Spectrophotometric Study on Some Amino Acid Drugs with Chloranil and its Analytical Application

The interaction between amino acid drugs, aminobutyric acid, carbocisteine and levodopa, with chloranil was studied spectrophotometrically. The conditions were investigated and optimized. The interaction obeyed Beer＇s law over the range of 0.2-8.7, 1.2-20 and 2-26.4 μg/mL for aminobutyric acid, carbocisteine and levodopa, respectively. The validity was compared with that by the official methods^1,3,5 and the recovery studies of standard addition method, the result is satisfactory. The proposed method has been successfully applied to the determination of the above drugs in tablets.

PHOTOINDUCED ADDITION REACTIONS OF CHLORANIL WITH FURAN DERIVATIVES

Photoinduoed reaction of chloranil (TCBQ) with 2-methylfuran la and 2,5-dimethylfuran 1b in benzene gave addition products 2a and 2b respecvely together with tetrachlorohydroquinone 3. A mechanism of sequential electron and proton transfer from la or 1b to ~3TCBQ followed by coupling of the furfuryl and semiquinone radical pairs was proposed and is evidenced by the photo-CIDNP studies of the TCBQ-1a and TCBQ-1b systems.

Spectrophotometric Study on the Interaction of Water with Chloranilic Acid and its Analytical Application

The reaction between chloranilic acid and water in alcohol was studied spectrophotometrically. The conditions of reaction were investigated in detail. The stable purple complex with an absorption wavelength at 530 nm was produced from the reaction between chloranilic acid and water. As a method for determination of H2O, Beer’s law was obeyed in range of 0-6.0 % or 0-8.0 % (V/V) with the detection limit of 0.13 %. The relative standard deviation (RSD) was less than 2 %. The proposed method has been applied to determination of trace amount of water in ethanol, flour and food flavoring, respectively. The recoveries of water in samples were 97～102 %.

A CIDNP STUDY OF THE PHOTOREACTIONS OF METHYLFURANS WITH CHLORANIL

The CIDNP observations indicated that photoreaction of methylfurans with chloranil resulted not only furylmethyl hydroxyphenyl ethers via radical pairs but induced furyl radical isomerization to the derivatives of cyclopropene,propadiene and pyran.

Syntheses and Magnetism of Binuclear Tb(Ⅲ)-Tb(Ⅲ)Complexes with Dianion of Chloranilic Acid as Bridging Ligand

The syntheses, spec(?) complexes are of significance for understanding mechanisms of magnetic interaction between metal ions and the exploitation of the synthesis of molecular magnetic materials. There were a few works reported previously on the syntheses and magnetic in-

Spectrophotometric Determination of Lamivudine Using Chloranilic Acid and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)

A spectrophotometric method for the assay of lamivudine in pure form and in dosage form was developed in this study. The method was based on charge-transfer complex formation between the drug, which acted as n-donor while chloranilic acid and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) acted as a p-acceptor in a non-aqueous solvent in each case. Chloranilic acid was found to form a charge-transfer complex in a 1:1 stoichiometry with lamuvudine (lamivudine-chloranilic acid) with a maximium absorption band at 521 nm. Also, DDQ was found to form a charge-transfer complex in a 1:1 stoichiometry with lamivudine (lamivudine-DDQ) with a maximium absorption band at 530 nm. The pH was obeyed at acid range. The complexes obeyed Beer’s law at a concentration range of 0.04 - 0.28 mg/ml. The thermodynamic parameters calculated at different temperatures included the molar absorptivity, association constant, free energy change, enthalpy and entropy. The proposed method has been conveniently applied in the analysis of commercially available lamivudine tablet with good accuracy and precision.

Synthesis of （thia）Calixarene-based exTTF Derivatives and Their Electron Transfers Towards p-Chloranil and C60

Two novel （thia）calixarene-based exTTF derivatives（3a and 3b） were prepared by Mitsunobu reactions in toluene using diethyl azodicarboxylate（DEAD） and triphenylphosphine（PPh3） system. The cyclic voltammograms of compounds 3a and 3b were provided, and two electron-irreversible waves with redox potentials were observed. Meanwhile, the intermolecular electron transfer（ET） properties of both compounds 3a and 3b towards p-chloranil（Q） and C60 were investigated via UV-Vis and fluorescent spectroscopies, respectively. The results indicated that the in- troduced nonoxidable metal ions（Al^3＋, Pb^2＋, Sc^3＋） might promote the intermolecular ET from compounds 3a and 3b towards Q ensembles, whereas the effects of Sc^3＋ were the most impressive. Furthermore, the effects of the same metal ions（Al^3＋, Pb^2＋, Sc^3＋） added for compound 3b were greater than those for compound 3a. Additionally, the pho- toinduced intermolecular ET from compounds 3a and 3b towards C60 was observed.

