具有不同类型桥基的双核Cu（Ⅱ）—Schiff碱配合物的合成 …

合成了３个分别以Ｃ２Ｏ＾２－４（「Ｃｕ２（Ｌ１）２（ｏｘ）」，１），ＡｃＯ＾－（「Ｃｕ２（ＡｃＯ）（Ｌ２）２」ＢＦ４，２）和酚氧（「Ｃｕ２９Ｌ３０２」（ＣｌＯ４）２，３）为桥基的双核铜配合物，并测定了１的复配合物「Ｃｕ２（Ｌ１）２（ｏｘ）」「Ｆｅ（ＯＨ）２（Ｈ２Ｏ）４」ＣｌＯ４．Ｈ２Ｏ及２和３的晶体结构。     

激光促进乙醇氧化偶联反应

用ＸＲＤ、ＩＲ和脉冲ＣＯ２激光，研究了在固体Ｃｕ２（ＰＯ４）（ＯＨ）ｔ Ｐｂ３（ＰＯ４）２表面上激光促进乙醇氧化偶联的反应性能。实验结果表明：乙醇的定位化学吸附态决定着反应产物的选择性，甲基吸附态（〉Ｐ＝０…Ｈ－ＣＨ２ＣＨ２ＯＨ）反应生成１，４－丁二醇，而羟基吸附态（〉Ｐｂ…ＯＨＣＨ２ＣＨ３）则生成乙烯；固体表面构造基元的振动结构是影响激光能量利用率的主要因素，Ｃｕ２（ＰＯ４）（ＯＨ）表面Ｐ＝Ｏ键     

CS_2在Cu－S键中插入产物（Ph_3P）_2Cu（S_2CSR）与溶剂反应的

ＣＳ_２在Ｃｕ－Ｓ键中插入产物（Ｐｈ_３Ｐ）_２Ｃｕ（Ｓ_２ＣＳＰｈ）与ＣＨ_２Ｃｌ_２－Ｃ_２Ｈ_５ＯＨ混合溶剂反应，获得单核铜配合物（Ｐｈ_３Ｐ）_２Ｃｕ（Ｓ_２ＣＯＯＣ_２Ｈ_５）和双核铜配合物（Ｐｈ_３Ｐ）_３Ｃｕ_２Ｃｌ_２等化合物晶体，用Ｘ－射线单晶衍射法测定前者的晶体结构。晶体的化学式为Ｃ_（３９）Ｈ_（３５）ＣｕＯＰ_２Ｓ_２，分子量为７０９．３，空间群Ｐ２１／ｎ，ａ＝９．３２９（６），ｂ＝１８．６６４（１１），ｃ＝２０，３４１（１３），β＝９５．５９（５）°，Ｖ＝３５２５（４）~３，Ｄ_ｃ＝１．３３７ｇ／ｃｍ~３，Ｚ＝４，Ｆ（０００）＝１４９２，μ＝０．８５２ｍｍ~（－１），Ｒ＝０．０４５。     

具有不同类型桥基的双核Cu(Ⅱ)-Schiff碱配合物的合成和晶体结构

合成了３个分别以Ｃ２Ｏ２－４（［Ｃｕ２（Ｌ１）２（ｏｘ）］，１），ＡｃＯ－（［Ｃｕ２（ＡｃＯ）（Ｌ２）２］ＢＦ４，２）和酚氧（［Ｃｕ２（Ｌ３）２］（ＣｌＯ４）２，３）为桥基的双核铜配合物，并测定了１的复配合物［Ｃｕ２（Ｌ１）２（ｏｘ）］·［Ｆｅ（ＯＨ）２（Ｈ２Ｏ）４］ＣｌＯ４·Ｈ２Ｏ（１′）及２和３的晶体结构．Ｘ射线衍射结果表明：１′，２和３分别属于Ｆｄｄｄ，Ｐ２１／ｃ和Ｐ２１／ｃ空间群．晶胞参数：［Ｃｕ２（Ｌ１）２（ｏｘ）］［Ｆｅ（ＯＨ）２（Ｈ２Ｏ）４］ＣｌＯ４·Ｈ２Ｏ，ａ＝２．４３９０（４）ｎｍ，ｂ＝３．０５３８（６）ｎｍ，ｃ＝１．８４９４（６）ｎｍ，α＝β＝γ＝９０．００°；２，ａ＝０．８４７（１）ｎｍ，ｂ＝２．６５４２（８）ｎｍ，ｃ＝１．４１００（６）ｎｍ，β＝９１．３４（６）°；３，ａ＝０．７６４６（３）ｎｍ，ｂ＝１．６９８３（３）ｎｍ，ｃ＝２．４４１７（３）ｎｍ，β＝９７．１１°     

