巯基棉分离-萃取分光光度法测定水中痕量硒(Ⅳ)

1引言在0．5mol／L的盐酸介质中用流基棉富集水中硒（IV），解吸后用一种新的革取分光光度法测定之。本法是基于硒（IV）将1离子氧化为h，h和结晶紫分子形成的配位物又被二甲苯革取，此法检测下限可达0．5pg／Lo2实验部分2．王主要仪器和试剂UVIKON810／820双光束分光光度计和UV－120型分光光度计；硒标准液用高纯硒粉配制，其它所用试剂皆为分析纯；流基根参照有关资料制备。2．2实验方法将处理过的流基梯用水冲入直径06cm的玻璃管中，水样1000mL加40mL浓盐酸后使其自然从含流基棉玻璃管中流过，流速为2mL／min，解吸时往妩基棉中加…     

硅藻土TBP反相萃取层析法连续分离钼和锗

研究了以6mol/L盐酸做流动相，以负载有磷酸三丁酯（TBP）的硅烷化白色担体做固定相，反相萃取层析法连续分离Ge和Mo与其它干扰高子如W、Sb、Fe等的分离条件。方法可将Ge、Mo与W、Sb、Fe、Sn等完全分离，并已应用于中草药中微量锗和钼的分离。     

溶剂萃取动力学的研究 Ⅱ.三辛基氧化膦从盐酸体系中萃取铀(Ⅳ)的速率

本文采用上升液滴法,研究了三辛基氧化膦(TOPO)-环己烷溶液从盐酸体系中萃取U(IV)的动力学.按实验结果在一定的盐酸浓度下,TOPO箤取U(IV)的速率可由下述萃取动力学方程式表示:R=K[U(IV)][TOPO]_(0)在[HCl]=3M和15℃时,计算得萃取速率常数K=3.7x10~(-5).在不同盐酸浓度的溶液中,TOPO萃取U(IV)的速率与盐酸浓度的3/2次方成正比.测定了温度(15～45℃)对萃取速率的影响,求得萃取反应的表观活化能为10.8 kcal/mol. 由实验结果推测,TOPO从盐酸体系中萃取U(IV)的反应可能按下列两步进行:UCl_4+TOPO_(0)=UCl_4·TOPO_(0) (1)UCl_4·TOPO_(0)+TOPO_(0)=UCl_4·2TOPO_(0) (2)而生成界面溶剂配合物的反应(1)是萃取速率的控制步骤.     

萃取-缝管原子捕集原子吸收法测定水中碲(Ⅳ)和碲(Ⅵ)

研究了碲（Ⅳ）和碲（Ⅵ）在 DDTC-CCI．体系中的萃取和反萃取行为，并用缝管原子 捕集技术结合火焰原子吸收法测定了水样中的碲（Ⅳ）和碲（Ⅵ），特征浓度为1.2 μg／L／1％ 吸收，检出限0.2μg/L，相对标准偏差1．7％，富集倍数可达100倍。     

反相萃取层析与光度法联用分离/测定中草药中微量铁的研究

研究了硅藻土-TBP反相萃取层析-分光光度法分离和测定微量铁的新方法.以0.30mol/L盐酸做流动相,以负载有磷酸三丁酯(TBP)的硅烷化白色担体为固定相,反相萃取层析法分离微量Fe(Ⅲ)与Co(Ⅲ)、Ge(Ⅳ)、Al(Ⅲ)、Cr(Ⅲ)、Mn(Ⅱ)、Ni(Ⅱ)等.在4.0mol/L盐酸介质中,铁与多种金属离子都被萃取在TBP柱上.用2mol/L盐酸洗脱部分离子,用0.30mol/L盐酸可定量地洗脱铁,然后用0.010mol/L盐酸可将柱上的其它离子洗脱.洗脱液中的铁用分光光度法测定.此方法可将铁与绝大部分干扰离子分离,并用于中草药中微量铁的分离和测定.     

