氯酸钾－二甲基黄－钒（Ⅴ）体系催化光度法测定痕量钒

本文研究了氯酸钾－二甲基黄－钒（Ⅴ）体系催化光度法测定痕量钒的条件及应用。钒含量在０～６０ｎｇ／１０ｍＬ范围内与ｌｇ（Ａ＿０／Ａ）有良好的线性关系，检出限１．０×１０￣（－１１）ｇ／ｍＬ。方法简便快速，应用于水及食品中痕量钒测定，结果满意。     

反相高效液相色谱法同时测定果汁中8种添加剂

建立了反相高效液相色谱法（ＲＰ－ＨＰＬＣ）同时直接测定进口果汁中柠檬黄和苋菜红等８种添加剂含量的方法。色谱柱为Ｈｙｐｅｒｓｉｌ　ＢＤＳ　Ｃ１８柱（２５０ｍｍ×４．０ｍｍｉ．ｄ,５μｍ）,流动相为甲醇／０．０１ｍｏｌ／Ｌ乙酸铵,梯度洗脱,流速为 １．０ ｍＬ／ｍｉｎ,柱温为 ４０℃,ＤＡＤ紫外检测器波长为 ２３０ ｎｍ。在此色谱条件下,各组分在１０ ｍｉｎ内均得到良好分离。平均回收率为 ９０％～１１４％,相对标准偏差 １．３％～８．０％。     

PAR-吖啶黄能量转移荧光猝灭法测定痕量铁(Ⅱ)的研究

对 4 (2 吡啶偶氮 ) 间苯二酚 (PAR)与吖啶黄间荧光能量转移进行了探讨 ,研究了其能量转移的最佳条件 ,并应用该体系测定痕量铁 (Ⅱ ) ,由此建立了能量转移荧光测定痕量铁的新方法。在λex/em =46 5nm/5 0 5nm ,十二烷基硫酸钠 (SDS)作用下 ,pH =9 2时 ,吖啶黄与PAR 铁 (Ⅱ )络合物间能发生有效能量转移 ,使吖啶黄的荧光猝灭。铁的量在 0～ 10 μg·L-1范围内呈良好的线性关系。最低检出限 0 0 6 μg·L-1。该方法用于水样、发样中痕量铁的测定 ,结果满意。     

乙醇敏化钛黄与蛋白质作用的共振光散射光谱研究及其分析应用

研究了在乙醇存在下钛黄（TY）与蛋白质作用的共振光散射（RLS）光谱特征 。基于RLS的增强,建立了一种测定蛋白质的新方法。考察了各种影响因素,在优 化条件下确定了RLS强度与蛋白质浓度之间的关系。当TY浓度为4 * 10~(-5)mol· L~(-1)时,牛血清白蛋白（BSA）、人血清白蛋白（HSA）和溶菌酶(lysozyme)的线 性响应范围分别为0.1～6.0 μg·mL~(-1), 0.1～5.0 μg·mL~(-1), 0.2～3.0 μg·mL~(-1),检出限分别为12.7 ng·mL~(-1), 11.6 ng·mL~(-1)和18.8 ng· mL~(-1)。三种合成样品五次平行测定的回收率和相对标准偏差（RSD）分别为96. 0%～102.3%和0.8%～3.2%。将该方法与经典的Bradford方法分别用于人血清试样中 蛋白的测定,两种方法的分析结果经F-检验和双总体T-检验证明无显著性差异。     

Raman Spectrum of Vanadium-Zirconia Yellow Pigment

Monoclinic vanadium-zirconia yellow pigments were prepared by gelling mixtures of zirconium n-propoxide and vanadyl acetylacetone. The nature of interactions between the host ion and the foreign cation in the vanadium-zirconia pigment was investigated in order to contribute to a better understanding of the origin of this pigmenting system using Raman scattering measurements. The Raman spectra of powdered samples of the vanadium-zirconia pigment recorded between 100 and 1400 cm^?1 show the peaks at 991, 701, and 403 cm^?1 assigned to the asymmetric and symmetric stretching and bending vibrations of the V⁴⁺ = O bonds, respectively. The assignment of these peaks was discussed by comparison with Raman spectra of vanadium oxides and on the basis of V-O bond distances deduced from the Hardcastle and Wachs equation and from the valence state of the vanadium cation calculated by Brown in the valence sum rule. This suggests that the V⁴⁺ cations replace Zr⁴⁺ in sevenfold coordinated site in the monoclinic zirconia structure. The V⁴⁺ cation allowing the d-d electronic transition is related to the origin of the lemon yellow coloration.     