用HGAA法和DANMF法测定血清和猪肝中硒

以ＨＮＯ３－ＨＣｌＯ４消化试样，用Ｈ２Ｏ２还原Ｓｅ（Ⅵ）至Ｓｅ（Ⅳ）后，以氢化物原子吸收法和２，３二氢基萘荧光法分别测定了血清和猪肝中总硒。试验表明，两种方法有相当的检出限、准确度和精确度。对猪肝标样ＧＢＷ０８５５１和血清样的分析，方法的ＲＳＤ（ｎ＝５）猪肝样为４％，血清样为２％。     

CuO／γ－Al_2O_3中热稳定助剂作用的探讨

用等量共浸法和分浸法制备了含Ｃａ、Ｓｒ、Ｂａ、Ｍｇ、Ｚｒ和Ｌａ助剂的ＣｕＯ／γ－Ａｌ_２Ｏ_３催化剂（ＣｕＯ／Ａｌ_２Ｏ_３＝８ｗｔ％，Ｍ／Ｃｕ（原子比）＝０．１５，Ｌａ／Ｃｕ＝０．３５）．用ＸＲＤ和ＸＰＳ等考察了在高温７５０℃、９５０℃和１０５０℃老化后的相结构和ＣＯ氧化活性，实验表明所有助剂均有不同程度的抗烧结和抗相变作用。其中Ｌａ、Ｃａ和Ｚｒ的效果最好。分浸法比共浸法好。在９５０℃老化后，ＣｕＡｌ_２Ｏ_４和α－Ａｌ_２Ｏ_３同步产生；随老化温度增高，ＣＯ氧化活性有所下降。分浸法制备的含Ｚｒ样品在９５０℃老化后活性最高。从γ－Ａｌ_２Ｏ_３缺陷尖晶石特征及高温脱结构水过程，探讨了助剂抑制α－Ａｌ_２Ｏ_３生成的原因。     

（Cu（C14H11O3）（C10H8N2）2NO3.C2H5OH的合成,晶体结构和红外光谱

合成了（Ｃｕ（Ｃ１４Ｈ１１ｏ３）（Ｃ１０Ｈ８Ｎ２）ＮＯ３．Ｃ２Ｈ５ＯＨ化合物并测定其晶体结构，晶体属Ｐ空间群，ａ＝１．１９１１（２）ｎｍ，ｂ＝１．５３２２（２）ｎｍ，ｃ＝１．０４９２（２）ｎｍ，ａ＝１０８．９８（１）°β＝１０７．０４（１）°，γ＝７０．２５（１）°Ｚ＝２．在（Ｃｕ（Ｃ１４Ｈ１１Ｏ３）（Ｃ１０Ｈ８Ｎ２）２）配合阳离子中，２个２．２’－联吡啶的４个氮原子和二苯羟乙酸的１个羟基氧原子位     

