固相萃取-气相色谱法测定动物组织中盐酸克伦特罗残留量

建立了固相萃取-气相色谱分析动物组织中盐酸克伦特罗残留量的方法．采用固相萃取,分离富集动物组织中的盐酸克伦特罗．肉样的加标回收率在70％～80％;最低检出限为1μg／kg．盐酸克伦特罗的硅烷化衍生产物,采用气相色谱(ECD检测器)检测,其衍生物的峰面积与样品浓度在0．005～1．0μg／mL范围内呈良好的线性关系,线性回归系数大于0．999．     

气相色谱-质谱法测定肝脏组织中盐酸克伦特罗和盐酸菜克多巴胺

建立了同时测定动物肝组织中盐酸克伦特罗和盐酸莱克多巴胺残留量的固相萃取-气相色谱-质谱分析方法。动物肝组织样品在碱化的条件下用乙酸乙酯和异丙醇混合溶剂提取，提取液浓缩后用乙酸乙酯溶解，然后再用稀盐酸反萃取去除脂肪，调pH值后经SCX固相萃取（SPE）柱净化，洗脱液经氮气吹干后经双三甲基硅基三氟乙酰氨（BSTFA）衍生，采用选择离子模式（盐酸克伦特罗：86、212、262、277，盐酸莱克多巴胺：163、192、234、250）进行测定，外标法定量。盐酸克伦特罗和盐酸莱克多巴胺的检出限分别为0．30和1．00μg／kg。盐酸克伦特罗添加浓度在1．0～5．0μg／kg范围内，添加回收率为77．4％～88．3％；相对标准偏差（RSD）为3．1％～5．1％；盐酸莱克多巴胺添加浓度在4．0～20．0μg／kg，添加回收率为69．8％～82．1％；相对标准偏差（RSD）为3．5％～4．9％；衍生物的峰面积与被测物浓度分别在0．003～1．00mg／L和0．012～4．00mg／L范围内呈良好的线性关系，线性回归系数均大于0．999。     

固相萃取-高效液相色谱法同时测定克伦特罗和沙丁胺醇

提出用固相萃取 -高效液相色谱法同时测定饲料中微量克伦特罗和沙丁胺醇的新方法。选用 Dikma Diamonsil C18-ODS分析柱 (2 0 0× 4.6mm,5μm) ,乙腈 -0 .0 1mol/ L KH2 PO4 (p H 3 .0 )作流动相 ,应用波长编程进行检测。克伦特罗和沙丁胺醇的线性范围为 0 .1～ 1 0 0μg/ m L,相关系数分别为 0 .99999和 0 .99977,检出限分别为0 .3 1 ng/ m L和 0 .2 4ng/ m L ,回收率分别为 91 .2 %～ 92 .0 %和 91 .9%～ 93 .0 % ,相对标准偏差分别是 1 .2 0 %～ 2 .0 5%和 1 .2 9%～ 2 .51 %。     

气相色谱-质谱法测定肝脏组织中盐酸克伦特罗和盐酸莱克多巴胺

建立了同时测定动物肝组织中盐酸克伦特罗和盐酸莱克多巴胺残留量的固相萃取-气相色谱-质谱分析方法。动物肝组织样品在碱化的条件下用乙酸乙酯和异丙醇混合溶剂提取,提取液浓缩后用乙酸乙酯溶解,然后再用稀盐酸反萃取去除脂肪,调pH值后经SCX固相萃取(SPE)柱净化,洗脱液经氮气吹干后经双三甲基硅基三氟乙酰氨(BSTFA)衍生,采用选择离子模式(盐酸克伦特罗:86、212、262、277,盐酸莱克多巴胺:163、192、234、250)进行测定,外标法定量。盐酸克伦特罗和盐酸莱克多巴胺的检出限分别为0.30和1.00μg/kg。盐酸克伦特罗添加浓度在1.0~5.0μg/kg范围内,添加回收率为77.4%~88.3%;相对标准偏差(RSD)为3.1%~5.1%;盐酸莱克多巴胺添加浓度在4.0~20.0μg/kg,添加回收率为69.8%~82.1%;相对标准偏差(RSD)为3.5%~4.9%;衍生物的峰面积与被测物浓度分别在0.003~1.00 mg/L和0.012~4.00 mg/L范围内呈良好的线性关系,线性回归系数均大于0.999。     

顶空固相微萃取-气相法测定酒中的甲醇和杂醇油

 采用环氧树脂作为固相涂层制作固相微萃取 (SPME)装置 ,建立了顶空固相微萃取 气相法 (HS SPME GC)测定酒精饮料中甲醇和杂醇油的方法 ,并对萃取条件和条件进行了优化。方法的检出限为 0 0 2mg/L～0 0 4mg/L ,相对标准偏差为 1 4 %～ 4 1% ;与顶空气相法相比 ,灵敏度可提高 2 0倍～ 30 0倍。将该法用于啤酒、葡萄酒和保健酒中的甲醇和杂醇油的测定 ,加标回收率为 80 8%～ 110 3% ;与顶空气相法 (国家标准方法 )进行了比较 ,相对误差不大于 7 3%。该法简便、快速、灵敏、精密度好 ,拓宽了SPME的应用范围。     

