Fe(Ⅲ)-KIO4-苋菜红体系催化动力学单扫描示波极谱法测定痕量铁

研究了在H2SO4介质中,痕量Fe(Ⅲ)催化KIO4氧化苋菜红的褪色反应.提出了催化动力学单扫描示波极谱法测定痕量铁的新方法.在1.6×10-3mol/L H2SO4介质中,苋菜红在汞电极上产生1个还原峰,峰电位为-0.186 V(vs.SCE)左右.氧化剂KIO4存在时,在-0.186 V处的峰电流的降低与加入Fe(Ⅲ)离子在0～0.04μg/mL范围内呈良好的线性关系,检出限4.2×10-9g/mL.同时研究了该方法适宜的反应条件,应用本方法测定中草药和水中铁的含量,回收率在98%～101%之间,结果满意.     

以鸡冠花红为电化学探针线性扫描极谱法测定阿米卡星

在pH 4.0的介质中鸡冠花红在-250 mV（vs.SCE）处有一个良好的二阶导数极谱还原峰,当其与阿米卡星作用后,其还原峰电位基本不变而峰电流明显下降,峰电流的下降值与阿米卡星的质量浓度在0～40.0 mg/L范围内呈良好的线性关系,其线性方程为△ip＂（nA）=-5.48＋72.28ρ（mg/L）,相关系数r=0.9996,检出限为1.0 mg/L.优化了线性扫描极谱法测定阿米卡星的试验条件,并将该方法应用于市售药物中阿米卡星的测定.     

Morphology-controlled electrochemical sensing amaranth at nanomolar levels using alumina

Different-shaped aluminas were readily prepared via hydrothermal reaction. It was found that the morphology and the electrochemical sensing properties of alumina were heavily dependent on the reaction time. When extending the reaction time from 6 h to 24 h, the obtained alumina samples changed from amorphous bumps to regular microfibers in diameter of 200 nm, as confirmed by scanning electron microscopy. Transmission electron microscopy observation revealed that longer reaction time was beneficial for the formation of porous and uniform fiber-like structures. Electrochemical tests proved that alumina microfibers were more active for the oxidation of amaranth and exhibited much higher enhancement effect, compared with alumina bumps. On the surface of alumina microfibers, the oxidation peak currents of amaranth increased remarkably. The influences of pH value, amount of alumina microfibers, and accumulation time on the signal enhancement of amaranth were discussed. As a result, a novel electrochemical method was developed for the detection of amaranth. The linear range was from 1 to 150 nM, and the detection limit was 0.75 nM after 1-min accumulation. The analytical application in drink samples was investigated, and the results consisted with the values that obtained by high-performance liquid chromatography.     

催化鸡冠花红褪色动力学光度法测定痕量铜

稀硫酸介质中,基于痕量铜(Ⅱ)对溴酸钾氧化鸡冠花红褪色反应具有较强的催化作用.建立了一种高灵敏度测定痕量铜(Ⅱ)的新催化动力学法.在优化条件下,方法的线性范围为0.0024-0.56μg/mL,检出限为4.4×10-7g/L用于水样中痕量铜(Ⅱ)的测定,结果满意.     

催化动力学光度法测定青霉素G及其机理研究

研究了在青霉素G存在下双氧水氧化苋菜红的褪色反应,建立了催化动力学光度法测定微量青霉素G的方法.方法线性范围为0.20～4.00μg/mL,回归方程y=-0.015p(μg/mL)+0.311,r=0.9998;方法线性范围为4.00～50.0μg/mL,回归方程y=0.001p(μg/mL)+0.280,r=0.99...     

