微柱分离-ICP-MS测定高纯氧化钆中14种稀土杂质

研究了采用自制微柱分离装置分离Gd2O3基体的条件。99．9％以上基体被分离，分离周期为36min。建立了高纯Gd2O3中分离Gd后测定Yb、Lu以及内标补偿法直接测定其它12种稀土杂质的ICP—MS分析方法.定量下限为0．08～0．80μg／g，加标回收率为85％～115％，相对标准偏差为1．1％～8．5％、方法可满足快速测定99．999％ Gd2O3中14种稀土杂质的要求。     

高效液相色谱法测定动物组织样品中黄曲霉毒素的残留量

采用免疫亲合技术,对动物肝脏和肌肉中黄曲霉毒素残留进行了提取和纯化处理,建立了一种快速、灵敏、简便的测定动物组织中黄曲霉毒素B1、B2、G1、G2的高效液相色谱方法。用反相HPLC分离,柱后光化学衍生,荧光检测器测定黄曲霉毒素含量,保留时间定性,峰面积定量,测定了样品和标准样。结果表明,4种毒素可在10min内完成分离;线性范围为15～1500pg;线性回归系数大于0．9998。用本方法对动物肝脏和肌肉样品进行了加标回收实验,4种黄曲霉毒素的平均回收率为68．71％～83．42％;相对标准偏差为3．51％～7．40％;检出限均达到2．65pg。     

离子色谱法测定乙二胺水溶液中的SO32-、SO42-

用离子色谱法测定5％乙二胺水溶液中的SO3^2-、SO4^2-。选用IonPac柱，以3mmol/L AS11分离碳酸钠－10％甲醇水溶液作为淋洗液，20min内便可完成测定。SO3^2-和SO4^2-的回收率分别为97.6%-101.6%和99.2%-101.0%，相对标准偏差分别为1．31％和1．42％。     

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％。     

抑制型离子色谱法测定白酒中的F-、Cl-、NO2-、H2 PO4-、NO3-

用抑制型离子色谱法测定白酒中的F^-、Cl^-、NO2^-、H2PO4^-、NO3^-。流动相为4mmol／LNa2CO3—3 mmol／LNaHCO3混合溶液，流速为1．5mL／min，进样量为0、5mL，在最佳色谱条件下，5种无机阴离子10min内实现基线分离。F^-、Cl^-、NO2^-、H2PO4^_、NO3^-的检出限分别为0、008、0．012、0、030、0．068、0．077mg／L。测定结果的相对标准偏差分别为1．86％、1．30％、2．06％、1．82％、1．50％，回收率分别为108．0％、94．0％、101．0％、98．7％、94．4％。     

复方维生素B片中主要成分的高效毛细管电泳电化学法检测

采用高效毛细管电泳－电化学检测法同时测定复方维生素B片中的主要成分维生素B1，B12，B6和C的含量；研究了电极电位，运行缓冲溶液的浓度和酸度，电泳电压和进样时间等对电泳的影响，以微铂电极为工作电极，检测电位＋0．5V（vs SCE)，在pH9.0的15mmol/L Tris-1mmol/L H3BO3缓冲溶液中，上述4组分在5min内获得基线分离；维生素B1，B12，B6和C的线性范围分别为2．1mg/L-1.0g/L,6.0mg/L-0.80g/L,1.4mg/L-0.72g/L和0．97mg/L-0.44g/L检出限分别为0．50mg/L,1.0mg/L,,0.65mg/L和0．40mg/L；5次测定峰高的相对标准偏差分别为2．4％，3．0％，3．1％，和2．5％，5次测定的平均回收率分别为99％，102％，98％和100％。     

高效液相色谱法测定山生柳中酚苷类成分的含量

用高效液相色谱法测定山生柳中水杨苷、水杨酰水杨苷和木犀草素07－O－葡萄糖苷的含量，流动相为1．5％醋酸溶液－甲醇，Symmetry C18柱，柱温30℃，流速1．1mL/min，检测波长270nm，线性浓度范围分别为527．0－105．4um/mL,140-28.0ug/mL,81.0-16.2ug/mL，平均回收率是104．9％和103．6％，RSD分别为2．0％，0．3％和0．3％。     

固相萃取-高效液相色谱法测定水中酚类物质

研究了高效液相色谱法测定水产中的酚类物质，水样中的酚用Waters Porapak^* Sep-Park固相萃取小柱预分离和富集，以C18为固定相，线性梯度洗脱为流动相，流速1.0mL/min，梯度条件为：A：1％的醋酸乙腈溶液、B：O.05mol/L磷酸二氢钾缓冲溶液，按开始（20％A＋80％B），20min(80%A 20%B)线性变化，各组分均在其最大吸收波长下检测，14种酚回收率在92．8％－108％之间，RSD在1．9％－3．7％之间 ，最低检测浓度达μg/L级，方法用于环境水样中痕量酚的测定，结果令人满意。     

液相色谱/质谱法分离鉴定碘化酪蛋白水解产物中的碘化氨基酸

用Waters Symmetrys Shield^TM RP18柱，乙腈(B，含0．1％甲酸)和水(A，含0．1％甲酸)为流动相，0．8mL／min，线性洗脱(B从10％到50％)40min，液质联用(LC／MS)，电喷雾电离源(ESI^ ，SIR方式)，对碘化酪蛋白水解物中的一碘酪氨酸(MTT)、二碘酪氨酸(DIT)、二碘甲腺原氨酸(T2)、三碘甲腺原氨酸(L3,rT3)和四碘甲腺原氨酸(T4)进行了分离确证。同时测定了T3、rT3和T4的含量。     

整体柱离子对色谱对铬(Ⅵ)的快速测定

研究了基于硅胶整体柱的离子对色谱快速测定Cr（Ⅵ）的方法,讨论了淋洗液浓度、乙腈浓度、流速、温度和pH等因素对分离的影响。用1．0mmol／L四丁基氢氧化铵-0．8mmol／L邻苯二甲酸（pH6．0）作为淋洗液,流速6．0mL/min,可以在1min内快速分离测定Cl^-、NO3^-、Cr（Ⅵ）、SO4^2-离子。Cr（Ⅵ）的检出限为1．02mg／L,保留时间和峰面积的相对标准偏差（RSD）（n=5）分别为0．2％和0．3％。将方法应用于测定地下水中的Cr（Ⅵ）,回收率为104％。     

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.     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.