气相色谱-串联质谱法测定乌龙茶中5种氨基甲酸酯类农药

建立了乌龙茶中5种氨基甲酸酯农药(速灭威、异丙威、仲丁威、残杀威和抗蚜威)同时测定的气相色谱-串联质谱(GC-MS/MS)分析方法。样品经正己烷-乙酸乙酯(1∶1)混合溶液提取后,通过400 mg PSA/400 mg C18/1 200 mg Mg SO4的Qu ECh ERS试剂盒进行净化,Rxi-5 Sil MS毛细管柱(30 m,0.25 mm×0.25μm)进行分离,串联质谱进行定性定量分析。5种农药在各自的线性范围(速灭威和残杀威为5~500μg/kg,异丙威、仲丁威和抗蚜威为1~500μg/kg)内具有良好的线性关系,相关系数(r2)均大于0.99;在5,20,100μg/kg 3个加标水平下,速灭威和残杀威的平均回收率为77.5%~95.4%,相对标准偏差(RSD,n=6)为2.1%~6.1%,检出限和定量下限分别为1μg/kg和5μg/kg;在1,20,100μg/kg 3个加标水平下,异丙威、仲丁威和抗蚜威的平均回收率为79.5%~102.5%,RSD为2.0%~8.2%,检出限和定量下限分别为0.2μg/kg和1μg/kg。该方法操作简单、灵敏度高、重现性好,可满足乌龙茶样品中5种氨基甲酸酯类农药残留的分析要求。     

偏最小二乘-分光光度法同时测定福美锌和代森锰农药残留量

利用紫外可见分光光度法研究了农药福美锌和代森锰与苯基荧光酮的相互作用,发现反应后的产物分别在波长为551和554 nm处最大有吸收,但光谱严重重叠.实验采集了450～700 nm波长范围吸光度数据,并对该数据进行一阶求导后用偏最小二乘法处理,据此建立了偏最小二乘-分光光度法同时测定福美锌和代森锰两种农药的新方法.福美锌和代森锰的线性范围分别为0.3～6.0和0.2～3.5 μg/mL;检出限分别为0.22和0.13 μg/mL.混合样品分析无需分离,方法简单、快速.用于水果、大米和自来水等实际样品测定.     

偏最小二乘-同步荧光光谱法同时测定两种蒽环类抗生素

将偏最小二乘法(PLS)用于同步荧光光谱严重重叠的多柔比星(doxorubicin, DOX)和柔红霉素(daunorubicin, DNR)两组分混合体系进行波谱解析, 建立了该混合体系含量同时测定的新方法. 在pH 3.45 B-R缓冲溶液中, 波长差Δλ=55 nm时, 用测得的25个混合标样的同步荧光原始光谱、一阶导数光谱值建立模型. DOX和DNR在质量浓度为0.05～3.0 μg/mL范围内呈现良好的线性关系, 所建立的测定二者模型的相关系数分别为0.9897和0.9909; 平均回收率分别为101.0%和101.4%; 预测均方根误差(RMSEP)分别为0.1400和0.1395; 预测相对标准误差(SEP)分别为0.1541和0.1525. 该方法可应用于尿液样品的分析测定.     

固相萃取-高效液相色谱法测定茶叶中有机氮农药残留量

提出了茶叶中5种有机氮农药(速灭威、残杀威、呋喃丹、甲萘威、抗蚜威)残留的高效液相色谱法.样品用丙酮-正己烷(1 2)混合溶剂提取,经石墨碳固相小柱净化,以VP-ODS C18柱分析,乙腈-60 mmol·L-1磷酸(40 60)溶液为流动相,流速为1.0 mL·min-1,检测波长210 nm,外标法定量.在0.10～2.0 mg·kg-1之间的添加水平,5种有机氮农药的平均回收率在80.1%～94.8%之间,相对标准偏差在2.21%～7.13%之问,检出限在0.0125～0.05 mg·kg-1之间.     

