胶束电动毛细管色谱法同时测定复方化学消毒剂及日化产品中邻苯二甲醛、对氯间二甲基苯酚及三氯生

建立了邻苯二甲醛(OPA)、对氯间二甲基苯酚(PCMX)和三氯生3种杀菌剂同时分离测定的胶束电动毛细管色谱(MEKC)新方法。详细研究了影响上述3种杀菌剂同时分离与准确定量的因素: 如分离缓冲溶液的浓度及pH,十二烷基硫酸钠(SDS)浓度、样品缓冲溶液等。以40.2 cm (有效长度: 30 cm)×50 μm未涂层熔融石英毛细管为分离柱,20 mmol/L硼砂-80 mmol/L SDS(无需调pH)为分离缓冲溶液,2 mmol/L硼砂-8 mmol/L SDS (含体积分数为10%甲醇)为样品缓冲溶液,检测波长为214 nm。3种杀菌剂的校正峰面积的相对标准偏差(RSD)在1.1%～ 3.8%范围内,迁移时间的RSD均小于0.9%, OPA、PCMX和三氯生的检出限(LOD,信噪比为3)分别为4.0、0.4、0.4 mg/L,定量限(LOQ,信噪比为10)分别为12、1.2、1.2 mg/L,校正峰面积与相应的质量浓度分别在12～2 000 mg/L、1.2～200 mg/L和1.2～200 mg/L范围内具有良好的线性关系,相关系数分别为0.9994、0.9993和0.9995。该法前处理简单,可快速、准确地同时测定3种组分,非常适合常规实验室分析。     

高效毛细管电泳测定鸡蛋中三聚氰胺

建立了高效毛细管电泳-二极管阵列检测器检测鸡蛋中三聚氰胺的方法.样品用三氯乙酸提取,固相萃取小柱净化处理后进行检测,以50 mmol/L甲酸-50 mmol/L甲酸铵(pH 2.5)为缓冲溶液,在总长度为58.5 cm,内径为75 μm的毛细管中,分离时间约6 min,测得的定量限为0.25 mg/kg.三聚氰胺浓度在0.25～5.0 mg/kg范围内进行添加回收实验,平均回收率为80.2%～90.7%,相对标准偏差(RSD)为1.7%～3.4%.本方法简单易行、高效快速、经济环保,可以满足检测需要.     

毛细管电泳/非接触式电导法分离检测手性药物氨氯地平对映体

采用毛细管电泳/电容耦合非接触式电导( CE/C4 D),以18 mmol/L柠檬酸+6 mmol/L氨水+12 mg/L羟丙基甲基纤维素(HPMC)+ 35 mmol/L羟丙基-β-环糊精(HP-β-CD)为电泳运行液,熔融石英毛细管(50μm i.d.×45 cm,leff=40 cm),正高压(+15 kV)分离...     

毛细管电泳/非接触式电导法分离检测氧氟沙星对映体

采用毛细管电泳-电容耦合非接触式电导(CE-C4D),以20 mmol/L HAc + 6 mmol/L NaAc+12 mg/L羟丙基甲基纤维素(HPMC)+35 mmol/L羟丙基-β-环糊精(HP-β-CD)为电泳运行液,在熔融石英毛细管柱(45 cm×50 μm i.d.,有效长度 40 cm)中,正高压分离,手性药物氧氟沙星对映体获得良好的基线分离,线性检测范围为0.8～40 mg/L,检出限为0.3 mg/L.考察了电泳运行液组成、二元手性选择剂(HP-β-CD和HPMC)的浓度、进样方式和样品基质等对灵敏度和分离度的影响.本方法应用于市售外消旋和左旋氧氟沙星片剂中对映体的分离测定.     

高效毛细管电泳法测定牛奶和奶粉中残留的三聚氰胺

建立了牛奶和奶粉中三聚氰胺的高效毛细管电泳-二极管阵列检测器(HPCE-DAD)检测方法。使用长度58.5 cm、内径75 μm的毛细管柱,分离电压25 kV,进样量3.5 kPa (35 mbar)×8 s,分离温度25 ℃,缓冲溶液20 mmol/L 柠檬酸-40 mmol/L 磷酸氢二钠(pH 2.6),检测波长232 nm。分析物在1~100 mg/L 范围内线性良好,r2>0.997;牛奶和奶粉的定量限分别为0.5 mg/kg和1.0 mg/kg。在添加水平为定量限浓度至50 mg/kg时的回收率为72.2%~97.3%,相对标准偏差为2.1%~3.9%。     

