ICP-AES法测定镀铝锌(锌铝)合金彩涂板镀层中的铝锌硅镁镧铈

采用控温加热法退除涂层,用100g LNaOH溶液溶解镀层,研究了共存元素间干扰和酸度效应,建立了ICP AES法测定镀铝锌(锌铝)合金彩涂板镀层中Al、Zn、Si、Mg、La、Ce的方法,检出限(3σ)分别为19.8、2.4、6.3、0.3、4.6、7.6ng mL,相对标准偏差为0.2%～0.6%,回收率为99.3%～104.6%。     

ICP-AES法测定镀铝锌钢板镀层中的铝含量

用50g/L的氢氧化钠溶液溶解镀铝锌钢板镀层,以盐酸溶液(1 4)进行酸化,采用ICP?AES法测定两种镀铝锌钢板镀层中的铝含量,测定结果的相对标准偏差分别为2.3%和1.4%(n=11),回收率为94.8%～98.5%。对两种镀铝锌钢板金属中铝含量测定结果的不确定度进行了评定,分别为0.10%(铝含量为4.82%)、0.9%(铝含量为54.3%)。     

ICP—AES法同时快速测定镀铝锌薄板镀层中铝和锌

镀铝锌钢板的防锈能力一般为传统镀锌钢板的四倍以上。生产厂家要求将样品完全溶出其表面镀层铝锌等合金,同时最大限度地不溶出基钢,并测定溶出镀层合金中铝和锌的质量分数。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定人发中铜、锌、钙、镁、铁

样品经硝酸-高氯酸消化溶解,高氯酸冒烟,盐酸溶解盐类后,在盐酸(5%)介质中,在选定的测定条件下,用电感耦合等离子体原子发射光谱(ICP-AES)法测定人发中微量元素铜、锌、铁、镁、钙。选择Cu 327.3、Zn 206.2、Fe 238.2、Mg 279.5、Ca 315.8nm分别作为铜、锌、铁、镁、钙的分析线与混合标准溶液同时测定;方法加标回收率为98.6%～101%,铜、锌、铁、镁、钙的精密度(RSD,n=8)为0.37%～2%,准确度(RE)为-3.4%～1.15%,检出限分别为0.002 3、0.001 6、0.004 6、0.003 0、0.001 4μg/mL。方法克服了分光光度法和原子吸收光谱法操作繁琐、周期长、成本高、灵敏度低等缺点。用于测定人发样品中的铜、锌、铁、镁、钙元素,测定结果与原子吸收光谱法测定值基本一致。经GBWO7061标准物质和自制标样分析验证,测定值与标准值吻合,结果准确可靠。     

硝酸钠-硫氰酸铵-溴化十六烷基吡啶液-固体系浮选分离锌(Ⅱ)

研究了硝酸钠-硫氰酸铵-溴化十六烷基吡啶液-固体系浮选分离测定锌(Ⅱ)的行为及其在食品分析中的应用。结果表明,当固体NaNO3用量为1.0 g,0.25 mol/L硫氰酸铵和0.01 mol/L溴化十六烷基吡啶溶液的用量均为1.0 mL时,可实现Zn2 与Cd2 、Mn2 、Al3 、Ni2 、Co2 、Fe2 等离子的定量分离,据此建立了浮选分离和测定锌的方法。该法对合成水样及加碘锌强化营养盐中微量锌进行分离测定,结果与原子吸收法相符,样品加标回收率为95.7%~105.3%,RSD为0.68%。     

不同材料表面纳米复合化学镀层镍-磷-硅酸锌的XPS和AES分析

对Q235碳钢片和D310硅钢片表面表面镍－磷－硅酸锌纳米复合化学镀层，用SEM观察外貌，称重法测定厚度；10％NaCl、1％H2S加速腐蚀试验，10％CuSO4溶液点滴试验循环伏安（CV）、抗粘性及抗高温氧化试验等测定其性能。用X－射线电子谱（XPS）及俄歇电子能谱（AES）测定其价态及组成。结果表明其性能优镍－磷镀层和其它微米复合化学镀层，表面的镀层Q235碳钢片优于D310硅钢片表面的镀层，镀层的原子百分组成为：D235碳钢片：Ni79.00,P10.06,Zn2.01,Si1.88,O5.87,C1.18;D310硅钢片：Ni80.50,P10.67,Zn1.70,Si1.52,O4.83,C0.78.     

电感耦合等离子体-原子发射光谱法同时测定不同种类蜂蜜中的20种微量元素

建立了电感耦合等离子体-原子发射光谱法(ICP-AES)同时测定蜂蜜中Na、K、Mg、Ca、Sr、Ba、Mn、Fe、Cu、Zn、Al、Se、Ni、Li、V、Cr、Co、Cd、As和Bi 20种微量元素的分析方法.样品无需消化,直接用硝酸溶解,配成稀酸溶液,上机测定.20种元素的加标回收率为75.2％～110％,相对标准...     