化学计量学-荧光分析法同时测定萘、1-萘酚和2-萘酚

根据正交信号校正(OSC)、小波包变换(WPT)及偏最小二乘法(PLS)的算法原理,编制了名为POSC-WPTPLS的程序,结合荧光分析法快速、灵敏、选择性较好的优点,将该程序用于同时测定荧光光谱严重重叠的萘、1-萘酚和2-萘酚多组分体系,并将3种化学计量学方法(OSC-WPT-PLS、WPT-PLS和PLS)进行比较...     

化学计量学-分光光度法同时测定饲料中的诺氟沙星、氧氟沙星和洛美沙星

在pH1.81的Britton-Robinson(B-R)缓冲溶液中对诺氟沙星、氧氟沙星和洛美沙星三组分混合溶液进行光度测定,所得的重叠光谱数据用经典最小二乘(CLS),主成分回归(PCR),偏最小二乘(PLS)和径向基人工神经网络(RBF-ANN)方法处理和分析,结果表明RBF-ANN对合成样中三种药物浓度的预报结果...     

月桂酸胶束电动毛细管色谱快速测定氨基甲酸脂类农药的研究

以月桂酸表面活性剂和氨水组成缓冲溶液,建立了毛细管胶束电动色谱快速测定七种氨基甲酸脂类农药的方法。对电泳介质的种类及浓度、pH值、操作电压和进样时间等影响因素进行了优化,以45 mmol/L月桂酸(乙醇溶)和120 mmol/L氨水(用0.1 mol/L NaOH调至pH=9.5)为电泳介质,在4.5 min内实现对速灭威、残杀威、克百威、抗蚜威、异丙威、硫双威、双氧威的分离检测。结合固相萃取(SPE)对农田水样进行测定,各农药检出限为2.0～15μg/L,回收率为85%～107%,相对标准偏差为4.3%～8.3%。     

荧光素染料与富马酸酮替芬的光谱研究及应用

在弱酸性缓冲介质中,富马酸酮替芬和某些卤代荧光素类染料(曙红Y、荧光桃红和曙红B)借助静电引力和疏水作用力形成离子缔合物,引起共振光散射光谱、吸收光谱及荧光光谱的变化。实验表明,曙红Y体系灵敏度最高。对曙红Y、荧光桃红和曙红B体系,线性范围分别为0.12~8.4μg/mL、0.24~8.4μg/mL和0.18~6.0μg/mL,检测限分别为12.72 ng/mL、12.52μg/mL和18.21μg/mL。方法已用于分析富马酸酮替芬片剂、血清及尿样。     

氨基甲酸酯类杀虫剂速灭威酶联免疫吸附分析方法研究

利用间-甲酚和β-丙氨酸合成了速灭威半抗原β-(间-甲基苯氧基羰基)氨基丙酸(HOM)。通过活泼酯法将HOM交联于牛血清白蛋白(BSA)和卵清蛋白(OVA)上;HOM-BSA为免疫原制备了速灭威的兔抗血清,ELISA法测得其效价高达1.28×106,交叉反应测定表明抗体方法特异性识别速灭威。对离子强度等影响因素进行了研究,确定了速灭威酶联免疫吸附分析方法(ELISA)的最佳工作条件,建立了定量测定速灭威的间接竞争ELISA方法,结果表明,该方法检测线性范围为1~10000μg/L;IC50为40.74μg/L;检出限为0.08~0.10μg/L;批内相对标准偏差为2.9%;批间相对标准偏差4.6%。土壤、稻谷和水中的平均添加回收率分别为80%、93.4%和107%。本研究建立了一种快速检测环境和农产品中速灭威残留的有效方法。     

荧光光谱法测定残杀威的研究

残杀威是一种新型的有机合成杀虫剂,在λex=277 nm,λem=336 nm处发射荧光,经β-环糊精增敏后,荧光强度大为增强.据此建立了测定残杀威的新方法.在0.80～8.0 ng/mL浓度范围内,残杀威荧光强度与浓度呈良好的线性关系,相关系数r为0.9994;检出限为0.17 ng/mL; 相对标准偏差为1.1%.该体系的抗干扰能力及稳定性好.本法已成功用于蔬菜中残杀威残留的测定.     

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%.     

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.     

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.     

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.     

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.     

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.     

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.