密闭消解ICP-AES测定土壤及沉积物中主量和微量元素

利用高压密闭消化系统,采用王水-H2O2和HF-HNO3-H2O2两种消化液消化土壤标准物质GBW07403和GBW07404,用ICP-AES测定,研究土壤元素的测定方法。结果表明,土壤中的Al、As、Ca、Cr、Cd、Co、K、Cu、Fe、Mg、Mn、Na、Mo、Ni、P、Pb、Zn测定值与给定的标准值吻合,两种消化液测定值的相对标准偏差均小于2.6%。     

电感耦合等离子体质谱法(ICP-MS)同时测定正山小种红茶中18种微量元素

采用微波消解样品,应用电感耦合等离子体质谱法(ICP-MS)同时测定正山小种红茶中Na、Mg、K、Ca、Fe、Al、Zn、Mn、Cu、Ge、Cd、Cr、Ni、Se、Mo、Hg、As和Pb 18种元素。对于所测元素校准曲线的相关系数0.9990,回收率范围为90.1%～108.1%,相对标准偏差为1.54%～7.57%。正山小种红茶中Na、Mg、K、Ca、Fe、Al、Zn、Mn、Cu、Ge、Cd、Cr、Ni、Se、Mo、Hg、As和Pb 18种元素可用ICP-MS法同时测定,方法简便、快速、准确,灵敏度高。     

半密闭酸溶-电感耦合等离子体质谱（ICP-MS)）法测定化探样品中的铬镍铜锌镉铅6种重金属

采用半密闭酸溶消解法处理样品，选择离线校正的方式校正了Sn对Cd的同量异位素的干扰，增加积分时间和读数次数提高了Cd的准确度和精密度，建立了电感耦合等离子体质谱仪（ICP-MS）测定化探样品中Cr、Ni、Cu、Zn、Cd、Pb六种重金属元素的方法。对前处理方法和仪器的参数条件进行了优化，结果表明，半密闭体系可达到回流的目的，样品分解完全且无污染现象，在最优的实验条件下，标准曲线的相关系数均不小于0.9997，检出限为0.019~1.65 μg/g ，测定下限为0.057~4.95 μg/g 。按照实验方法对岩石、水系沉积物和土壤国家标准物质中Cr、Ni、Cu、Zn、Cd、Pb平行测定12次，各元素的测定结果与认定值基本一致，相对偏差均不大于3.55%，相对误差均不大于 10.34% 。采用实验方法对土壤样品进行分析，测定结果与四酸溶解-ICP-OES测定Cr、Ni、Cu、Zn、Pb，火焰-石墨炉原子吸收法测定Cd的结果基本吻合。     

新疆喀什市农田土壤重金属特征分析

目的对新疆喀什市农田土壤重金属特征进行分析,方法采用火焰原子分光光度计测定土壤中的重金属Cu、Zn、Pb、Cr、Cd、Ni。结果农田土壤在不同深度土层的重金属Cr、Cd、Cu、Ni、Pb、Zn含量分布规律均为0~20 cm土层20~40 cm土层40~60 cm土层,即在土壤表层聚集。结论棉田土壤的Cd、Cu、Ni、Pb、Zn的含量均高于小麦土壤,且Cd含量略高于土壤背景值。     

电感耦合等离子体质谱法(ICP-MS)测定土壤中的重金属元素

采用电感耦合等离子体质谱法(ICP-MS)测定了国家标准土壤样品中的部分重金属元素(Cd,Cu,Pb,Zn,Cr,Ni,Mo)的含量,其测定值与推荐值相符,准确度符合国家标准要求。各元素方法的检出限满足要求,相对标准偏差(RSD)介于0.91%~4.3%,加标回收率介于94%~106%。方法简便快速,结果准确,可以运用于大批量地质样品中的部分重金属元素含量的同时测定。     

丹-锡高速公路两侧土壤中重金属元素污染的测定与评价（英文）

论文对丹-锡高速公路两旁土壤中重金属Pb、Cd、Cr、Cu、Zn、Fe、Ni和Mn元素的含量进行了采样调查。分别用单项污染指数、内梅罗指数和地累积指数对土壤中重金属元素的污染状况进行了评价。结果表明:高速公路两旁栽种防护林对土壤重金属污染起到一定的防护作用。随着距路基中心距离的增加,土壤pH值变化范围不大,土壤略呈弱酸性,土壤中Pb、Zn、Mn、Cd和Cu的含量呈现下降的趋势,Fe、Cr、Ni的含量在距路基10~30m范围内略有增加。公路两侧土壤中Pb含量超过背景值,但没有引起污染,Zn、Cr和Cd含量处于轻度到中度污染。土壤中Pb、Cd、Zn、Fe和Cu来自于同一类污染源。     

