高效液相色谱-串联质谱法测定烟草中有机磷农药的残留量

建立了一种基于液相色谱-串联质谱法(LC-MS/MS)定量分析微量有机磷农药残留的方法,并应用于烟草中农药残留物的定量检测。采用乙腈超声提取烟草中的有机磷农药残留,以甲醇-水（含0.1%乙酸铵）(体积比为95∶5)为流动相,经高效液相色谱分离,以串联质谱在多反应监测(MRM)模式下测定,在2.5 min内完成了甲胺磷、乙酰甲胺磷、乐果、敌百虫、毒死蜱5种常用有机磷农药的定量分析。5种农药在1~200 μg/L内的线性关系良好(r>0.998),平均回收率为77%~104%,检出限为1.0~5.0 μg/kg。     

超声辅助固相萃取/离子阱气相色谱-质谱联用测定蔬菜中有机磷农药残留

通过超声辅助固相萃取提取并富集蔬菜中残留的乐果和氧化乐果等9种有机磷农药,采用离子阱二级质谱定性并定量检测其含量,建立了气相色谱-质谱联用测定蔬菜中有机磷农药残留的分析方法.结果表明,所建立的方法简单,快速,灵敏度高.9种有机磷农药的检出限为0.02～0.04 μg/mL,添加回收率为75.07％～99.47％.     

基于SnO2气体传感器农药残留的动态检测及定性定量分析

研究了一种快速检测和识别农药敌百虫、乙酰甲胺磷气体新方法,即动态俭测方法：这种方法利用单个SnO2气体传感器而非阵列在方波温度调制的状态下可实现两种农药气体的定性分析,实验结果表明、在0．02Hz的调制频率、250～300℃的温度调制范围,传感器对单一组分的农药残留表现出高的选择性和稳定性;利用FFT频谱和极坐标构建完成对敌百虫和乙酰甲胺磷的定性和定量分析。     

固相微萃取-气相色谱法测定红葡萄酒中残留的有机磷农药

采用溶胶-凝胶包埋技术制备了耐高温固相微萃取头(SPME),用该萃取头与气相色谱-热离子化检测器联用对红葡萄酒中的12种有机磷农药残留进行了测定。实验中对搅拌速度、萃取时间、盐浓度等条件进行了优化。结果表明,在样品用量25 mL,搅拌速度1250 r/min,盐浓度 150 g/L,萃取时间30 min的条件下,绝大多数组分峰面积的相对标准偏差（RSD）在5%以下,各种有机磷农药的检测限为5 ng/L到0.38 μg/L。     

毛细管气相色谱法测定韭菜中13种有机磷农药残留的研究

建立了毛细管气相色谱法测定韭菜中敌敌畏、甲胺磷、乙酰甲胺磷、甲拌磷、氧化乐果、久效磷、乐果、毒死蜱、甲基对硫磷、马拉硫磷、杀螟硫磷、对硫磷和喹硫磷等13种有机磷农药残留的新方法.考察了进样口压力和程序升温速率对色谱分离的影响.试样用乙腈提取,经毛细管气相色谱柱DB-1701(30 m×0.32 mm×0.25 μm)分离,FPD检测器测定.当进样口压力为68.9 kPa,程序升温速率为5 ℃/min时,13种有机磷农药与韭菜基质在30 min内获得有效分离.添标水平为0.05、0.2 mg/kg时的平均回收率为78% ～115%,相对标准偏差为2.6% ～10.7%,方法检出限(S/N=3)为0.01 ～0.03 mg/kg,符合农药多残留定性、定量分析技术的要求.     

固相微萃取(SPME)/GC/MS测定灌溉水中的残留甲胺磷

农药残留是当前农产品出口及内销中的最大卫生质量问题，由水携带是农药残留的来源之一。本文利用SPME／GC／MS技术对灌溉用水农药残留进行了分析研究，对固相微萃取条件进行了选择，并作了加入回收实验，测定了水中的甲胺磷含量。     

二氧化锡气体传感器对有机磷农药残留的动态检测

研究了一种快速检测和识别农药敌百虫、乙酰甲胺磷和乐果气体的新方法,即动态检测方法。这种方法利用单个SnO2气体传感器而非阵列在方波温度调制的状态下可实现3种农药气体的快速检测。实验结果表明：在0．02Hz的调制频率和250—300℃的温度调制范围,传感器表现出高的选择性和稳定性;利用FFT频谱和极坐标构建完成对敌百虫、乙酰甲胺磷和乐果的定性和定量检测。     

微型固相萃取柱结合胃袋式大体积进样-气相色谱-质谱法同时快速测定菠菜中的13种有机磷农药残留

利用微型固相萃取柱对样品进行前处理,采用胃袋式大体积进样技术结合气相色谱-质谱(GC-MS),建立了菠菜中13种有机磷农药残留的同时快速分析方法。以保留时间和特征离子丰度比定性,以峰面积外标法定量,以3倍信噪比实验值确定方法的检出限(LODs),以10倍信噪比实验值确定方法的定量限(LOQs)。结果表明,除乐果外,其余12种有机磷农药的添加回收率为76.8%～114.0%,相对标准偏差为1.5%～17.6%,LODs为0.5～25 μg/kg。该方法前处理简单快速,分析成本低,分析时间短,灵敏度、准确度和精密度均符合农药多残留检测技术的要求,适用于食品中多种有机磷农药残留的快速灵敏检测。     

有机磷农药残留掌上检测仪的设计

设计了一种能够实现现场检测的有机磷农药残留掌上检测仪,其能够快速筛查有机磷农药污染的蔬菜,保障果蔬类农产品市场安全.基于酶抑制率法测量原理,以发光二极管(LED)为光源,设计双光电检测电路,由硅光电二极管进行信号采集,信号经单片机进行数据处理,实现了吸光度值和抑制率数字显示.与传统分光光度计相比,本实验设计的检测仪巧小轻便(127 mm×77 mm×35 mm)、方便携带,可实现现场零距离检测.实验表明,在乐果农药浓度为0.1~1.0?g/m L范围内,抑制率与乐果浓度呈良好线性,相关系数为0.9986,检出限为0.058?g/m L.将其应用于蔬菜中有机磷农药残留的测定,检测结果与国标方法有良好的相关性,能够对蔬菜中有机磷农药残留进行现场快速分析检测,具有实际的应用价值.     

蔬菜中甲胺磷等5种有机磷农药残留量的分散液-液微萃取/气质联用技术检测

建立了分散液-液微萃取/气相色谱质谱(DLLME/GC-MS)联用技术分析蔬菜样品中甲胺磷、甲拌磷、甲基对硫磷、毒死蜱和乐果5种有机磷农药残留的新方法。优化后的萃取条件:10μL氯苯为萃取剂,1.0 mL丙酮为分散剂,萃取时间为3 m in。5种有机磷农药均具有良好的线性关系,相关系数不低于0.995,加标回收率为60%~95%,相对标准偏差为2.8%~9.1%,检出限为0.001~0.140 mg/kg。应用于蔬菜中有机磷农药残留的检测,结果满意。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

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.     

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.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.