高锰酸氧化茜素红褪色吸光光度法测定中成药中锰

关于锰的测定方法很多,应用最广泛的是高锰酸盐光度法,但此法灵敏度较低.近几年来利用氧化褪色,催化氧化褪色测定锰研究较多.在酸性介质中,高锰酸也能氧化茜素红,根据褪色前后吸光度差可测定微量锰.据此建立了高锰酸氧化茜素红褪色吸收光度法测定锰的方法.应用于中药金银花、厚朴中微量锰测定,结果满意.     

柠檬酸-罗丹明B体系阻抑动力学光度法测定痕量钴(Ⅱ)

催化动力学光度法以其灵敏高、检出限低,受到人们广泛重视.催化动力学光度法常用分析方法［1］有催化氧化动力学光度法、催化还原动力学光度法、催化荧光光度法、阻抑动力学光度法等.催化动力学光度法其检测限都在 ng·mL-1级,通常用于痕量分析,尤其适用于痕量金属离子测定.催化氧化动力学光度法测定痕量钴已有报道［2-5］,而阻抑动力学光度法测定痕量钴报道较少［6,7］.本文研究发现,在NH3·H2O-NH4Cl （pH=9.5）缓冲介质中柠檬酸对双氧水氧化罗丹明B的褪色反应具有阻抑作用,加入钴(Ⅱ)离子后,阻抑作用明显加强,且阻抑作用与加入的钴（Ⅱ）离子浓度成正比.据此建立了利用钴(Ⅱ)-柠檬酸对双氧水氧化罗丹明B褪色反应的催化阻抑动力学光度法来测量痕量钴的方法.该方法用于VB12药品针剂中痕量钴的测定获得较为满意的结果.     

吖啶橙作指示剂催化动力学法测定痕量钒的研究

在活化剂柠檬酸存在下,利用钒能催化加速溴酸钾氧化吖啶橙并使之褪色的新指示反应,建立了催化褪色光度法测定痕量钒的新方法,实验表明该法具有灵敏、准确、简便、快速等特点,并对其机理进行了初步探讨.     

偶氮胂M-溴酸钾催化动力学光度法测定痕量钒

钒是人体中重要的微量元素之一,测定痕量钒的催化光度法已有许多报道[1～5],但利用偶氮胂M试剂褪色为指示反应测定痕量钒目前尚未见报道.研究发现,在硫酸介质中,V(Ⅴ)对KBrO3氧化偶氮胂M(AM)的褪色反应有强烈的催化作用,且反应速率在一定条件下与溶液中V(Ⅴ)的浓度成正比,据此建立了一个测定痕量钒的新催化光度法并测定了催化反应的反应级数,确定了反应的速度方程.     

催化过氧化氢氧化曙红Y褪色光度法测定痕量铋（Ⅲ）

1 引言 在pH=4.34和加热条件下,痕量褪铋对过氧化氢氧化曙红Y的褪色反应有显著的催化作用,从而建立了催化褪色光度法测定痕量铋的新方法.测定Bi 的灵敏度(检出限为2.0×10-11 g/L)比文献报道的抑制KIO3氧化结晶紫、溴化十六烷基三甲铵存在下抑制H2O2氧化荔枝红色素和催化K2S2O8氧化[Ag(phen)2]+*[FIn]-离子缔合物等褪色光度法、苯基荧光酮-CTMAB光度法(ε=1.56×105 L*mol-1*cm-1)等高,本方法直接用于人发样与水样中痕量铋的测定,结果满意.     

Pt（Ⅳ）—三氯偶氮胂—溴酸钾催化分光光度法测定微量铂的研究

在硫酸介质中，微量铂的存在对溴酸钾氧化三氯偶氮胂的褪色反应有明显的催化作用，研究了催化分光光度法测定微量铂的新方法。该法灵敏度高，测定铂的线性范围为０．００－０．４０μｇ／１０ｍＬ。该方法已用于铂催化剂中微量铂的测定，结果令人满意。     

Pt(Ⅳ)-三氯偶氮胂-溴酸钾催化分光光度法测定微量铂的研究

在硫酸介质中，微量铂（Ⅳ）的存在对溴酸钾氧化三氯偶氮胂的褪色反应有明显的催化作用，研究了催化分光光度法测定微量铂的新方法。该法灵敏度高，测定铂的线性范围为０．００～０．４０μｇ／１０ｍＬ。该方法已用于铂催化剂中微量铂的测定，结果令人满意。     

生物油脂新型环氧化过程及机理研究

以金属有机化合物甲基三氧化铼(MTO)为催化剂, 双氧水为氧化剂新型化学方法合成环氧大豆油. 详细考察了催化剂在双氧水、溶剂和助剂等因素下的催化性能. 研究了该催化体系在其他油脂环氧化中的应用, 环氧产物的选择性在99%以上. 采用红外光谱法(IR)对产品进行表征. 通过紫外-可见分光光度法(UV-Vis)对催化剂的研究, 发现催化剂(MTO)在催化环氧化过程中形成催化中间体, 且催化活性很高. 对催化剂和双氧水相互作用机理及新型环氧化反应的机理进行了初步研究.     