双胶束电动毛细管色谱测定复方化学消毒剂中聚六亚甲基单胍、聚六亚甲基双胍、醋酸洗必泰和苄索氯铵

建立了双胶束电动毛细管色谱(MEKC)分离测定复方化学消毒剂中有效成分聚六亚甲基单胍(PHMG)、聚六亚甲基双胍(PHMB)、醋酸洗必泰(CHA)及苄索氯铵(BTC)的新方法。以50.2 cm(有效长度:40 cm)×50 μm i.d.未涂层熔融石英毛细管为分离柱,20 mmol/L硼砂+30 mmol/L十二烷基硫酸钠(SDS)+5 mmol/L脱氧胆酸钠(SD)+0.8 g/L聚乙二醇 20000为分离缓冲溶液。详细研究了分离缓冲溶液中各组分浓度、样品提取液对分离的影响。4种物质的检出限和定量限均分别为1 mg/L和3 mg/L。4种物质的校正峰面积与相应质量浓度在3~140 mg/L范围内,均具有良好的线性关系,相关系数均大于0.999。回收率在84.1%~109.6%间,相对标准偏差(RSD)均低于6%。用该法测定了11件复方化学消毒剂样品中PHMG、PHMB、CHA和BTC,与产品标识值基本吻合。该法可成功区分单胍与双胍,且操作简单,适用于消毒产品的质量监督。     

毛细管电泳-电化学发光法测定小鼠血浆中粉防己碱含量

血浆样品用氯仿萃取,所得萃取液在60℃水浴上用吹氮蒸干,用500μL甲醇溶解残渣,所得溶液用电驱动方法进样引入毛细管中进行毛细管电泳(CE)分离。采用的进样电压为12 kV,进样时间为7 s。电泳缓冲溶液为pH 7.5的20 mmol.L-1磷酸盐缓冲溶液,分离电压为15 kV。电化学发光法(ECL)与CE相联用作为检则方法。ECL反应系在400μL反应池中进行,反应池中盛有5 mmol.L-1Ru(bpy)32+溶液和pH 8.0的50 mmol.L-1磷酸盐缓冲溶液。采用的检测电位为1.15 V(vs.Ag/AgCl),所测得的ECL强度值与粉防己碱的质量浓度在0.05~80.0 mg.L-1范围内呈线性关系,其检出限(3S/N)为0.02 mg.L-1。在小鼠血浆样品的基础上加入粉防己碱标准溶液进行回收试验,测得其回收率在93.3%~95.0%之间。     

生物组织中丝氨酸对映体的毛细管电泳-非接触式电导分离检测

采用高效毛细管电泳-非接触电导检测法, 使用未涂层石英毛细管(50 μm i.d.×45 cm, L_eff=40 cm), 以3.2 mmol/L氢氧化钠+0.4 mmol/L柠檬酸+2.5 mmol/L乙酸铜+5.0 mmol/L L-精氨酸+15.0 mg/L 羟丙基甲基纤维素为电泳运行液, 实现了未衍生化的D,L-丝氨酸对映体的基线分离和检测. 其线性范围为0.35~30 mg/L, 检出限(S/N=3)为0.10 mg/L. 对影响分离度的因素如手性选择剂、 电泳运行液的组成和浓度、 分离电压和进样方式等进行了探讨. 结果表明, 该方法无需衍生化预处理, 高效低耗, 可实现常见氨基酸共存组分的不干扰测定, 能有效测定小鼠脑组织样品中的D-丝氨酸含量.     

毛细管电泳中移动反应界面法富集和检测尿样中的氧化苦参碱

采用建立在移动反应界面理论上的体系进行尿样中氧化苦参碱的富集与定量检测。与传统的毛细管电泳相比,体系中引入了富集缓冲溶液(富集相)和分离缓冲溶液(分离相)。优化的条件如下:样品缓冲溶液为20 mmol/L 甲酸钠(用氨水调节pH至10.70),富集缓冲溶液为40 mmol/L 甲酸-甲酸钠(pH 2.60),分离缓冲溶液为100 mmol/L 甲酸-甲酸钠(pH 4.80);样品相压力进样1.4 kPa×3 min,富集相压力进样1.4 kPa×7 min,紫外检测波长210 nm,电压21 kV。氧化苦参碱在2.2~65 mg/L的质量浓度范围内呈良好的线性关系(r=0.9991),检出限为0.74 mg/L,灵敏度比常规毛细管电泳方法提高约70倍,重现性良好。该方法已经成功地应用于尿样中氧化苦参碱的检测。     

毛细管电泳-方波安培法分离检测滴鼻液中的麻黄碱

在熔融石英毛细管 (75mm× 5 0cm )中 ,以 5mmol/LTris(三羟甲基氨基甲烷 ) +5mmol/LH3 BO3(pH =6 .5 )为电泳介质 ,采用毛细管电泳 方波安培检测法 ,实现了滴鼻液中盐酸麻黄碱的分离检测。探讨了缓冲溶液的种类、浓度、pH值、检测电位等因素对分离检测效果的影响。线性范围为 0 .8～ 2 0 2mg/L ,检出限为 0 .3mg/L ,回收率为 92 %～ 10 4 %。     

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.