固相微萃取-气相色谱-质谱联用分析环境水样中痕量有机磷农药

研究了固相微萃取(SPME) 气相色谱 质谱联用(GC MS)同时测定环境水样中二嗪农、甲基对硫磷、对硫磷和水胺硫磷4种有机磷农药(OPPs)的分析方法。选择聚丙烯酸酯(PA)萃取纤维,对SPME的条件如萃取时间、萃取溶液的pH值和离子强度、解吸温度、解吸时间和GC MS的条件进行了优化。对二嗪农和水胺硫磷方法线性范围为0.001～10μg L,对甲基对硫磷和对硫磷方法线性范围为0.001～100μg L。二嗪农、甲基对硫磷、对硫磷、水胺硫磷的检出限分别为0.015,0.020,0.013和0.039μg L。分析加标自来水、矿泉水和湖水样品,回收率在89.0%～102%之间,RSD在2.1%～14.1%之间。适合于环境水样中痕量OPPs的快速分析。     

固相微萃取-高效液相色谱-荧光检测法测定番茄中的多菌灵和噻菌灵

建立了应用固相微萃取(SPME)-高效液相色谱(HPLC)-荧光检测法测定番茄中多菌灵(MBC)和噻菌灵(TBZ)的分析方法。考察了萃取纤维、萃取时间、萃取温度、解吸时间、解吸液组成、解吸模式、pH值、有机溶剂和离子强度对MBC和TBZ萃取效率的影响,对SPME条件和色谱条件进行了优化。SPME在室温下进行,采用65 μm聚二甲基硅氧烷/二乙烯苯（PDMS/DVB）萃取纤维,萃取溶液中加入100 g/L NaCl,搅拌速度为1100 r/min,萃取时间为50 min。将该法用于番茄中MBC和TBZ的测定,MBC和TBZ的定量线性范围均为0.01~1.0 mg/kg;线性相关系数分别为0.9958和0.9967;检出限分别为0.003和0.001 mg/kg;回收率分别为83.5%和85.6%(n=5),相对标准偏差(RSDs)分别为6.5%和3.8%。该方法操作简单,无需使用有机溶剂,适于分析番茄样品中的MBC和TBZ。     

自制离子液体固相微萃取涂层分析人体尿液中的五氯酚

建立了顶空固相微萃取与气相色谱法（HS-SPME-GC）测定人体尿液中五氯酚（PCP）的新方法。 采用溶胶-凝胶法,加入自制的离子液体键合固相微萃取涂层,优化了萃取温度、萃取时间、pH值、离子强度及解吸时间。 结果表明,样品中加入3 g NaCl,溶液的pH值为2,并以一定速度搅拌的条件下,在80 ℃顶空萃取50 min,300 ℃下解吸5 min,方法的检测限为5.0 ng/L,线性范围为0.05～100 μg/L,相对标准偏差(RSD)为5.9%,加标回收率为106.6%。     

固相微萃取-高效液相联用分析环境水样中的痕量■

 应用固相微萃取与高效液相联用技术 (SPME HPLC)分析了环境水样中的痕量 艹屈 。对SPME的条件如萃取时间、萃取温度、离子强度、解吸方式、解吸溶剂、解吸时间和HPLC条件进行了优化 ,建立了SPME HPLC分析环境水样中痕量 艹屈 的方法 ,并将其用于分析自来水、雨水、矿泉水和江水等实际水样。方法的线性范围为 0 0 13μg/L～ 3 0 μg/L ,检出限为 2 7ng/L ,相对标准偏差 (RSD ,n =6 )为 5 6 % ,回收率为 10 3 2 %～ 119 3%。该方法适合于环境水样中痕量 艹屈 的分析 ,体现了SPME在样品前处理中快速、灵敏、简单、无溶剂的特点。     

固相微萃取气相色谱法测定水产品中五氯苯酚及其钠盐残留量

采用自动固相微萃取(Automated SPME)超声波辅助萃取技术(UE)与气相色谱联用测定水产品中五氯苯酚及其钠盐残留量.实验优化了SPME直接萃取技术,样品调pH 2,超声波40℃萃取30 min后,用85μm聚丙烯酸酯(PA)萃取头90℃自动搅拌萃取30 min,270℃解吸5 min.最低检出量为0.01μg/kg;五氯苯酚线性范围0.001～10 μg/L,r=0.9999;对鳕鱼加标五氯苯酚1.0、5.0μg/kg回收率分别为71.0%～80.0%、77.2%～91.4%,相对标准偏差(RSD)为6.3%和8.6%(n=3).该方法简便、灵敏、稳定,无溶剂污染,是测定水产品中五氯苯酚及其钠盐残留量的理想方法.     