流动注射在线富集分离-火焰原子吸收光谱法测定水体中的铬(Ⅲ)和铬(Ⅵ)

内装活性氧化铝（碱式）和阴离子交换树脂的微型柱流动注射在线富集分离水体中的铬（Ⅲ）和铬（Ⅵ），火焰原子吸收法直接检测。微型住可同时富集两种价态的离子，分别用1mol／L的NH4NO3和HNO3洗脱Cr（Ⅵ）和Cr（Ⅲ）于喷雾器中。进样时间25s，铬（Ⅵ）和铬（Ⅲ）的富集倍数分别为11倍和20倍，实际水样的加标回收率在90％～106％之间；分析速率为50个样／h；铬（Ⅵ）、铬（Ⅲ）的检出限（3δ）分别为1．5μg／L和0．7μg／L；相对标准偏差（50μg／L）分别为1．9％和2．6％。     

钼(Ⅵ)-向红菲啰啉络合物的吸附伏安行为

在 PH=4．0的 0．3 mol/L的 HAc－NaAc介质中，钼（Ⅵ）-向红菲啰啉体系在悬汞电极上，于-0．58 V（vs．SCE）电位处得到钼（Ⅵ）-向红菲啰啉络合物的吸附还原波，其1.5次微分伏安图的峰峰值epp与Mo（Ⅵ）在3．0X10-10”～1．2X10-7mol／L浓度范围内呈良好的线性关系，检测限可达8×10-11mol／LMo（Ⅵ）．方法用于豆类样品中微量钼的测定，结果较好。     

气相色谱-质谱法测定肝脏组织中盐酸克伦特罗和盐酸菜克多巴胺

建立了同时测定动物肝组织中盐酸克伦特罗和盐酸莱克多巴胺残留量的固相萃取-气相色谱-质谱分析方法。动物肝组织样品在碱化的条件下用乙酸乙酯和异丙醇混合溶剂提取，提取液浓缩后用乙酸乙酯溶解，然后再用稀盐酸反萃取去除脂肪，调pH值后经SCX固相萃取（SPE）柱净化，洗脱液经氮气吹干后经双三甲基硅基三氟乙酰氨（BSTFA）衍生，采用选择离子模式（盐酸克伦特罗：86、212、262、277，盐酸莱克多巴胺：163、192、234、250）进行测定，外标法定量。盐酸克伦特罗和盐酸莱克多巴胺的检出限分别为0．30和1．00μg／kg。盐酸克伦特罗添加浓度在1．0～5．0μg／kg范围内，添加回收率为77．4％～88．3％；相对标准偏差（RSD）为3．1％～5．1％；盐酸莱克多巴胺添加浓度在4．0～20．0μg／kg，添加回收率为69．8％～82．1％；相对标准偏差（RSD）为3．5％～4．9％；衍生物的峰面积与被测物浓度分别在0．003～1．00mg／L和0．012～4．00mg／L范围内呈良好的线性关系，线性回归系数均大于0．999。     

铟(Ⅲ)-茜素红体系的吸附伏安法

本文对铟（Ⅲ）与茜素红络合物在悬汞电极上的吸附伏安法作了研究，确定了电极过程．在HAc－NaAc（PH4．92）缓冲溶液中有菌素红存在下，用1．5阶微分吸附伏安法测定铟，其线性范围是1×10－10～8×10－8mol／L，检测限5×10－11mol／L，用此法测定了化探样中痕量铟，结果良好。     

原子荧光光谱法分析煤中的锗

将Ge含量在10～50 ng/mL的Ge标准溶液转化为GeCl4后用CCl4两次萃取1次纯水反萃取,用原子荧光光谱法测定,Ge的回收率在97.2%以上,标准工作曲线的相关系数达0.999以上.在处理试样时,用HF-HNO3-HClO4于高压消化罐内处理煤试样,再经CCl4经两次萃取1次纯水反萃取具有试剂用量少、试样处理简单、锗损失率低、干扰小的特点,其RSD在2.2%～3.7%之间,锗的加标回收率在97.6%～101.2%之间.     