甲烷部分氧化制合成气Ⅳ．镍铜催化剂的反应性能及影响因素的考察

对镍铜甲烷部分氧化催化剂的制备化学研究表明，在Ａｌ２Ｏ３、ＳｉＯ２、ＭｇＯ、ＴｉＯ２、Ｙ型分子筛等载体中，具有较好氢溢流功能的Ａｌ２Ｏ３所担载的镍铜催化剂，有最佳的反应性能，载体的产物溢流功能对反应中合成气的生成是有利的．对于ＮｉＯ－ＣｕＯ－Ａｌ２Ｏ３催化剂，组分Ｃｕ的最佳含量是Ｃｕ／Ａｌ＝０．２／４（原子比），Ｎｉ／Ａｌ（原子比）在１／４－１．５／４范围内催化剂均保持最佳的反应性能，此时，甲烷转化率为９８．１％，对ＣＯ、Ｈ２的选择性分别达９７％、１００％．制备方法对催化性能影响的结果显示，以（ＮＨ４）２ＣＯ３为沉淀剂的共沉淀法，是制备ＮｉＯ－ＣｕＯ－Ａｌ２Ｏ３催化剂的最佳方法．ＮｉＯ－ＣｕＯ－Ａｌ２Ｏ３催化剂的甲烷部分氧化性能在４００－５００℃间有一突跃，并在７００℃时达到最佳值；过高的反应气空速对ＣＯ、Ｈ２的选择性是不利的     

以PMBP为萃取剂和化学改进剂/电热蒸发电感耦合等离子体原子发射光谱测定二氧化锆中痕量铕

提出了用β－二酮类试剂１－苯基－３－甲基－４苯甲酰基－吡唑酮［５］（ＰＭＢＰ）为萃取剂和 化学改进剂的电热蒸发电感耦合等离子体原子发射光谱（ＥＴＶ—ＩＣＰ—ＡＥＳ）测定高纯ＺｒＯ２ 中痕量Ｅｕ的新方法。讨论了影响Ｅｕ－ＰＭＢＰ 螯合物蒸发的主要因素。在优化实验条件下，Ｅｕ 的检出限为０．９μｇ／Ｌ，相对标准偏差为３．４％，试样分析的回收率为９４．５％～１０５．２％．     

μ—4,4‘—联吡啶桥联三核Cu（Ⅱ）配合物的合成和磁性

合成了３种以４，４’－联吡啶为配体的三核环状Ｃｕ（Ⅱ）配合物［Ｃｕ３（４，４＇－ｂｐｙ）３．（ｐｈｅｎ）３］（ＣｌＯ４）６．２Ｈ２Ｏ（１），［Ｃｕ３（４，４＇－ｂｐｙ），（ｂｐｙ）３］（ＣｌＯ４）６．Ｈ２Ｏ（２）和［Ｃｕ３９４，４＇－ｂｐｙ）３．（ＮＯ２－ｐｈｅｎ）３］（ＣｌＯ４）６．６Ｈ２Ｏ（３）。经元素分析，电导，ＩＲ，电子光谱，ＥＳＲ，磁化率等方法进行了表征，推定该配合物具有以４，４’－联吡     

Spectrophotometric determination of tannins in tea and beer samples with iron(III) and 1,10-phenanthroline as reagents

A simple and accurate spectrophotometric method is proposed for the determination of tannins in tea and beer samples based on the reduction of iron(III) to iron(II) by tannins at 80 degrees C for 20 min. The iron(II) was then reacted with 1,10-phenanthroline at pH 4.4 to form a coloured complex. Background correction could be effected by precipitating the tannins in the sample solution twice with gelatin and kaolin. Absorbance measurements were made at 540 nm and the calibration graph was linear from 0 to 5.5 micrograms ml-1 of tannic acid with a slope of 0.213 A p.p.m.-1. The precision for the determination of tannins in a tea sample containing 9.45% of tannins was 1.8%. Most of the ingredients commonly found in tea and beer samples do not interfere with the determination. Several tea and beer samples were analysed for their tannin content using the proposed method.     

A colorimetric method for the determination of tannins in tea

Summary A colorimetric method for the estimation of tannins in green leaf and black tea is described. The absorbance corresponding to tannins and other oxidizable substances is read at 760 nm, the Folin-Denis reagent being used. The absorbance corresponding to non-tannins is read after precipitation of the tannins with gelatine. The tannin content of the tea is calculated by difference.

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Zusammenfassung Ein colorimetrisches Verfahren zur Tanninbestimmung in grünem und schwarzem Tee wurde beschrieben. Die den Tanninen und anderen oxydierbaren Substanzen entsprechende Extinktion nach Anwendung des Reagens von Folin-Denis wird bei 760 nm abgelesen. Die dem Nicht-Tannin entsprechenden Werte werden nach Fällung der Tannine mit Gelatine bestimmt. Der Tanningehalt wird dann aus der Differenz ermittelt.

