离子色谱法测定饮用水中无机消毒副产物

采用直接进样离子色谱法,对饮用水中无机消毒副产物(DBP):ClOˉ2、BrO、ClOˉ3和Brˉ进行分离检测;研究了分离柱的选择、淋洗液的浓度和流速对分离的影响;在优化的条件下,4种离子的工作曲线范围为1．0～50μg／L;检出限为ClOˉ2 0.3μg／L、BrOˉ3 0.6μg／L、ClOˉ3 0.9μg／L和Brˉ0.6μg／L;4种离子的RSD(n=8)分别为3．8％、3．6％、4．0％和5．0％;本法操作简单、运行费用低、灵敏度高,应用于饮用水的分析。结果令人满意。     

高效毛细管电泳电导法快速检测复方维生素B片中的VBl、VBl2、VB6和VC

采用高效毛细管电泳电导法同时分离、测定了复方维生素B片中的主要成分VB1，VB12，VB6和VC的含量。研究了运行缓冲溶液的酸度和浓度、电泳电压、进样时间等因素对电泳的影响。在优化的实验条件下：40mmol/L Tris-4mmol/L H3BO3(pH8．0)的缓冲溶液中加入0．30mmol/L CTAB(溴化十六烷基三甲基铵)，分离电压为15kV，上述4组分在5min内得到良好的分离。维生素B1，B12，B6和VC的线性范围分别为5．5～1．0mg/mL；15～1．5mg／mL;1．0～0．40mg／mL和6．6～0．80mg／mL；检测限分别为0．80μg/mL，4．0μg/mL，0．50μg/mL，2．9μg/mL；5次测定峰高的相对标准偏差分别为2．2％，1．6％，3．9％，2．8％。5次测定的平均回收率分别为99％，94％，l00％，97％。     

高效毛细管电泳-电导检测对四环素衍生物分离测定的研究

运用毛细管电泳-电导检测方法对4种四环素衍生物——土霉素(OTC)、金霉素(CTC)、强力霉素(DOC)和四环素(TC)的分离进行了研究。在3．5mmol/L三羟基氨基甲烷(Tris)-7．5mmol/L柠檬酸(Cit)pH4．0的运行缓冲液中，4种四环素衍生物在15min内获得完全分离。四环素衍生物的线性范围分别为5．0-500μg/mL OTC，3．6-420μg/mL CTC，4.5-470μg/mL DOC和2.5-400μg/mL TC。检测限(S／N＝3)分别为OTC2．0μg/mL，CTC 1．8μg／mL，DOC2．5μg/mL和TC1．0μg/mL。采用本法对实际样品强力霉素片中强力霉素和土霉素片中土霉素进行测定，回收率分别为97．2％和96.4％。     

反胶束萃取-高效液相色谱法测定磺酸型偶氮染料

建立了水中磺酸偶氮染料甲基橙（MO）、刚果红（CR）和酸性铬兰K（ACBK）的反胶束萃取-离子对高效液相色谱定量检测的方法。采用Hypersil C18柱（250×4．6mm,5μm）,流动相为V（甲醇）／V（水）=63：37（含10mmol／L的KH2PO4、4mmol／L的四丁基溴化铵,KOH调pH=7．0）,流速为0.8mL／min,MO、CR和ACBK检测波长分别为449nm、505nm和526nm。结果表明,染料的回收率为92．9％～102．1％,相对标准偏差为0．9％～2．3％,水中MO、CR和ACBK的检出限分别为0．6μg／L、1．2μg／L和1．3μg／L。     

高效液相色谱法测定葡萄酒中的白藜芦醇

采用μ－BondapakC18（3．9mm×00mm）色谱柱,体积分数为40％的乙腈为流动相,紫外306nm检测,t-白藜芦醇和c-白藜芦醇的保留时间分别为7．7min和8．9min,回收率90．0％～97．8％,最小检出限10μg／L。检测11种国产葡萄酒,白藜芦醇的质量浓度从10．0到920．0μg／L不等。     

反相高效液相色谱法测定人血浆中利培酮及其代谢物的质量浓度

建立了测定人血浆中利培酮及其活性代谢物9-羟利培酮质量浓度的反相高效液相色谱方法。用Zor－baxODSC18色谱柱,以V（甲醇）：V（水）：V（1mol／L醋酸铵）：V（3mol／L氨水）＝300：50：3：1为流动相,检测波长为280nm,流速为0．8mL／min。利培酮的线性范围为2～600μg／L（r＝0．996）,回收率为（98．2±3．5）％,日内与日间的标准偏差分别为4．12％和4．83％;9-羟利培酮的线性范围为2～800μg／L（r＝0．998）,回收率为（97．8±3．8）％,日内与日间的标准偏差分别为4．28％和4．81％。     

毛细管电泳高频电导法测定虫草中的有效成份

建立了毛细管电泳高频电导法同时测定腺苷和虫草素的方法。实验对电泳介质的种类、浓度以及操作电压和进样时间等因素进行了优化,在4mmol／L乳酸＋10％异丙醇＋80μg／mL羟甲基纤维素钠（pH=4．0）,分离电压20．OkV的条下测定了天然虫草和人工虫草菌丝制品中的腺苷和虫草素的含量,线性范围分别为2．0μg／mL～120μg／mL和3．0μg／mL～110μg／mL,检出限分别为0．5μg／mL和1．0μg／mL。     

火焰原子吸收光谱法测定芦荟中微量铁、锌含量

用火焰原子吸收光谱法测定了芦荟中铁、锌两种微量元素含量。结果表明,芦荟中铁和锌千含量分别为638、244μg/g。火焰原子吸收光谱法测定样品中铁含量和锌含量的相对标准偏差分别为7．06％,3．63％,加标回收率在95％～102．5％范围内,检测限分别为0．011μg,／mL和0．002μg／mL。     

毛细管电泳高频电导法测定尿中MDMA及其代谢物

建立了尿样中MDMA及其代谢物MDA的毛细管电泳高频电导法检测分析方法。对电泳分离缓冲介质的种类、浓度、pH值以及分离操作电压和进样时间等实验条件进行了优化。缓冲液为2．5mmol／L NH4 Ac 0．5mmol／L HAc 2mmol／L SDS 10mmol／L β-CD,分离电压为15kV时,可实现较好的分离与检测。该法在2．5～80μg/mL范围内。MDMA和MDA线性相关系数r分别为0．998和0．999,检出限均为1．0μg/mL(S／N=3)。不同添加浓度水平尿样,日间和日内RSD均小于5％,回收率均在90％以上,适于法医毒物分析和临床药物监测的需要。     

固体吸附-毛细管气相色谱法测定环境空气中的偏二甲肼

采用固体吸附-毛细管气相色谱法测定环境空气中偏二甲肼的含量,色谱峰高与偏二甲肼浓度在0～13．8mg／L范围内线性关系良好,当采样体积为60L时,检出限和测定下限分别为0．37μg／m^3和1．2μg／m^3。低、中、高3种浓度的偏二甲肼标准溶液测定结果（n=6）的相对标准偏差分别为3．5％,2．6％,1．9％,样品加标回收率为84．5％～101．0％。     

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%.     

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.     

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.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.