气相-质谱法测定粮谷中恶草酮的残留量

 应用微量化学法和固相萃取技术 ,建立了粮谷中恶草酮残留量的气相 质谱 (GC MS)测定方法。用苯 正己烷 (体积比为 1∶1)萃取 ,中性氧化铝小柱净化。净化液用GC MS测定 ,采用外标法定量。恶草酮在大米中的回收率为 90 4%～ 115 .7% ,RSD为 2 %～ 6 % ,在玉米中的回收率为 81 3%～ 10 9 7% ,RSD为 4%～ 9% ,最低定量检出限为 0 0 0 5mg/kg。该法快速、灵敏、准确 ,各项技术指标均满足农药残留检测的要求。     

动物尿液中盐酸克伦特罗的分子印迹固相萃取-气相色谱-质谱法研究

采用分子印迹聚合物(MIP)固相萃取小柱提取、净化并富集猪尿液中的盐酸克伦特罗分子,用N,O-双三甲基硅基三氟乙酰胺(BSTFA)衍生化,毛细管气相色谱-质谱联用(选择离子模式,选择离子为277、262、243和86)对衍生物分析。优化了MIP固相萃取柱的淋洗条件,考察了MIP固相萃取柱的净化效果和消除基体干扰能力,建立了对动物尿液中盐酸克伦特罗的定性、定量分析的方法。在优化条件下,本法检出限(LOD)为0.51μg/L,定量限(LOQ)为1.00μg/L;不同盐酸克伦特罗加入量的回收率为71.0%~89.3%;相对标准偏差为3.2%~9.7%。将该方法与农业行业标准方法比较,结果吻合较好。但该方法灵敏度和精密度高,操作更为简单、快捷。     

饲料中盐酸克伦特罗、沙丁胺醇高效液相色谱测定

建立了用液相色谱法同时测定饲料中违禁药物盐酸克伦特罗、沙丁胺醇含量的方法 ;样品经甲醇 -盐酸溶液提取后 ,经液 -液萃取、固相萃取小柱净化 ,用ZorbaxCN柱分离 ,二极管阵列检测器检测、外标法定量 ;盐酸克伦特罗、沙丁胺醇的定量下限(w)分别为0.10×10-6 、0.36×10-6,回收率分别大于88 %和74 % ,RSD(n=5)分别小于6.4 %和3.0%。     

固相萃取-气相色谱／质谱同时测定卷烟滤嘴中的四种芳香胺

采用固相萃取-气相色谱/质谱(SPE-GC/MS)法同时测定了卷烟抽吸后滤嘴中截留的1-氨基萘、2-氨基萘、3-氨基联苯和4-氨基联苯四种芳香胺.该法采用5%的盐酸超声振荡提取滤嘴中的芳香胺,提取液经液液萃取后进行衍生化和固相萃取,浓缩后进行GC/MS分析.1-氨基萘、2-氨基萘、3-氨基联苯和4-氨基联苯的检出限分别为0.51、0.42、0.18、0.18 ng/mL,相对标准偏差在0.94%～3.02%之间,回收率在92.67%～97.20%之间.该方法用于卷烟滤嘴中四种芳香胺的测定,结果发现不同材料的滤嘴对四种芳香胺有不同的截留作用.     

固相萃取-反相高效液相色谱法测定水中的邻苯二甲酸酯

建立了固相萃取-反相高效液相色谱法检测水中3种邻苯二甲酸酯类物质邻苯二甲酸二甲酯、邻苯二甲酸二(2-乙基己基)酯、邻苯二甲酸二正辛酯的方法. 考察了固相萃取柱、洗脱溶剂、洗脱体积、上样速度以及洗脱速度对萃取效率的影响. 通过综合分析, 选定SupelcleanLC-18 SPE Tube固相萃取柱, 甲醇为洗脱剂, 洗脱体积2 mL, 上样速度为4 mL/min, 洗脱速度为1 mL/min. 在此萃取条件下, 萃取回收率在83.4%～121.2%之间. 邻苯二甲酸二甲酯、邻苯二甲酸二(2-乙基己基)酯、邻苯二甲酸二正辛酯质量浓度在2～100 mg/L之间均为线性. 经萃取后, 方法的最低检出限分别为邻苯二甲酸二甲酯0.06 μg/L, 邻苯二甲酸二(2-乙基己基)酯0.16 μg/L, 邻苯二甲酸二正辛酯0.08 μg/L. 方法的精密度在10%～15%之间. 应用该方法测定自来水中酞酸酯类化合物的含量, 加标回收率为83.6%～110.2%.     

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.