     

Spectrofluorimetric determination of tannins based on their activative effect on the Cu(II) catalytic oxidation of rhodamine 6G by hydrogen peroxide

A simple and highly sensitive kinetic fluorimetric method is proposed for the determination of trace tannins, based on the activation of tannins on the oxidation of rhodamine 6G (Rh 6G) by hydrogen peroxide catalyzed by Cu(II) ion. The calibration graph was rectilinear in the range 0.08-1.28 mg l⁻¹ for tannin, the 3σ detection limit for tannin is 0.0455 mg l⁻¹. The relative standard deviation for 11 determinations of 0.4 mg l⁻¹ tannin is 0.96%. The proposed method has been successfully used to determine tannins in tea and Chinese gall. The results obtained were compared with those provided by the Folin-Ciocalteu method. This is the first procedure to be reported for the determination of tannins based on fluorimetric measurements.     

Selective determination of aluminum bound with tannin in tea infusion.

In this study, an analytical method for indirect measurement of Al bound with tannin in tea infusion was studied. This method utilizes the ability of the tannins to precipitate with protein. Separation conditions were investigated using model solutions. This method is uncomplicated, inexpensive and suitable for real samples. About 34% of the total Al in brew extracted from commercially available teas was bound to condensed and hydrolyzable tannins.     

Determination of tannins in tea by potentiometry and atomic absorption spectrometry

Summary Different alternatives for the determination of tannins in tea with Cu ionspecific electrodes and atomic absorption spectrometry are discussed. The methods are based on the precipitation of tannins with copper acetate. A screening of methods is carried out in three successive steps: determination of (1) Cu in a simple aqueous solution, (2) tannic acid in aqueous solution and (3) tannins in tea. Two procedures are proposed as suitable tools for tannin determination in tea, i.e. direct potentiometry of excess Cu²⁺ and AAS, the first being the easiest and most rapid.

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Bestimmung von Tanninen in Tee durch Potentiometrie und Atomabsorptions-Spektrometrie

Zusammenfassung Verschiedene Möglichkeiten zur Bestimmung von Tanninen in Tee mit Hilfe einer kupferionenselektiven Elektrode sowie der AAS werden diskutiert. Die Methoden beruhen auf der Tanninfällung mit Kupferacetat. Im einzelnen wurden folgende Stufen untersucht: Kupferbestimmung in wäßriger Lösung, Gerbsäurebestimmung in wäßriger Lösung, Tanninbestimmung in Tee. Sowohl die potentiometrische Bestimmung des Kupferüberschusses bei der Fällung als auch die AAS-Bestimmung haben sich als geeignet erwiesen, wobei erstere als das einfachste und schnellste Verfahren empfohlen wird.

     

Spectrofluorimetric Determination of Cu2＋ Using New Fluorogenic Reagent

A new synthesized fluorogenic reagent,8-[(2-pyridine)methylideneamino] quinoline (PMAQ), was utilized for spectrofluorimetric determination of Cu(II) at trace levels. PMAQ, a good fluorogenic reagent, though insoluble in water, but is soluble in ethanol and 20% ethanol-water. The excitation and the fluorescence wavelengths of PMAQ were 310 and 434 nm respectively. When the reagent was complexed with Cu(II), the fluorescence intensity decreased proportionally with the concentration of Cu(II) at pH 4.5 by a static quenching effect. The highest sensitivity to Cu^2＋ determination was shown to be at PMAQ concentration of 1.0×10^－5mol•L^－1. In order to enhance the quenching effect, the Cu(II)-PMAQ complex solution was kept at 22 ℃ for 20 min. Though the interferences by Co(II) and Fe(III) were very serious, they were however, completely eliminated by being masked with oxalate and ascorbate ions respectively. The linear dynamic range for Cu(II) determination was between 25—441 µg•L^－1 with the detection limit of 18 µg•L^－1 (RSD＝3.7%, n＝6). The proposed method was successfully applied to the determination of Cu(II) in real samples including human blood serum, commercial tea and wheat flour.     