微波消解和直接溶解进样法测定板蓝根颗粒剂中六种金属元素的比较研究

目的使用微波消解和热酸溶液直接溶解板蓝根颗粒,运用火焰原子吸收光谱法测定这两种溶液中Fe、Zn、Cu、Mg、Ca和Mn 6种金属元素的含量。方法分别采用浓HNO3湿法微波消解和直接溶解板蓝根颗粒样品,用原子吸收分光光度计测定上述样品中6种金属元素含量。结果所测定的板蓝根颗粒中含有丰富的金属元素,两种前处理方法测定的结果相差很小。采用此法回收率在92.0%~110.0%之间,样品相对偏差小于3%。结论板蓝根颗粒中金属元素可作为人体元素的重要补充。     

火焰原子吸收法测定锌精矿中微量氧化钙

氧化钙的含量是衡量锌精矿品级的一项重要指标 ,因而对它的准确、快速测定有着重要的意义。锌精矿中氧化钙的含量通常采用火焰原子吸收光谱法进行测定。但由于在矿样中 ,一般硫的含量较高 ,试样经三酸溶解后 ,硫便以ＳＯ2 -4的形式存在于溶液中[1] ,导致氧化钙的测定结果严重偏低。本文从溶矿方法着手 ,通过溶样的途径来改变硫的存在形式 ,从而达到彻底消除干扰的目的 ,成功地测定了锌精矿中微量氧化钙的含量。1　试验部分1 .1　仪器与工作条件ＰＥ 3 0 3 0型原子吸收分光光度计钙空心阴极灯测定波长 42 2 .7ｎｍ ,光谱通带宽度 0 .7ｎｍ ,…     

电感耦合等离子体原子发射光谱(ICP-AES)法测定锌锭中的微量元素

建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定锌锭中的Pb、Cd、Fe、Cu、Sn 5种杂质元素的方法。样品用硝酸(1+1)溶解后,在稀硝酸介质中利用电感耦合等离子体原子发射光谱仪测定其中Pb、Cd、Fe、Cu、Sn的含量,测定的相对标准偏差(RSD,n=3)小于1.7%,对锌光谱标样BYG0505的测定结果与标准值基本一致。实现了对锌锭中多种杂质元素的简便、快速、准确的同时测定。     

Organogermyl,Organostannyl, and Organoplumbyl Phosphines,Arsines, Stibines,and Bismuthines

The preparation, properties, and reactions of the compounds named in the title are described, with particular reference to the possible participation of (p→d)_π components in the bonding between the group IVB and the group VB elements.     

Pyrenes,Peropyrenes, and Teropyrenes: Synthesis,Structures, and Photophysical Properties

The design of a relatively simple and efficient method to extend the π‐conjugation of readily available aromatics in one‐dimension is of significant value. In this paper, pyrenes, peropyrenes, and teropyrenes were synthesized through a double or quadruple benzannulation reaction of alkynes promoted by Brønsted acid. This novel method does not involve cyclodehydrogenation (oxidative aryl–aryl coupling) to arrive at the newly incorporated large arene moieties. All of the target compounds were synthesized in moderate to good yields and were fully characterized with the structures unambiguously confirmed by X‐ray crystallography. As expected, photophysical characterization clearly shows increasing red‐shifts as a function of extended conjugation within the fused ring systems.     

Structural, magnetic, and spectroscopic studies of YAgSn, TmAgSn, and LuAgSn

The rare earth-silver-stannides YAgSn, TmAgSn, and LuAgSn were synthesized from the elements by arc-melting and subsequent annealing. The three stannides were investigated by X-ray powder and single-crystal diffraction: NdPtSb type, P6₃mc, Z=2, a=468.3(1), pm, wR₂=0.0343, 353 F² values, 12 variables for YAgSn, and ZrNiAl type, P6¯2 m, a=726.4(2), , wR₂=0.0399, 659 F² values, 15 variables for TmAgSn, and a=723.8(2), , wR₂=0.0674, 364 F² values, 15 variables for LuAgSn. Besides conventional laboratory X-ray data with monochromatized Mo radiation, the structures were also refined on the basis of synchrotron data with , in order to clarify the silver-tin ordering more precisely. YAgSn has puckered, two-dimensional [AgSn] networks with Ag-Sn distances of 278 pm, while the [AgSn] networks of TmAgSn and LuAgSn are three-dimensional with Ag-Sn distances of 279 and 284 pm for LuAgSn. Susceptibility measurements indicate Pauli paramagnetism for YAgSn and LuAgSn. TmAgSn is a Curie-Weiss paramagnet with an experimental magnetic moment of 7.2 μ_B/Tm. No magnetic ordering is evident down to 2 K. The local environments of the tin sites in these compounds were characterized by ¹¹⁹Sn Mössbauer spectroscopy and solid-state NMR (in YAgSn and LuAgSn), confirming the tin site multiplicities proposed from the structure solutions and the absence of Sn/Ag site disordering. Mössbauer quadrupolar splittings were found in good agreement with calculated electric field gradients predicted quantum chemically by the WIEN2k code. Furthermore, an excellent correlation was found between experimental ¹¹⁹Sn nuclear magnetic shielding anisotropies (determined via MAS-NMR) and calculated electric field gradients. Electronic structure calculations predict metallic properties with strong Ag-Sn bonds and also significant Ag-Ag bonding in LuAgSn.     