催化动力学光度法测定痕量锌的研究

利用氨三乙酸为活化剂,锌催化过氧化氢氧化维多利亚蓝B褪色的指示反应,催化光度法测定痕量锌。方法具有一定的选择性。测量的线性范围为0.05~5.50μg.L-1,检出限为2.6×10-11g.mL-1,本法可直接用于头发、茶叶、火腿、牛肉等样品中痕量锌的测定,结果令人满意。     

人工神经网络阻抑动力学光度法同时测定邻苯二酚和间苯二胺

在硫酸性介质中,Fe(Ⅲ)能够催化H2O2氧化中性红褪色反应,邻苯二酚和间苯二胺都能阻抑该催化氧化褪色反应的速度,研究发现：两者对Fe(Ⅲ)催化H2O2氧化中性红褪色反应阻抑作用不具有加和性,根据这一现象,用人工神经网络处理非线性体系的优势进行数据处理,从而建立了一种新的测定邻苯二酚和间苯二胺混合物的人工神经网络阻抑动力学光度法。对5组混合样品进行测定,回收率均在95%-105%之间。     

HEPT类化合物的QSAR研究

为定量结构／活性相关性研究提取了量子化学参数,拓扑指数Am,分子连接性指数^mxt及疏水性常数,同时应用正交变换和最佳变量子集算法（Leaps-and-Bonds)进行了变量压缩和选择,进而实施了多元回归分析,并由此结果进行了HEPT类化合物（1－[(2-hydroxyethoxy)methyl]-6-(phenylthio)-thymine derivatives)的结构／活性关系的理论解释,进行了人工神经网络法对于该类化合物的活性预测,其结构明显好于多元回归法。     

Effect of the pH of the medium on the chemical shifts in the PMR spectra and on the distribution of the π-electron density

The dependence of the chemical shifts of the ring protons on the pH of the medium for a number of 4-hydroxyquinoline derivatives was studied by means of PMR spectroscopy. The dipolar and uncharged hydroxy forms exist in equilibrium in aqueous solutions. The effect of intramolecular hydrogen bonding on the character of the dependence of the chemical shift on the pH of the medium in the case of 3-piperidinomethyl-4-hydroxyisoquinoline was investigated. The possibility of the separate protonation of the ring nitrogen and the side-chain nitrogen in 3-piperidinomethyl-4-hydroxyisoquinoline was established. The distribution of the -electron density in 4-hydroxyisoquinoline is in good agreement with its chemical behavior.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1546–1549, November, 1971     

Effect of the pH of the medium on the chemical shifts in the PMR spectra and on the distribution of the π-electron density

The dependence of the chemical shift of the ring protons on the pH of the medium for a number of 3-hydroxyquinoline derivatives was studied by PMR spectroscopy. The regions of ionization of the molecules, which correspond to the ranges of acidic, neutral, and alkaline media, were found. In D₂O, 3-hydroxyquinoline is present only in the uncharged hydroxy form. The presence of intramolecular hydrogen bonding in 4-dimethylaminomethyl-3-hydroxyquinoline has a substantial effect on the character of the dependence of the chemical shift on the pH of the medium; the existence of separate protonation of the nitrogen atoms of the ring and the side chain of 4-dimethylaminomethyl-3-hydroxyquinoline was established. The distribution of the -electron density in the 3-hydroxyquinoline molecule is in good agreement with its chemical behavior during electrophilic substitution.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1540–1545, November, 1971.     

From the Micro- to the Macro-: Managing the Conservation of the Warship,Vasa

Sweden's famous warship, Vasa, sank on her maiden voyage in August 1628, and remained on the bottom of Stockholm harbour for 333 years. Raised in 1961, she became the first large-scale wooden object to be treated with polyethylene glycol (PEG). In the summer of 2000 a number of acidic salt precipitations were noticed on the surface of the ship and on wooden artefacts in the storerooms. An international research project has been established to look into the causes of this problem and suggest possible re-treatments. Meanwhile projects are underway to monitor movements in the ship, to build a better support system, and to replace the thousands of iron bolts holding the structure together, while a sophisticated new climate system has recently been installed in the museum.