土壤中痕量水胺硫磷的微波辅助萃取-固相微萃取-GC-MS法测定

研究了微波辅助萃取(MAE)-固相微萃取(SPME)联合萃取、气相色谱-质谱法(GC-MS)测定土壤中水胺硫磷的分析方法；采用正交设计试验优化了微波升温程序、萃取温度、萃取时间、萃取溶剂体积等MAE条件；研究了SPME萃取涂层、萃取时间、解吸温度等对萃取效率的影响；方法的线性范围在1．O～20μg/L之间，检出限为O．49ng/g；测定25、100ng/g加标土壤样品，回收率分别为79％和107％。RSD分别为2．6％和6．5％；方法综合了MAE快速高效和SPME富集浓缩的优点，以水为萃取溶剂，特别适合于固体样品中痕量有机物的分析。     

顶空固相微萃取/气相色谱法快速测定水中氯代苯胺类残留

建立了固相微萃取/气相色谱法(SPME/GC)同时测定水中13种氯代苯胺的方法。优化了GC测定条件,研究了纤维头类型、萃取温度、萃取时间、萃取pH值、离子强度和解吸时间对萃取效果的影响。在优化条件下,各目标组分在一定浓度范围内线性关系良好,检出限为0.05~0.34μg/L。用于实际水样分析,加标回收率为76.0%~121%,相对标准偏差为0.3%~17.2%。方法可用于水体中13种氯代苯胺的快速痕量分析。     

固相微萃取-高效液相色谱联用测定水样中的痕量苯并(k)荧蒽

研究了固相微萃取(SPME)-高效液相色谱(HPLC)联用测定水样中痕量苯并(k)荧蒽的的分析方法。对SPME的条件如萃取时间、萃取温度、离子强度、解吸方式、解吸溶剂、解吸时间和HPLC条件进行了优化，建立了SPME-HPLC联用分析水样中痕量苯并(k)荧蒽的方法，并用于自来水、雨水和纯净水等实际水样的分析。SPME优化的条件为室温、搅拌速度1100r／min、萃取时间30min、甲醇解吸溶剂、解吸时间2min。HPLC的条件为C18反相色谱柱、甲醇流动相、流速1mL/min、紫外检测器、波长244nm，以峰高为测量信号。方法的线性范围为0～8．00μg／L，检出限为0．014μg／L，相对标准偏差(n=6)为6．7％，回收率为82．0％～104．2％。该方法适合于水样中痕量苯并(k)荧蒽的分析。     

一次性固相微萃取-高效液相色谱法测定环境水样中的3种多环芳烃

以涂有聚二甲基硅氧烷(PDMS)的石英光导纤维作为固相微萃取纤维,建立了一次性固相微萃取与高效液相色谱联用测定环境水样中的菲、荧蒽和屈3种多环芳烃(PAHs)的方法。实验考察了解吸时间、萃取时间、搅拌速度、盐效应以及样品溶液pH值对萃取效率的影响,优化得到的萃取和解吸条件为: 于60 mL样品溶液中放入两段萃取纤维(1.5 cm)和1.2 g氯化钠,在1200 r/min搅拌速度下萃取60 min,取出萃取纤维并转入120 μL甲醇中密封静置解吸24 h后,取20 μL解吸液进行液相色谱测定。该方法对于菲、荧蒽和屈的检出限分别为0.17、0.17和0.08 μg/L;精密度(以测定0.5 μg/L PAHs标准溶液6次的相对标准偏差计)小于8%;实际样品中3种PAHs的加标回收率为80.0%～107%。该方法快速简便,纤维一次性使用,克服了污染物在纤维上残留的问题。     

超声辅助离子液体分散液相微萃取-高效液相色谱法测定废水中雌激素的研究

将离子液体、分散液相微萃取与超声萃取技术结合,采用疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐([C4 MIM][PF6])为萃取剂,建立了超声辅助离子液体分散液相微萃取-高效液相色谱法分析废水中3种雌激素物质(己烯雌酚、双烯雌酚、己烷雌酚)方法.试验采用50μL的离子液体,考察了溶液体积、溶液pH值、超声时间、静置时间、离心时间等因素对富集效果的影响.最佳的萃取条件为:溶液体积为6 mL,甲醇体积0.3 mL,溶液pH值为2.0,超声时间6min,静置时间30min,离心时间10 min.在优化的萃取条件下,3种雌激素的富集倍数可达到96.8～112.4倍;方法的线性范围为0.5-100.0μg/L;检出限为0.25～0.50μ/L.对浓度为5.0μg/L的3种物质测定6次的相对标准偏差为9.2%～10.8%.     

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.     

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.     

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.     

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.