Borinium, borenium, and boronium ions: synthesis, reactivity, and applications

Boron cations are elusive and highly electrophilic species that play a key role in the chemistry of boron. Despite early interest in the chemistry of boron cations, until recently they have largely remained chemical curiosities. However, hints at harnessing their potential as potent electrophiles have begun to appear and developments in weakly coordinating anion technology suggest that this is an area of research that is ripe for exploration. It has been nearly 20 years since the last major review on boron cations; herein we summarize the progress in the area since that time.     

Pi bonding and negative hyperconjugation in mono-, di-, and triaminoborane, -alane, -gallane, and -indane

A systematic quantum chemical investigation of mono-, di-, and triaminoborane, -alane, -gallane, and -indane is carried out to determine quantitatively the effects of pi bonding and negative hyperconjugation on structures, energetics, and rotational barriers in these systems. Pi bonding plays a significant role in the aminoborane compounds, but becomes rapidly less significant in the aminoalanes, -gallanes, and -indanes. For each main-group metal X investigated, X-N rotational barriers are found to be essentially equal depending only on the number of remaining in-plane amino groups. The contribution of negative hyperconjugation to reducing rotational barriers, as assessed from natural bond orbital (NBO) delocalization energies, is independent of the pyramidalization of the out-of-plane amino group, and is also dependent only on the number of rotated groups. Optimized tris[bis(trimethylsilyl)amino]-substituted structures of boron, aluminum, gallium, and indium are found to compare quite well with available experimental structural data, and exhibit X-N torsion angles that are independent of the central metal atom.     

Pyrenes,Peropyrenes, and Teropyrenes: Synthesis,Structures, and Photophysical Properties

The design of a relatively simple and efficient method to extend the π‐conjugation of readily available aromatics in one‐dimension is of significant value. In this paper, pyrenes, peropyrenes, and teropyrenes were synthesized through a double or quadruple benzannulation reaction of alkynes promoted by Brønsted acid. This novel method does not involve cyclodehydrogenation (oxidative aryl–aryl coupling) to arrive at the newly incorporated large arene moieties. All of the target compounds were synthesized in moderate to good yields and were fully characterized with the structures unambiguously confirmed by X‐ray crystallography. As expected, photophysical characterization clearly shows increasing red‐shifts as a function of extended conjugation within the fused ring systems.     

铬,硒,镉,锰与心脑血管疾病

通过对５０例心脑血管疾病病人及５０例健康对照组血中微量元素铬、硒、镉、锰的检测分析证实，心脑血管疾病病人血清Ｃｒ、Ｓｅ含量下降，Ｃｄ含量未见明显升高，并进一步探讨了这些微量元素与心脑血管疾病的发生发展的关系及其临床意义。     

Rare-Earth-compound nanowires, nanotubes, and fullerene-like nanoparticles: synthesis, characterization, and properties

Various low-dimensional nanostructures, such as nanowires, nanotubes, nanosheets, and fullerene-like nanoparticles have been selectively synthesized from rare-earth compounds (hydroxides, fluorides) based on a facile hydrothermal method. The subsequent dehydration, sulfidation, and fluoridation processes lead to the formation of rare-earth oxide, oxysulfide, and oxyhalide nanostructures, which can be functionalized further by doping with other rare-earth ions or by coating with metal nanoparticles. Owing to the interesting combination of novel nanostructures and functional compounds, these nanostructures can be expected to bring new opportunities in the vast research areas of and application in biology, catalysts, and optoelectronic devices.     

Transition-metal-free O-, S-, and N-arylation of alcohols, thiols, amides, amines, and related heterocycles

A new protocol for the Ullmann-type arylation process of different aromatic heterocycles without any transition-metal catalyst, implying the use of a combination of an excess of potassium hydroxide and dimethyl sulfoxide, is described. The reaction can be performed between a broad range of starting nucleophiles including phenol, alcohols, amines, nitrogen-containing five-membered systems such as pyrazoles, imidazoles, and indoles, and amides with haloarenes, iodide and bromide derivatives giving the best results, the possible pathway involving the in situ generation of the corresponding benzyne intermediate. When the reaction was performed with 2-iodoaniline and either carboxamides or isothiocyanato derivatives, the corresponding benzoazole derivatives were obtained.