A novel catalytic adsorptive stripping voltammetric method for the determination of germanium ultratraces in the presence of chloranilic acid and the V(IV)·HEDTA complex

A novel, sensitive catalytic adsorptive stripping voltammetric procedure which can be used to determine trace amounts of germanium is described. The method is based on the interfacial accumulation of the complex formed by Ge(IV) and the product of the reduction of chloranilic acid on the hanging mercury drop electrode or the renewable silver amalgam film electrode, and its subsequent reduction from the adsorbed state followed by the catalytic action of the V(IV)·HEDTA complex. The presence of V(IV)·HEDTA greatly enhances the adsorptive stripping response of Ge. The reduction of the Ge(IV) in the presence of chloranilic acid and V(IV)·HEDTA was investigated in detail and the effects of pH, electrolyte composition, and instrumental parameters were studied. Under optimal conditions, the catalytic peak current of germanium exhibited good linearity for Ge(IV) concentrations in the range of 0.75–60 nM (for 60 s of accumulation at −0.1 V, r² = 0.995) and a low limit of detection (LOD = 0.085 nM). The procedure was successfully applied to determine Ge in water samples.

     

Anodic stripping voltammetry of germanium at the hanging mercury drop electrode

The Ge(IV)—Ge(0) system was investigated by cyclic and stripping voltammetry at HMDE in acidic pyrogallol medium and in phosphate, borate and carbonate buffers. It was found that germanium electrodeposited from dilute Ge(IV) solutions dissolved anodically forming two peaks corresponding to the oxidation of the unstable homogeneous and stable heterogeneous amalgams. Both peaks can be exploited analytically for the determination of traces of germanium but due to the complex nature of the germanium amalgam the sensitivity and reproducibility of the determinations are lower compared to the results obtained for metals well-soluble in mercury.     

Square-wave voltammetry of the o-catechol-Ge(IV) catalytic system after adsorptive preconcentration at a hanging mercury drop electrode

Square-wave (SW) voltammetry in connection with a hanging mercury drop electrode has been applied for studying the reduction of Ge(IV) catalyzed by o-catechol after adsorptive preconcentration. Acetate buffer solutions with low and high analytical concentrations of o-catechol [with respect to that of Ge(IV)] have been used. Dependences of SW catalytic peaks on accumulation conditions have been attributed to the formation of the catalytic complexes via a direct-adsorption mechanism. The nature of the electrocatalytic process (involving an apparently quasi-reversible electrode reaction with an adsorbed reactant and a diffusing product) allows us to explain complex dependences of catalytic peaks on SW-parameters. Adequate conditions for determination of o-catechol and Ge(IV) by means of SW catalytic adsorptive voltammetry have been established.     

2,3,7-Trihydroxyfluorones immobilized on cellulose matrices in test methods for determining rare elements

It was shown that 2,3,7-trihydroxyfluorones immobilized by adsorption on cellulose matrices can be used as reagents for the test determination of Mo(VI), Ti(IV), Ge(IV), Hf(IV), Nb(V), Ta(V), W(VI), Bi(III), V(IV), and Zr(IV). The change of the protolytic and complexing properties of trihydroxyfluorones immobilized on cellulose matrices was considered in comparison to corresponding properties in a solution. It was found that the reactions of trihydroxyfluorones with rare elements on cellulose matrices and in a solution exhibit similar effects upon the addition of cetylpyridinium. These effects are the bathochromic shift of the absorption maxima of the reagents and their complexes with analytes and the extension of the range of optimum acidity for complex formation. The complexation of salicylfluorones with the titanium(IV) in solution and on cellulose paper was studied by IR spectrometry. Phenylfluorone immobilized on a mixed-fiber cloth as used in test determinations of (mg/L) 0.05–5 Ti(IV), V(IV), Hf(IV), Nb(V), and Mo(VI); 0.01–5 Ge(IV) and Zr(IV); 0.05–1 Bi(III) and W(VI); and 0.1–5 Ta(V) by the color intensity of the indicator matrix after passing through 20 mL of a test solution. It was shown that phenylfluorone immobilized on cellulose paper can be used to determine (mg/L) 0.05–50 Ti(IV), 0.5–1000 Ge(IV), 0.5–500 Zr(IV), 5–200 Bi(III), 0.1–50 Mo(VI), 0.1–1000 V(IV), 0.1–100 Nb(V), 0.1–800 Hf(IV), 1–100 Ta(V), and 1–800 W(VI) by the length of the colored zone of a test strip after it was brought into contact with a test solution.     

