靛蓝胭脂红-高碘酸钾-草酸钠催化光度法测定钢中微量钒

研究了在1 mol/L磷酸介质中，钒(V)对KIO4氧化靛蓝胭脂红褪色反应的催化作用及草酸钠的活化作用，建立了一种测定钒的方法。无草酸钠时该体系为准零级反应，表观活化能为76.7 kJ/mol，在22℃时钒量在0～5mg/L范围内与?A呈线性，检出限为0.1　mg/L。在草酸钠存在下则为准一级反应，表观活化能为60.1 kJ/mol，钒量在0～mg/L范围内与1g(A0/A)呈线性，检出限为0.02mg/L。提高介质酸度，可显著降低反应温度。在NaF及尿素存在下，大多数常见离子无干扰。本法简便快速，选择性和灵敏度较高，用于钢中微量钒的直接测定，结果满意。     

Synthesis of CuS nanoparticles loaded on activated carbon composite for ultrasound‐assisted adsorption removal of dye pollutants: Process optimization using CCD‐RSM,equilibrium and kinetic studies

In this study, the CuS nanoparticles loaded on activated carbon (CuS‐NPs‐AC) composite was synthesized and then, characterized by XRD and FE‐SEM analyses. The prepared composite was used as a potential adsorbent for the simultaneous ultrasound‐assisted removal of Indigo Carmine (IC) and Safranin‐O (SO). The CuS‐NPs‐AC dose (0.01‐0.03 g), sonication time (1‐5 min), initial SO concentration (5‐15 mg L^‐1) and initial IC concentration (5‐15 mg L^‐1) as expectable effective parameters were studied by central composite design (CCD) under response surface methodology (RSM) to obtain an useful knowledge about the effect of simultaneous interaction between IC and SO on their removal percentage. The optimum SO and IC removal percentages were determined to be 98.24 and 97.15% at pH = 6, 0.03 g of the CuS‐NPs‐AC, 3 min sonication time, 12 and 10 mg L^‐1 of IC and SO. The values of coefficient of determination (R²) for SO and IC were 0.9608 and 0.9796, respectively, indicating the favorable fitness of the experimental data to the second order polynomial regression model. The isotherm data were well correlated with Freundlich model. The maximum monolayer adsorption capacities of 87.5 and 69.90 mg g^‐1 at room temperature for IC and SO in the investigated binary system expressed the high efficiency of the novel adsorbent for water cleanup within a short time. The investigation of correlation between time and rate of adsorption revealed that IC and SO adsorption onto the CuS‐NPs‐AC followed pseudo‐second‐order and intra‐particle diffusion simultaneously.     

Catalytic reactivity of new Ni(II), Cu(II) and Sn(II) complexes for decolorization of indigo carmine in aqueous solution,high efficiency of copper complex

A new Ni(II), Cu(II) and Sn(II) Schiff base complexes were synthesized in this work. The characterization of the new complexes is carried out by elemental analysis, FT‐IR, UV–Visible, ¹H NMR and ¹³C NMR spectroscopy, conductance analysis, magnetic measurements and thermal gravimetric analysis. It was found that the ligand behaves as a dibasic bidentate which coordinated to the metal center through two deprotonated hydroxyl groups to form tetrahedral complex with Ni(II) and octahedral complex with Cu(II). The ligand acts as neutral bidentate through azomethine nitrogen and thiazol sulfur to form octahedral complex with Sn(II). The synthesized complexes are evaluated as catalysts for oxidative degradation of indigo carmine dye using H₂O₂ as oxidant and the efficiency of the catalysts is determined. The copper complex shows the best catalytic action with efficiency 92.17% after 25 min.     

溴酸钾氧化靛红催化光度法测定痕量亚硝酸根

基于磷酸介质中ＮＯ２＾－催化溴酸钾氧化靛红的褪色反应，建立了测定痕量ＮＯ２＾－的新方法，并讨论了其动力学条件。方法检测限为１．３６×１０＾－６ｇ／Ｌ，线性范围０．３￣２μｇ／２５ｍＬ，方法简便，已用于环境水样中痕量ＮＯ２＾－的测定。     

支持向量回归分光光度法同时测定胭脂红与果绿含量

在波长300～600 nm范围内,测定胭脂红和果绿混合体系的吸光度,用支持向量回归(SVR)方法进行建模,建立了支持向量回归分光光度法同时测定胭脂红和果绿的方法,并用该法对模拟样品进行测定.结果表明,模拟样品中胭脂红和果绿的平均回收率分别是97.645%和100.895%,结果令人满意.     

亲水相互作用色谱柱串联C18柱高效分析饮品中的胭脂红

建立了亲水相互作用色谱柱(HILIC)串联C18柱的方法,高效分离实际样品中的胭脂红,并对色谱柱的串联顺序以及色谱分离条件进行优化。结果表明:当HILIC柱在前C18柱在后,流动相为乙腈-乙酸铵(5 mmol/L)=91∶9(V/V),流速为0.9 mL/min,柱温为25℃,检测波长为508 nm时,此时胭脂红的分离效果最佳。在最佳的色谱分离条件下,选用两种市售饮品进行实际样品的测定,回收率在81.2%~119%。方法适用于水相样品中的强极性物质的高效分离与分析。     

催化荧光光度法测定血红蛋白

基于血红蛋白(Hb)对过氧化氢氧化靛蓝胭脂红体系的催化作用,建立了模拟酶催化荧光光度法测定血红蛋白的新方法并对催化氧化反应的机理进行了初步探讨。实验发现体系的荧光强度与血红蛋白浓度在6.20×10-11~7.75×10-8mol/L范围内线性关系良好,方法的检出限为1.67×10-11mol/L。方法用于人血中血红蛋白含量的测定,回收率为98.8%~103.2%。     

催化动力学分析法测定食品中的痕量锌

在H2SO4介质中,痕量锌能灵敏地催化K2S2O8氧化靛蓝胭脂红褪色反应。研究了该催化褪色反应的最佳动力学条件和参数,建立了测定痕量锌的催化动力学新方法,方法检出限为4.18×10-8g/mL,线性范围为(0.25-3.5μg/25)mL,将其用于食品(黄豆、豌豆、奶粉)中锌的测定,获得了满意的结果。     

Online UV–visible spectroscopy and multivariate curve resolution as powerful tool for model-free investigation of laccase-catalysed oxidation

The laccase-catalysed transformation of indigo carmine (IC) with and without a redox active mediator was studied using online UV–visible spectroscopy. Deconvolution of the mixture spectra obtained during the reaction was performed on a model-free basis using multivariate curve resolution (MCR). Thereby, the time courses of educts, products, and reaction intermediates involved in the transformation were reconstructed without prior mechanistic assumptions. Furthermore, the spectral signature of a reactive intermediate which could not have been detected by a classical hard-modelling approach was extracted from the chemometric analysis. The findings suggest that the combined use of UV–visible spectroscopy and MCR may lead to unexpectedly deep mechanistic evidence otherwise buried in the experimental data. Thus, although rather an unspecific method, UV–visible spectroscopy can prove useful in the monitoring of chemical reactions when combined with MCR. This offers a wide range of chemists a cheap and readily available, highly sensitive tool for chemical reaction online monitoring.