气相色谱-负化学源质谱联用法测定菊酯类农药

通过固相萃取-气相色谱-负化学离子源质谱技术建立了11种拟除虫菊酯类农药残留的检测方法,并应用于茶叶农残检测.样品经乙酸乙酯提取后,用串联的活性炭和中性氧化铝固相萃取柱选择性地富集茶叶中待测组分,再由气相色谱-负化学离子源质谱分时段选择离子监测技术进行测定.方法简单快速,一次进样就能得到11种菊酯残留结果;准确度和精密度高,在0.016 μg/kg、0.032 μg/kg和0.064 μg/kg 3个添加水平下的回收率在70%～110%之间,CV≤7.4%;选择性好,消除了色素和其它杂质干扰;灵敏度高,检出限低,除了氯菊酯为10 μg/kg外,其它菊酯检出限都在μg/kg级,七氟菊酯则达到了0.02 μg/kg.     

基质固相分散和GC-NCI-MS法分析果汁中拟除虫菊酯农药残留量

建立了基质固相分散法（MSPD）和气相色谱-负化学离子源-质谱法（GC—NCI—MS）应用于果汁中10种拟除虫菊酯农药残留量的快速分析方法，并对这些农药NCI—MS的阴离子结构与断裂机理进行初步探讨。采用以中性氧化铝为吸附刺、Florisil硅藻土为净化剂和乙酸乙酯为洗脱剂的MSPD样品前处理方法，以PCB103为内标物和GC—NCI—MS的选择离子监测方式（SIM）进行定性与定量分析。当样品的加标浓度水平为50、250μg／kg时，平均加标回收率为86．7％～114．8％，相对标准偏差为1.9％～14．1％；除氯菊酯农药的方法检出限（MDL）为14.7μg／kg外，其余农药的MDL大都小于1．0μg／kg；线性范围为10～500μg／kg，相关系数都大于0.997，在所分析的大部分果汁中至少分析出两种以上的拟除虫菊酯农药残留。     

利用固相萃取-气相色谱-负化学离子源质谱技术快速分析茶叶中3种杀螨剂和八氯二丙醚农药残留

建立了茶叶中3种杀螨剂及八氯二丙醚农药残留快速分析的固相萃取-气相色谱-负化学离子源质谱检测(GC-NCI-MSD)方法,并应用于出口欧盟茶叶中农残检测及基地监管.样品经正己烷-丙酮(1∶1,V∶V)提取后,用固相萃取柱(Agela)除去茶叶中干扰物质,以环氧七氯为内标物,经气相色谱-负化学离子源质谱分时段选择离子监测...     

气相色谱-负化学电离质谱测定蔬菜中啶虫丙醚的残留量

建立以固相萃取净化和气相色谱-负化学质谱(GC/NCI/MS)技术快速测定蔬菜中啶虫丙醚残留量的方法。经乙腈提取,共提物中的基体杂质经PSA/SAX固相萃取柱去除,用负化学源质谱检测,灵敏度选择性高于气相色谱-电子轰击源质谱。目标农药的平均回收率为87.0%～91.0%,平均相对标准偏差为6.45%～6.80%(n=7),方法的检出限为1μg/kg。     

气相色谱-质谱法同时测定番茄制品中拟除虫菊酯类农药残留

番茄制品经乙腈提取,盐析,氟罗里硅土固相萃取小柱净化,微池电子捕获检测器(μECD)负化学源质谱(NCI—MS)并联对净化液进行检测,一次进样可对番茄制品中的9种拟除虫菊酯类农药残留准确定量和确证。μECD回收率为87．6％～107．0％;相对标准偏差为5．5％～11．3％;检出限为0．0005～0．005mg／kg;负化学源选择离子(NCI-SIM)模式回收率为91．9％～109．7％;相对标准偏差为5．2％～12．7％;检出限为0．0005～0．005mg／kg(氯菊酯除外),两者之问没有显著的差别。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。     

中药材中5种拟除虫菊酯农药残留量的测定

研究中药材中5种拟除虫菊酯农药残留量的测定方法。用石油醚-丙酮混合溶剂超声提取，固相萃取法净化，用气相色谱-电子捕获检测器（ECD）测定。5种拟除虫菊酯农药在3种代表性中药材的加标回收率为72．6％-135．0％，相对标准偏差为3．6％。27％；方法的检出限为0．001—0．005μg／g。方法灵敏度高，选择性好，操作较为简便，适用于植物性（根、茎类）药材中5种拟除虫菊酯农药残留量的测定。     

气相色谱质谱联用法对农产品中8种种衣剂农药残留的同时测定

应用气相色谱-质谱联用仪（GC-MS）建立了水果、蔬菜、粮谷等农产品中8种种衣剂农药残留的分析测定方法。样品用乙腈提取,通过石墨化碳或C18固相萃取小柱净化,经DB-5ms气相色谱柱分离,电子轰击电离（EI）、选择离子监测模式（SIM）对定量离子和定性离子进行MS测定。标准工作曲线范围0．02-0．5mg／L。样品中添加水平为0．005、0．010和0．020mg／kg时,回收率为74％～110％;相对标准偏差小于15％。检出限（S／N=3）为0．09～0．77μg／kg。     

动物组织中己烯雌酚残留的基体固相扩散-气相色谱-质谱分析方法研究

采用基体固相扩散和固相萃取结合的方法提取并净化动物肝脏组织中残留的己烯雌酚，用N-甲基，N-三甲基硅烷三氟乙酰胺衍生化，毛细管气相色谱-质谱联用(选择离子模式，选择离子为：383、397、412、413)对衍生物检测分析，确立了对动物肝脏组织中己烯雌酚定性、定量分析的方法。该法检出限低于1μg/kg；不同DES加入量的回收率为81．6％-100．9％；相对标准偏差8．7％-13．2％。     

气相色谱-负化学离子源质谱联用法测定植物性产品中多组分农药残留量

通过气相色谱-负化学离子源质谱技术建立了同时检测18种农药残留的分析方法. 样品经正己烷和丙酮混合溶剂及正己烷提取后, 用活性炭-中性氧化铝混合小柱净化, 再由气相色谱-负化学离子源质谱分时段选择离子监测技术进行测定. 一次进样就能得到18种农药残留结果;各农药在0.005、 0.01和0.02 mg/kg 3个添加水平的平均回收率在70.2%～115.3%之间, RSD<12%, 检出限为0.01～6 μg/kg, 方法可应用于8种植物性产品中的农残检测.     

分散固相萃取气相色谱-负化学离子源质谱法测定大豆和玉米中20种农药的残留量

建立了一种大豆和玉米中20种农药残留量的分散固相萃取气相色谱-负化学离子源质谱分析方法。样品经乙腈提取并浓缩后加入N-丙基乙二胺（PSA）、石墨化碳黑和C18 3种填料进行分散固相萃取净化,气相色谱-负化学离子源质谱分时段选择离子监测技术测定与确证,外标法定量。所有农药在20～400 μg/L范围内线性均良好;方法的定量限(LOQ)均不高于2 μg/kg;在5,10和20 μg/kg 3个添加水平下所有农药的平均回收率均处于70%～130%之间,相对标准偏差(RSD)低于17%;运用该方法检测大豆和玉米样品时没有干扰现象。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.