Determination of germanium by potentiometric stripping analysis and adsorption potentiometric stripping analysis

Potentiometric stripping analysis was applied to determination of germanium(IV) in 0.2M NH₃-NH₄Cl (pH 8.4) buffer solution at −1.8 V (vs. Ag/AgCl), with dissolved oxygen or Hg(II) as oxidant. The sensitivity was 8.5 × 10⁻⁹M in the presence of 2.0 × 10⁻⁵M Hg(II) with plating for 15 min after deaeration for 20 min. Cyclic voltammetry revealed that GE(IV) å Ge at the surface of the mercury-film electrode in a one-step irreversible reduction reaction, and the Ge at the electrode was oxidized by dissolved oxygen in the solution. The presence of complexing agents such as Alizarin Red (ARS), which forms a Ge(IV) complex adsorbed at the electrode, improved the sensitivity by one order of magnitude. The presence of adsorption was revealed by the temperature coefficient, the electrocapillary curve and cyclic voltammetry. Ge-containing samples were analysed by the proposed methods and agreement with the results obtained by other methods was excellent.     

Reversible oxidation state change in germanium(tetraphenylporphyrin) induced by a dative ligand: aromatic GeII(TPP) and antiaromatic GeIV(TPP)(pyridine)2

Treatment of GeCl2(dioxane) with Li2(TPP)(OEt2)2 (TPP = tetraphenylporphyrin) in THF yields Ge(TPP), the first free Ge(II) porphyrin complex. In pyridine Ge(TPP) is converted to Ge(TPP)(py)2, an antiaromatic Ge(IV) complex, whereas in benzene the reaction is reversed, and pyridine dissociates from Ge(TPP)(py)2 to form Ge(TPP). That reversible reaction represents an unusual, if not unique, example of an oxidation-state change in a metal induced by coordination of a dative ligand. UV-vis and 1H NMR spectroscopy show that Ge(TPP) is an aromatic Ge(II) porphyrin complex, while the 1H NMR spectrum of Ge(TPP)(py)2 clearly indicates the presence of a strong paratropic ring current, characteristic of an antiaromatic compound. Both Ge(TPP) and Ge(TPP)(py)2 have been crystallographically characterized, and the antiaromaticity of Ge(TPP)(py)2 leads to alternating short and long C-C bonds along the 20-carbon periphery of its porphine ring system. Coordination of pyridine to Ge(TPP) greatly increases its reducing ability: the Ge(TPP)0/2+ redox potential is about +0.2 V, while the Ge(TPP)(py)2(0/+) redox potential is -1.24 V (both vs. ferrocene). The equilibrium constant of the reaction Ge(TPP) + 2 py = Ge(TPP)(py)2 in C6D6 is 22 M-2. The germanium complex of the more electron-withdrawing tetrakis[3,5-bis(trifluoromethyl)phenyl]porphyrin, Ge(TArFP), and its pyridine adduct Ge(TArFP)(py)2 were synthesized. The equilibrium constant of the reaction Ge(TArFP) + 2 py = Ge(TArFP)(py)2 in C6F6/C6D6 is 2.3 x 10(4) M-2. Density functional theory calculations are consistent with the experimental observation that M(TPP)(py)2 formation from M(TPP) and pyridine is most favorable for M=Si, borderline for Ge, and unfavorable for Sn.     

