宁波市饮用水中重金属污染物镉健康风险评价

对宁波市区内36个监测点的饮用水中Cd的质量浓度进行了调查研究,并应用目前美国环保局推荐的健康风险评价模型对各区饮用水中Cd所引起的健康风险度作了初步评价。结果表明,宁波市区镉的平均质量浓度范围为0～3.2μg/L;通过饮水途径所引起的致癌健康风险中Cd在邱隘的致癌风险最大(8.7×10-6.a-1),但低于国际辐射防护委员会(ICRP)推荐的通过饮水途径最大可接受风险水平(5×10-5.a-1)。由于邱隘地区饮用水中的镉风险度相对较高,因此应优先对其进行管理。总体来说,Cd的个人年风险在10-6水平,所以宁波市通过饮水所引起的慢性镉暴露不会对暴露人群引起健康危害。     

温州横阳支江地表水健康风险评价

对温州市横阳支江水的监测数据,利用风险评价模型进行了风险评价。结果表明,由非致癌物饮水途径健康危害的总风险值处在10^-8～10^-9水平,风险水平均远低于国际辐射防护委员会（ICRP）推荐的通过饮水途径最大可接受风险水平（5×10^-5a^-1）,因此通过饮水途径所引起的慢性非致癌物暴露不会对暴露人群引起健康危害。砷对暴露人群所导致的致癌风险在10^-5a^-1水平,风险水平均接近于国际辐射防护委员会（ICRP）推荐的通过饮水途径最大可接受风险水平,因此,应优先对砷进行管理。最后探讨了生态风险评价中存在的问题和尚需进一步研究的工作。     

火焰原子吸收光谱法测定红花中的Cu、Fe、Zn

采用火焰原子吸收光谱法和表面增敏的方法测定了红花中Cu、Fe、Zn的含量。实验表明,使用表面活性剂十二烷基硫酸钠(SDS),可使Zn的吸光度增感34.91%,使Cu增感37.39%,Fe增感232.10%。该法的检测限分别为Zn1.85×10-3μg/mL;Fe1.50×10-2μg/mL;Cu3.50×10-2μg/mL,加标回收率在99.37%~104.23%之间。该法灵敏度高,结果准确,可用于红花等中草药中Cu、Fe、Zn的同时测定。     

微波消解-端视ICP-AES测定茶叶中微量重金属元素

采用微波消解-端视等离子体原子发射光谱(ICP-AES)测定茶叶中微量重金属元素Pb、As、Cd、Cu、Fe,并对ICP-AES工作参数及条件进行了优化和选择。Pb、As、Cd、Cu、Fe的检出限分别为2.9×10-3μg/mL、5.2×10-3μg/mL、0.056×10-3μg/mL、0.55×10-3μg/mL、0.59×10-3μg/mL,线性范围为0~10000μg/L,相对标准偏差为1.7%~8.5%;回收率为90%~104%。该方法与国标法比较,结果无显著性差异。本法能用于茶叶测定。     

云南东川区域重金属环境暴露健康风险评价

以云南省昆明市东川主要河流及附近土壤、植物为研究对象,对其进行采样分析,并根据美国环境保护署(U.S.EPA)推荐健康风险评价方法对东川流域多种环境因素进行了重金属的健康风险评价。结果表明,水环境中致癌物质造成的风险最大,风险值在2.35×10^(-4)~8.27×10^(-4),达到U.S.EPA推荐的最大值10^(-4),植物根部的健康风险值为0.40×10^(-1)~7.00×10^(-1),茎叶部分的风险值为2.42×10^(-2)~15.24×10^(-2),根部存在的重金属对人体的健康风险约为茎叶部分的5倍;土壤中非致癌物质的健康风险影响较大,总健康风险值区间为0.64×10^(-1)~3.83×10^(-1)。评价结果可为该区域地表水、土壤和植物资源的污染治理、保护开发提供依据。     