Novel clicked tetrathiafulvalene-calix[4]arene assemblies:Synthesis and intermolecular electron transfer toward p-chloranil

Two tetrathiafulvalene-calix[4]arene assemblies （TTF-calix-1 and TFF-calix-2） have been synthesized by the click reaction. Both their cyclic voltammograms show, as expected, two one-electron quasi- reversible redox behavior. The UV-vis absorption spectra studies show that these two assemblies undergo progressive oxidation at the TFF moiety in presence of increasing amounts of Cu2＋ or Hg2＋. Moreover, the absorption studies show intermolecular electron transfer between compounds TrF-calix- I or TI＇F-calix-2 and p-chloranil may be promoted by specific metal ions such as Pb2＋, Sc3＋ etc.

A study on the mechanism of reaction between BNAH and chloranil:Evidence for electron transfer

The reaction between chloranil and N-benzyldihydronicotinamide(BNAH)in borate buffer/DMF was investigated.The reaction mixture gave a strong esr signal,which is consistent with that of chloranil anion radical,and tetrachlorohydrophenol(QH_2)and N-benzylnicotinamide (BNA^+)were obtained as the sole products.When the reaction was run in benzene solution,a green coloured charge-transfer complex between the reactants could be isolated,which decomposed in polar solvents to give BNA-+ and QH_2.Based on kinetic studies by esr spectroscopy by the stopped-flow technique,a two-step electron-transfer mechanism for the reactionis proposed in contrast to the hydride-transfer mechanism reported in the literature.

胶束增稳荷移反应紫外分光光度法测定洛美沙星

提出了一种基于胶束增稳荷移反应测定洛美沙星的紫外分光光光度法 ,研究了在阳离子表面活性剂溴化十六烷基吡啶 (CPB)胶束体系中电子给体洛美沙星与电子受体四氯对苯醌之间的荷移反应产物的紫外光谱性质。发现CPB对洛美沙星与四氯对苯醌的荷移反应络合物有显著的增稳效应。洛美沙星的浓度在0 .8～ 5 4mg L范围内符合比尔定律 ,r =0 .9994。在测定波长 32 3nm处 ,络合物的表观摩尔吸光系数为 3.5 6×10 - 4L·mol- 1 ·cm- 1 。本方法用于片剂中洛美沙星含量的测定 ,其回收率为 97.8%～ 10 0 .5 % ,相对标准偏差为0 .9%～ 2 .4 %。

有机溶剂中微量水的荷移光谱法测定

研究了氯冉酸与有机溶剂中水的反应 ,确定了反应条件。氯冉酸与水的络合物的最大吸收波长为5 3 0nm。在乙醇、甲醇、正丙醇、异丙醇、正丁醇、正庚醇、正己醇溶剂中 ,水的含量分别在 0～ 5 % (V V)或 0～8% (V V)范围内呈线性关系 ,相关系数为 0 .998或 0 .999;该方法重现性好 ,灵敏度高 ,操作简单 ,用于测定乙醇中微量水的含量 ,与标准值相符 ;加入回收法测得甲醇中水的回收率分别为 98%～ 1 0 3 % ,结果令人满意。

克霉唑与氯冉酸的荷移反应及其测定

克霉唑与氯冉酸在丙酮介质中发生电荷转移反应 ,生成 1∶1型络合物 ,该络合物的λmax=5 2 5nm ,表观摩尔吸光系数是 1.2 2× 10 3 L·mol-1·cm-1,药物浓度在 0～ 30 0mg/L范围内符合比耳定律 ,6次测定的相对标准偏差为 1.4 % ,回收率在 97%以上。用拟定的方法测定药物片剂中有效成分的含量 。

“永固紫”染料和四氯苯醌中多氯代二苯并二噁/呋喃的分析

采用浓硫酸对5种不同来源的四氯苯醌和“永固紫”染料样品进行溶解分散,用甲苯提取和多层色谱柱纯化,利用同位素稀释法及高分辨气相色谱质谱(HRGCHRMS)联用技术,测定了其中的多氯代二苯并二口恶口英呋喃(PCDDF)的质量比。结果表明“永固紫”染料及其原料中PCDDF的质量比异常高,八氯代二苯并二口恶口英呋喃(OCDDF)已达到μgg级甚至100μgg级,七氯代二苯并二口恶口英呋喃(HpCDDF)和六氯代二苯并二口恶口英呋喃(HxCDDF)质量比也达到ngg级。所有样品的毒性当量浓度(TEQ)均已超过10pgg的危险水平,是纺织品中PCDDF的一类重要污染源。并进一步探讨了PCDDF的来源。

阿苯达唑与氯冉酸的荷移反应与应用

研究并确定了阿苯达唑与氯冉酸的荷移反应条件。在乙醇丙酮介质中形成１∶１络合物，其λｍａｘ＝５２５ ｎｍ，吸光度与阿苯达唑浓度在０～２８０ ｍｇ／Ｌ范围内呈线性关系；表观摩尔吸光系数为８．０３×１０３Ｌ·ｍｏｌ－１·ｃｍ－１；桑德尔灵敏度为０．０３３ μｇ·ｃｍ－２；相对标准偏差小于１％（ｎ＝８），回收率符合要求。