Electrothermal vaporization in inductively coupled plasma atomic emission spectrometry for direct multielement analysis of food samples with slurry sampling

Slurry sampling followed by electrothermal vaporization (ETV) was used as sample introduction technique in inductively coupled plasma atomic emission spectrometry (ICP-AES) for the direct determination of trace elements in food samples. A polytetrafluoroethylene (PTFE) emulsion was used as a fluorinating reagent to promote vaporization and the transportation of analytes. The main factors affecting the analytical signals were investigated in detail. Under optimum operating conditions, the detection limits (DL) for this method varied from 1.8 (Cu) to 215 ng/mL (Zn), while the relative standard deviations (RSD) were in the range 2.6% (Cu)-7.2% (Zn). The proposed method was successfully applied to the direct determination of trace amounts of V, Cu, Cr, Fe, Zn, and La in rice without any chemical pretreatment. The precision was evaluated by analyzing a standard reference material (tea leaves, GBW 07605) and comparing the results from this method with results obtained by pneumatic nebulization (PN) ICP-AES after the wet-chemical decomposition of the same sample.From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 3, 2005, pp. 286–290.Original English Text Copyright © 2005 by Chen.This article was submitted by the author in English.     

Utilization of tetrazolium blue for the colorimetric assay of tannins in tea

A simple, rapid and accurate colorimetric method is proposed for the determination of tannins, based on the reduction of tetrazolium blue in alkaline medium by tannins at 90 ± 2 °C for 15 min, leading to the formation of a highly coloured formazan derivative. Absorbance measurements were made at 527 nm and the calibration graph was linear for 0.2-9.0 g/ml of tannic acid. For more accurate analysis, the Ringbom optimum concentration range was found to be 0.5–8.2 g/ml. The relative standard deviation for the determination in a tea sample containing 7.55% tannins was 1.65%. Most of the ingredients commonly found in tea samples do not interfere with the determination. Several tea samples were analysed using the proposed method.     

基质辅助激光解吸附飞行时间质谱分析缩合单宁的阳离子化问题

以单价金属离子Cs 和Na 作为离子化试剂,对3种缩合单宁进行基质辅助激光解吸附飞行时间(MALD I-TOF)质谱分析。加入Na 作为阳离子化试剂,能得到较高质量的质谱图。但由于实验通道中几乎不可能完全去除的K 的干扰而会高估棓儿茶酚/表棓儿茶酚单元的组成比例,从而影响对棓儿茶酚/表棓儿茶酚单元存在与否的判断;选择Cs 作为阳离子化试剂可以避免此问题,但在复杂的缩合单宁分析中,同样因为杂质离子Na 和K 的干扰而使得质谱图变得更复杂;未去离子处理直接对缩合单宁进行MALD I-TOF质谱分析与去离子并加入Cs 的处理比去离子并加入Na 能检测到更高聚合度的高聚物,检测到离子峰强度最高的聚合物随离子不同而不同。     

Electrochemical Determination of Tannins Using Multiwall Carbon Nanotubes Modified Glassy Carbon Electrode

A novel chemically modified electrode is prepared on the basis of the attachment of multiwall carbon nanotubes (MWNTs) to the surface of a glassy carbon electrode (GCE) in the presence of a hydrophobic surfactant. The electrochemical behavior of tannins at the MWNTs-modified GCE is investigated. Tannins yield a well-defined oxidation at about 0.30 V (SCE) at the MWNTs-modified GCE. MWNT-film shows remarkable enhancement effect on the oxidation peak current of tannins. The experimental parameters are optimized, and a direct electrochemical method to detect tannins is proposed. The oxidation peak current is proportional to the concentration of tannins over the range from 4 × 10^–7 to 2 × 10^–4 M, and the detection limit is 1 × 10^–7 mol/l after 5 min of accumulation. The relative standard deviation of 6% for determination of 2 × 10^–6 mol/l tannins indicates excellent reproducibility. The analysis method is demonstrated by using tea and Chinese gall samples.