黔产市售绿茶重金属的含量特征及健康风险评估

为研究黔产市售绿茶中重金属的含量分布特征及健康风险,以五个生产加工地的黔产市售绿茶为研究对象,分析其9种重金属(Pb、Cr、Cd、Hg、Cu、Zn、Mn、Ni和As)含量,利用美国环境保护署(USEPA)推荐的健康风险评价模型进行人体重金属的健康风险评价。结果表明,五种茶叶中Cr、Cd、Pb、Hg、Cu和As含量均低于国家限量标准。黔产市售绿茶的重金属浸出率大小次序为Zn>Mn>Hg>As>Cd>Pb>Cr>Cu>Ni。健康风险评价结果表明,五个产地的绿茶中重金属通过饮茶途径所产生的健康危害个人年风险大小次序为Cd>As>Mn>Ni>Cr>Hg>Pb>Zn>Cu,茶叶中重金属通过饮茶途径所产生的个人健康危害年风险总和为4.33×10-6~5.73×10-6 a-1,均低于USEPA和ICRP推荐的最大可接受风险水平,表明重金属引起的健康危害极小,其对暴露人群造成的健康危害可忽略不计,绿茶中重金属均处于安全范围内。     

锌-5-Br-PADAP-Zeph全差示分光光度法测定锌

本文研究了锌-5-Br-PADAP-Zeph三元络合体系的显色反应,其最佳显色酸度为pH6.5～7.5,最大吸收波长为560nm,表观摩尔吸光系数ε=1.25×10~5、组成比为Zn:5-Br-PADAP=1:4。锌量在0～20μg/25mL范围内符合比尔定律。络合物显色迅速并至少可稳定2小时。以下共存离子(以μg计)对10μg锌的测定无干扰:Mo,ca,Mg,Li(1000),W(500),Al,Cr,V,Mn,Fe,As,Ce(200),Pb(100),Bi(50),Zr(20),Cu(15),Ni(10),Sb(2.5),Ti(1.0);So_4~(2-),PO_4~(3-),F-无     

毛细管电泳分离检测中草药叶下珠中铜钴锌

以甲基百里酚蓝(MTB)为柱前配位剂,建立了毛细管电泳分离检测Cu、Co、Zn的方法。探讨检测波长、缓冲体系、缓冲液浓度、pH值及配位方式等对分离的影响。最佳实验条件为20 mmol/L Na2HPO4-NaOH 2.5×10-4mol/L MTB 60 mmol/L SDS(pH9.50)。线性范围为5.0×10-6mol/L~1.0×10-4mol/L,Cu、Co、Zn的检出限分别为2.0μmol/L、2.0μmol/L和1.0μmol/L。方法应用于经湿法消化处理的叶下珠样品中Cu、Co、Zn的测定,结果满意。     

ICP–AES法测定黄瓜中的8种元素

利用微波消解法消解样品,建立电感耦合等离子体原子发射光谱(ICP–AES)法,对大黄瓜和荷兰小黄瓜两种黄瓜样品中的K,Ca,Mg,Fe,Mn,Cu,Zn,Se 8种元素进行含量测定。K+线性范围为0~100μg/m L,Ca2+,Mg2+线性范围为0~20μg/m L,其余离子线性范围为0~2.0μg/m L,相关系数在0.999 6~1.000 0之间,样品加标回收测定结果的相对标准偏差均小于5%(n=6),加标回收率为93.4%~103.2%。结果表明人体所必须的常量元素K,Ca,Mg在两种黄瓜样品中均大量存在,荷兰小黄瓜中K,Ca,Cu,Mn的含量高于大黄瓜,而Fe,Mg,Se的含量低于大黄瓜,Zn在两种黄瓜样品中含量相当。该法可用于测定黄瓜样品中的K,Ca,Mg,Fe,Mn,Cu,Zn,Se元素含量。     

2—羟基—5—（1—甲庚基）苯甲醛肟萃取铜的性能

Comparative studies on the extraction of Cu(Ⅱ) have been performed by 2-hydroxy-5-(1-methylheptyl) benzaldoxime (N-590) without or with n-dodecanol as modifier, 2-hydroxy-5- (1-metylheptyl) benzophenone oxime (N-510), and 2-hydroxy-4-(1-methylheptyloxy) ben-zophenone oxime (N-530). When the extraction is carried out in feed liquor containing Cu1.03 g/L and Fe 10.7 g/L by 0. 1 mol·dm~(-3) extractant in kerosene, the Cu percentage extrac- tion of 95.6, 89 and 63%, and Cu(Ⅱ)-Fe(Ⅲ) separation factor of 1.46×10~3, 4.76×10~2and 1.26×10~2 are obtained with N-590, N-530 and N-510, respectively; moreover the Cuextraction and stripping speed with N-590 is greatly higher than that with N-530 and N-510. Addition of 2% n-dodecanol into 0.1 mol·dm~(-3) N-590 in kerosene improved the strip-ping behaviour.     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

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.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.