奎宁与氯冉酸的胶束增敏荷移反应及其测定

提出了一种基于胶束增敏荷移反应测定奎宁的光度分析法。研究了在阳离子表面活性剂氯化十六烷基吡啶 (CPC)胶束体系中电子给体奎宁与电子受体氯冉酸之间的荷移反应产物的光谱性质。发现CPC对奎宁与氯冉酸的荷移反应络合物的光吸收有显著的增强作用 ,使络合物的表观摩尔吸光系数提高了 2 .5倍(λmax=5 2 0nm ,ε=3.6 4× 1 0 3 L·mol-1 ·cm-1 )。奎宁浓度在 2 0～ 80 0mg/L范围内符合比耳定律 ,r =0 9991。本方法用于片剂中奎宁含量的测定 ,其回收率为 97.3%～ 99.2 % ;5次测定的相对标准偏差为 1 .6 %～ 2 5 %。

氯冉酸为受体的荷移荧光光谱法测定洛美沙星

研究了电子受体氯冉酸与电子给体洛美沙星之间的荷移反应。实验结果表明 :在丙酮 甲醇介质中于室温下即可生成稳定的n π络合物 ,其荧光发射较洛美沙星有显著的增敏效应。研究并优化了影响反应的不同的条件和参数 ,据此建立了一种基于荷移反应简便可靠地测定洛美沙星的荧光光谱新方法 ,同时还研究了药物制剂的共存体的干扰 ,该方法已成功地用于纯品和制剂中洛美沙星含量的测定 ,其准确度和精密度令人满意。最低检出限为 0 0 4mg·L-1,回收率为 97 4 %～ 99 3% ,相对标准偏差为 1 3%～ 2 6 %。还对荷移反应的机理进行了探讨。

利用电荷迁移反应测定头孢羟氨苄

提出一种基于电荷迁移反应简便可靠地测定头孢羟氨苄的分光光度法。在甲醇－乙醇介质中，头孢羟氨苄与氯冉酸于５０℃反应１５ｍｉｎ能够形成稳定的１：１络合物，其λｍａｘ＝５２８ｎｍ，线性范围为２０～４００ｍｇ／Ｌ。用拟定的方法测定原粉和胶囊，结果与药典法一致。对浓度１００ｍｇ／Ｌ的药物１０次测定相对标准偏差为１．４％，样品的标准加入回收率为９９．０％～１００．８％。

荷移增敏分光光度法测定甲硝唑片中甲硝唑的含量

目的:建立用荷移增敏分光光度法测定甲硝唑片中甲硝唑含量的方法。方法:利用甲硝唑与氯冉酸在丙酮-氯代十六烷基吡啶(CPC)介质中形成稳定络合物,在513nm波长处测定络合物的吸光度。结果:甲硝唑浓度在12～250mg·L^(-1)范围内线性关系良好,相关系数(r)0.9994,检出限4.09mg·L^(-1),RSD为0.49%～1.26%(n=6),回收率99.0%～100.9%。结论:本法简便快速,条件易控制,测定结果与中国药典方法一致。

SBC法测定金花葵黄酮的含量

对金花葵植株各部分干花、果、叶、茎及金花葵产品酒、油中总黄酮含量进行了研究。以芦丁为标准品,采用新方法-硼氢化钠/氯醌(SBC)比色法对金花葵各样品总黄酮含量进行了测定,试验结果表明,金花葵植株各部分及产品中总黄酮含量在62.0 mg/g^229.0 mg/g之间,其中金花葵干花总黄酮含量最高,可达228.19 mg/g,为开发金花葵产品提供参考。

荷移荧光光谱法测定加替沙星

研究了加替沙星（GFLX）与电子受体四氯对苯醌（TCBQ）之间的荷移反应,建立了测定加替沙星的新方法。实验结果表明,在甲醇-水介质中于45℃水浴恒温20 min,GFLX与TCBQ可形成稳定的1∶1电荷转移络合物,其荧光发射强度较GFLX本身有显著的增强。在0.19-5.6 mg·L^-1浓度范围内,荧光强度与GFLX浓度呈良好的线性关系,检出限为0.005 6 mg·L^-1。用于药物制剂中GFLX的含量测定,其回收率为101.1%-103.9%;标准偏差为1.0%-1.9%。同时建立了测定尿样中GFLX的荷移同步荧光光谱法,GFLX浓度在0.023-3.4 mg·L^-1范围内与荧光强度呈良好的线性关系,检出限为0.003 4 mg·L^-1。用本方法测定尿液中的GFLX,结果与文献值基本一致,回收率为93.9%-101.0%;标准偏差为1.0%-1.7%。