ICP-MS测定土壤中的部分重金属元素*

本文采用ICP-MS法测定了土壤国家标准样品中的部分重金属元素(Cd、Cu、Pb、Zn、Cr、 Ni、Mo)的含量,其测定值与推荐值相符,准确度符合要求。各元素方法的检出限满足要求,精密度介于0.91％～4.34％,加标回收率介于94％～106％。该方法简便快速,结果准确,可以运用于大批量地质样品中的部分重金属元素含量的同时测定。     

高压微波消解-电感耦合等离子体质谱(ICP-MS)法测定小米样品中铜铅锌镉铬镍砷

准确测定小米中的重金属对控制和提高食品安全具有非常重要的意义。采用高压微波消解法以HF-H2O2体系处理样品,选择52Cr、60Ni、63Cu、66Zn、75As、111Cd、208Pb为测量同位素,采用He气模式的碰撞反应池技术测定Cr和As,采用仪器自带干扰校正公式对Cd的测定结果进行校正,建立了电感耦合等离子体质谱(ICP-MS)法测定小米样品中Cu、Pb、Zn、Cd、Cr、Ni、As的方法。重点对溶样条件进行了优化,结果表明在优化的实验条件下,校准曲线的相关系数均不小于0.999 7,检出限为0.0005~0.010 μg/g,测定下限为0.002~0.40 μg/g。按照实验方法对小米成分分析标准物质中Cu、Pb、Zn、Cd、Cr、Ni、As平行测定12次,各元素测定值与认定值基本一致,相对标准偏差（RSD）均在7.0%以内。采用实验方法对蔚县小米样品进行分析,结果表明本方法灵敏度高,重现性好,定量准确,可用于大批量小米样品的测定。     

预富集单波长激发能量色散X射线荧光光谱法现场测定地表水中10种重金属

为实现现场快速定量分析地表水中的多种重金属元素,建立了一种树脂预富集-单波长激发能量色散X射线荧光光谱法现场准确快速测定地表水中Cr(Ⅵ)、Mn、Fe、Co、Ni、Cu、Zn、As、Cd、Pb 10种元素的分析方法。对该方法其中的树脂预富集条件进行了优化,结果表明最佳预富集条件为：树脂粒度38μm-75μm;水样体积30mL;水样流速6mL/min;预富集完成后即刻测量;样品pH值为5。在方法学方面考察了该方法的检出限、精密度、正确度,其中Cr(Ⅵ)、Cu、Zn、As、Cd、Pb 元素的检出限低于地表水环境质量标准GB 3838-2002的限值要求;精密度中相对标准偏差范围为2.13%~10.4%;加标回收率为90.0%~114%之间。采用该方法测定实际地表水样品,并与ICP-MS法进行比对,其测定结果基本一致。研究表明该方法检出限可以满足地表水中Cr(Ⅵ)、Mn、Fe、Co、Ni、Cu、Zn、As、Cd、Pb 的检测要求,精密度和准确性较好。该研究对地表水中无机元素分析方法的拓展进行了有益尝试和积累,并为后续相关标准制订提供有益参考。     

基于全反射X射线荧光光谱测定污水痕量重金属元素

以Ga为内标,探究全反射X射线荧光光谱（TXRF）快速测定多质量梯度浓度多元素重金属溶液Mn、Fe、Co、Ni、Cu、Zn、As、Cd、Sn、Sb和Pb的可行性,并以实际生活污水为研究对象,比较分析了离心、过滤和消解3种预处理方式对测定污水中重金属元素的影响。实验结果表明,Mn、Fe、Co、Ni、Cu、Zn、As和Pb,较适宜用TXRF直接进行定量分析;Pb的Lα与As的Kα谱线重叠,致使As的回收率略高于其它元素;Cd、Sn和Sb元素,仅可用于趋势分析。当质量浓度为40和4 mg/L时,Mn、Fe、Co、Ni、Cu、Zn和Pb元素呈现出较高的准确度和精密度,回收率在99%～117%之间,相对标准偏差（RSD）处于1%～14%。随着质量浓度的逐渐降低,各元素的准确度和精密度表现出不同程度的下降,当质量浓度处于本次试验的最低水平4μg/L时,大部分元素的回收率与RSD已超出定量分析的要求。通过对生活污水的3种预处理方式进行比较,发现污水悬浮颗粒同样携带部分金属元素,经消解后,Mn、Fe、Co、Ni、Cu和Zn这6种元素的准确度和精密度最好,质量浓度范围在36～152μg/L之间,回收率均...     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.