Bismuth Film Electrode as an Alternative for Mercury Electrodes: Determination of Azo Dyes and Application for Detection in Food Stuffs

Bismuth electrodes were investigated and exhibit electrochemical properties similar to mercury electrodes but with much lower toxicity. An electrochemical application of bismuth film modified glassy carbon electrode for azo dyes determination was investigated. The plating step was optimized in order to achieve its analytical efficiency. A plating potential of ?0.9 V in a solution of 200 mg/L Bi(NO₃)₃, 0.5 M HNO₃ for 100 s yields to a suitable electrode (in terms of stability and detection). Azo dyes such as azorubine (i.e., carmoisine, E122), amaranth (E123), ponceau 4R (i.e., new coccine, E124) and allura red (E129) were determined by differential pulse voltammetry in a NaCl solution in the concentration range of few ppm to 100 ppm. The reproducibility of the signal, characterized by the relative standard deviation, was found to be less than 5%, the detection and quantification limits were few mg/L. The influence of other food components on the signal was studied and the applicability was tested on real beverages samples.     

水杨酸抑制亚硝酸根催化鸡冠花红褪色反应的伏安法研究及其应用

用两阶导数未波极谱法作监测技术研究了水杨酸对ＮＯ２＾－催化ＢｒＯ３＾－氧化鸡冠花工褪色反应的抑制行为，测定了该抵制体系的反应级数、动力学方程及表观活化能，建立了动力学抑制法测定水杨酸的新方法。方法的线性范围为０．０５～０．６５ｍｇ／Ｌ，检测限为０．０２６ｍｇ／Ｌ，与已报道的各种水杨酸测定方法相比，该法具有仪器简单、操作方便、灵敏度较高等优点。用于爽肤水与润肤露中微量水杨酸的测定。结果满意。     

Preparation of microparticles composed of cinnamoyl gelatin and cinnamoyl alginate by spray-drying method and effect of UV irradiation and pH value on their release property

Microparticles composed of cinnamoyl gelatin (CinGel) and cinnamoyl alginate (CinAlg) were prepared as a UV irradiation- and pH-responsive carrier by a spray-drying method. CinGel and CinAlg were prepared by a condensation reaction. Using a colorimetric method, the gelatin to CA mass ratio and the alginate to CA mass ratio were calculated to be 1:0.04 and 1:0.02, respectively. The complexation of CinGel and CinAlg in aqueous solution took place when the medium was acidic (e.g., pH 4.0) and the maximum complexation was obtained when the CinGel/CinAlg mass ratio was 7:3. On SEM photographs, some spray-dried CinGel/CinAlg particles were spherical and others were irregularly shaped, and the diameter was a few to tens of micrometers. The release degrees of amaranth loaded in UV-treated microparticles were lower than those of the dye loaded in UV-untreated ones, possibly because of the photo cross-linkage of CinGel and CinAlg. Regardless of whether the microparticles were UV-treated, the release degree at pH 4.0 was significantly lower than the release degree at pH 6.0 and pH 8.0, possibly because of complexation of CinGel and CinAlg under the acidic condition.     

苋菜红褪色光度法测定痕量铜

本文研究了在 NH3- NH4Cl介质中 ,铜催化过氧化氢氧化苋菜红的褪色反应及其动力学条件 ,测定了反应级数和表观活化能 ,建立了测定痕量铜的新方法。该方法的检出限为 1 .6× 1 0 - 1 0 g/ m L,线性范围为0 - 2 .0 μg/ 2 5 m L,用于测定水中痕量 Cu,与原子吸收法的测定结果一致。     

用鸡冠花红线性扫描极谱法测定蛋白质及其应用

在pH3．0的Britton—Robinson(B-R)缓冲溶液中，鸡冠花红与蛋白质能够发生相互作用形成超分子复合物，使鸡冠花红在-0．25V(vs．SCE)处的极谱还原峰峰电流下降。在最佳条件下，峰电流的下降值同人血清白蛋白(HSA)的浓度在1．0～20．0mg／L范围内呈线性关系，其线性回归方程为△ip″(nA)=184．86 111．23c(mg／L)．r=0.987。将该方法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。此方法还可应用于牛血清白蛋白、牛血红蛋白、卵清白蛋白等蛋白质的测定。