Removal of organic dye pollutants from wastewater by electrochemical oxidation

The removal of chemical oxygen demand (COD) and color from simulated dye wastewater containing organic dyes, direct yellow 4, C₂₆H₂₀N₄O₈S₂Na₂ and acid yellow 17, C₁₆H₁₀O₇N₄S₂Cl₂Na₂ experimentally investigated using an electrochemical undivided cell reactor with Pt as anode and steel as cathode. Particular attention was paid to probe the effect of supporting electrolyte (NH₄Cl), cell voltage, pH, and treatment time on the electrochemical treatment efficiency. Experiments were also carried out using 0.2?M NH₄Cl as supporting electrolyte under the condition of free pH. The experimental results showed that the process could efficiently remove the color and COD from simulated dye waste water. The overall COD removal reached at 69.9% by using supporting electrolyte and increasing voltage. The process can be described by pseudo first-order kinetics for the removal of COD.     

Electrochemical Characterization and Electrocatalytic Application of Gold Nanoparticles Synthesized with Different Stabilizing Agents

Gold nanoparticles (AuNPs) have unique properties, making them attractive for electronic and energy‐conversion devices and as (electro)catalysts for electrochemical sensors. In addition to the size and shape of AuNPs, the electrocatalytic properties of AuNP‐sensors are also determined by the stabilizing agent used in their synthesis. Here, AuNPs were synthesized with citrate, alginate and quercetin, obtaining spherical and negatively charged nanoparticles. The AuNPs were used to modify glassy carbon electrodes (AuNPs/GCE), which were characterized by scanning electron microscopy and electrochemical techniques. The AuNPs/GCE showed aggregates of different sizes and degrees of dispersion on the electrode surface depending on the stabilizing agent. The AuNP's aggregates affect the homogeneity of the film, the reproducibility of the electrodes and their response in buffer solution. Finally, to evaluate the electrocatalytic ability of the AuNPs/GCE, we studied the oxidation of two analytes with opposite charges: (1) sunset yellow (negative) and (2) hydrazine (positive). Compared with GCE, the AuNPs/GCE showed good electrocatalytic properties for hydrazine, increasing the current up to 50 % and shifting the potential by almost 400 mV, depending on the AuNP used. For the negatively charged analyte, the current decreased up to 50 % and no shift in potential was observed. Thus, the electrocatalytic properties of the AuNPs showed to be highly dependent on the nature of the analyte.     

Simultaneous Determination of Sunset Yellow and Ponceau 4R in Gelatin Powder by Derivative Spectrophotometry and Partial Least-Squares Multivariate Spectrophotometric Calibration

ABSTRACT

Two methods for the simultaneous determination of Sunset Yellow and Ponceau 4R in gelatin powders by first derivative spectrophotometry and by partial least-squares multivariate spectrophotometric calibration are described. These procedures do not require any separation step. These methods were applied to determine both colorants in commercial gelatin powders and the results obtained were compared. A good statistical agreement was obtained between the results.     

全固态腔内SHG/SFG多波长黄光激光器

报道了一种利用大功率激光二极管端面抽运Nd…YAG激光晶体产生基频光,并通过非线性晶体的腔内倍频(SHG)与和频(SFG),实现多个二次谐波同时连续输出的多波长黄光激光器。将Nd…YAG晶体的1112.1、1115.9、1122.7nm谱线作为基频光,利用LBO和BIBO进行非线性光学频率变换,同时获得了三个倍频光及三个和频光激光输出。从理论上对基频光同时受激跃迁和非线性频率变换相位匹配进行了分析。实验结果与理论分析表明,当基频光的性能相对接近时,合理地选择性能较好的非线性晶体对基频光同时进行倍频和和频是获得全固态多波长激光器的一种实用方法,合理地设计激光器谐振腔能够提高激光器的稳定性。     

Proton NMR relaxation study of molecular dynamics of chromonic liquid crystal Edicol Sunset Yellow

Proton nuclear magnetic resonance (¹H NMR) relaxometry, over about five decades in Larmor frequency, and pulsed field gradient NMR were used to study the molecular dynamics in the chromonic nematic and isotropic phases of stacked molecules of the binary mixture composed by Edicol Sunset Yellow (ESY) and deuterated water. Our results evidence that in both phases collective motions are responsible for the spin-lattice relaxation dispersion in the Larmor frequency range below 1 MHz. In the nematic phase, the collective motion are attributed to columnar undulations within the stacked molecules, while, in the isotropic phase, the results are explained by local order fluctuations due to the formation of the stacks. The high frequency dispersion was explained by individual molecular motions like rotations around and perpendicular to the stack axis, and also self-diffusion.