Synthesis and structures of an unusual germanium(II) calix[4]arene complex and the first germanium(II) calix[8]arene complex and their reactivity with diiron nonacarbonyl

The protonolysis reaction of the germanium(II) amide Ge[N(SiMe3)2]2 with calix[4]arene and calix[8]arene furnishes the two germanium(II) calixarene complexes {calix[4]}Ge2 and {calix[8]}Ge4, respectively, which have been crystallographically characterized. The calix[4]arene complex contains a Ge2O2 rhombus at the center of the molecule and is one of the only four germanium(II) calix[4]arenes that have been structurally characterized. The calix[8]arene species is the first reported germanium calix[8]arene complex, and it exhibits an overall bowl-shaped structure which contains two Ge2O2 fragments. The latter complex reacts with Fe2(CO)9 to yield an octairon compound, which has also been structurally characterized and contains four GeFe2 triangles arranged around the macrocyclic ring. The germanium(II) centers are oxidized to germanium(IV) in this process, with concomitant reduction of the neutral diiron species to Fe2(CO)(8)2- anions.     

Some electroanalytical aspects of using pulse polarography for determination of Ge(IV)

Summary Presented data give some informations of analytical importance as a result of pulse polarographic investigations of Ge(IV) in KCl solutions within pH range 3–12 at Ge concentration from 1×10^–4 to 2.5×10^–6 M. It was shown that Ge(IV) can be polarographically active in acidic solution but its reduction interferes with hydrogen gas development. The addition ofp-quinone enables the determination of Ge(IV) without this interfering effect.Suggested explanation of the observed changes in polarographic curves dependent on pH and Ge concentration based on the existence of several polarographically active forms.

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Elektroanalytische Bemerkungen zur pulspolarographischen Bestimmung von Ge(IV)

Zusammenfassung Unsere Ergebnisse bieten einige Informationen über die pulspolarographische Bestimmung von Ge(IV) in KCl-Lösungen innerhalb pH 3–12 und bei Ge-Konzentrationen zwischen 10^–4 und 2,5×10^–6 M. Es wurde gezeigt, daß Ge(IV) in saurer Lösung polarographisch aktiv ist, seine Reduktion aber durch Wasserstoff-Entwicklung gestört wird. Der Zusatz vonp-Chinon beseitigt diese Störung. Die Änderung der polarographischen Kurven je nach Ge-Konzentration und pH beruht vermutlich auf der Existenz verschiedener polarographisch aktiver Formen.

     

Spectrophotometric determination of germanium with Catechol Violet and cetyltrimethylammonium bromide

A ternary complex between germanium, Catechol Violet (CV) and cetyltrimethylanunoniuni bromide is proposed for the determination of germanium. The stoichiometric ratio Ge:CV is 1:2. Beer's law is obeyed from 0.1 to 1.0 ppm of Ge. The method is highly selective. Interference from Sn(IV), Fe(III), Bi(III), Cr(VI), Mo(VI), V(V) and Sb(III) in mg amounts is eliminated by extracting the germanium into carbon tetrachloride from 9M HC1 and then stripping into water before the photometric determination.     

Nephelometric determination of germanium(IV) witho-phenanthroline and bromopyrogallol red in the presence of triton X-100

The light scattering of germanium(IV) witho-phenanthroline [phen] and bromopyrogallol red [BPR] in the presence of Triton X-100 has been studied. The ternary complex shows a constant light scattering intensity in an acidic medium (0.02 mol/l HCl+0.02 mol/l H₃PO₄). The maximum wavelength was 332 nm. The calibration graph is linear in the range 0.03–10 g/25 ml for Ge(IV). The detection limit is 0.03 g/25 ml. The composition of the ternary complex is GephenBPR = 122. The effects of diverse ions on the determination of Ge(IV) were examined. This simple method with high sensitivity can be successfully applied to the determination of Ge(IV) in coal fly ash, with a relative standard deviation of 2%.