为2～120ng/ml,本法的灵敏度高,选择性好,采用适当分离方法消除干扰后可用于地质试样中镓的测定。     

煤矸石中痕量钴的催化光度法测定

研究了在 pH 10.0的 Na2B4O7－ NaOH介质中,痕量 Co(Ⅱ )催化 H2O2氧化桑色素的褪色反应,褪色程度与 Co(Ⅱ )量在一定范围内呈线性相关。基于此,建立了一种测定痕量 Co(Ⅱ )的光度法。结果表明方法的检出限为 7.6× 10－ 2 μ g/L, Co(Ⅱ )质量浓度在 0.0～ 50.0 μ g/L范围内符合比尔定律。结合 N530萃取剂萃取分离,测定了煤矸石中的痕量钴。     

Synthesis and characterisation of morin-functionalised silica gel for the enrichment of some precious metal ions

Silica gel was firstly functionalised with aminopropyltrimethoxysilane obtaining the aminopropylsilica gel (APSG). The APSG was reacted subsequently with morin yielding morin-bonded silica gel (morin-APSG). The structure was investigated and confirmed by elemental and thermogravimetric analyses, IR and (13)C NMR spectral studies. Morin-APSG was found to be highly stable in common organic solvents, acidic medium (<2molL(-1) HCl, HNO(3)) or alkaline medium up to pH 8. The separation and preconcentration of Ag(I), Au(III), Pd(II), Pt(II) and Rh(III) from aqueous medium using morin-APSG was studied. The optimum pH values for the separation of Ag(I), Au(III), Pd(II), Pt(II) and Rh(III) on the sorbent are 5.7, 2.2, 3.7, 3.7 and 6.8, giving rise to separation efficiencies of 43.9, 85.9, 97.7, 60.9 and 91.0%, respectively, where the activity was found to be >90% in the presence of acetate ion. The ion sorption capacity of morin-APSG towards Cu(II) at pH 5.5 was found to be 0.249mmolg(-1) where the sorption capacities of Ag(I) and Pd(II) were 0.087 and 0.121mmolg(-1) and 0.222 and 0.241mmolg(-1) at pH 2.2 and 5.7, respectively. This indicates a 1:1 and 1:2 morin/metal ratios at pH 2.2 and 5.7, respectively. Complete elution of the sorbed metal ions was carried out using 10mL (0.5molL(-1) HCl+0.01molL(-1) thiourea) in case of Au(III), Pd(II), Pt(II) and Rh(III) and 10mL 0.5molL(-1) HNO(3) in case of Ag(I). Morin-APSG was successfully employed in the separation and preconcentration of the investigated precious metal ions from some spiking water samples yielding 100-folds concentration factor. The relative standard deviation (R.S.D.) and the T-test (|t|(1)) were calculated.     

Renewable Pencil Electrodes for Highly Sensitive Anodic Stripping Voltammetric Determination of 3‐Hydroxyflavone and Morin in Bulk Form and in Biological Fluids

An electrochemical anodic adsorptive stripping procedure for ultra‐trace assay of 3‐hydroxyflavone (3HF) and Morin at a renewable pencil electrode (PGE) in bulk form and in biological fluids is described. The nature of the oxidation process of 3HF and Morin taking place at the PGE was characterized by cyclic voltammetry. The results show that the determination of the oxidation peak current is the basis of a simple, accurate and rapid method for quantification of 3HF by square‐wave anodic stripping voltammetry. Determination of Morin was achieved by square‐wave anodic adsorptive stripping voltammetry of the formed Morin? Cu(II) complex at a PGE. Factors influencing the trace measurements of 3HF and the Morin? Cu (II) complex at a PGE are assessed. The limits of detection and quantitation for the determination of 3HF and Morin in bulk form and in biological fluids were determined. The statistical analysis and the calibration curve data for trace determination of 3HF and Morin are reported.     

桑色素与血清白蛋白相互作用热力学行为

利用荧光光谱、紫外-可见吸收光谱、圆二色谱、分子模拟等方法,在近似生理条件下,以牛血清白蛋白(BSA)为模式蛋白质,研究了桑色素(Morin)和血清白蛋白相互作用的热力学行为及其特征。荧光光谱结果表明:Morin能有效猝灭BSA的内源荧光,猝灭机制为静态猝灭;通过van’t Hoff方程,获取了BSA与Morin结合的热力学参数(?H?、?S?、?G?等),发现Morin与BSA两者之间的相互作用是一个吉布斯自由能降低的自发过程,且氢键和范德华力是二者结合的驱动力。通过分子模拟方法,发现Morin结合在BSA分子亚结构域IIIA的疏水腔内位点II,荧光共振能量转移结果表明Morin和与BSA的两个色氨酸残基的平均距离为3.09nm。圆二色谱结果表明Morin分子的结合会引起BSA分子α-螺旋含量降低。