亚临界水萃取及液相色谱-串联质谱法检测猪肉中β-受体激动剂与氯霉素残留

建立了亚临界水萃取及液相色谱-串联质谱法(LC-MS/MS)检测猪肉中β-受体激动剂和氯霉素的方法。样品酶解后,经亚临界水萃取,C18粉未净化,目标物经Agilent XDB-C18柱(4.6 mm×50 mm,1.8μm)分离,采用液相色谱-串联质谱法多反应监测(MRM)模式检测,基质匹配溶液内标法定量。优化条件下,沙丁胺醇和莱克多巴胺在1.0～32.0μg/L范围内线性关系良好,其定量下限(S/N>10)为0.5 ng/g,检出限(S/N>3)为0.25 ng/g;克伦特罗和氯霉素在0.2～6.4μg/L范围内线性关系良好,其定量下限(S/N>10)为0.1 ng/g,检出限(S/N>3)为0.05 ng/g,相关系数均大于0.99。猪肉基质在3个加标水平下,回收率为79.2%～113.6%,相对标准偏差(RSDs)为3.2%～12.0%。该方法的灵敏度、准确度和精密度均符合兽药残留测定的技术要求,适用于猪肉中β-受体激动剂和氯霉素残留的检测。     

气相色谱-串联质谱法同时测定染整助剂中乙二醇醚及其醋酸酯残留量

以乙酸乙酯为萃取溶剂对染整助剂中残留的乙二醇醚及其醋酸酯进行超声萃取后,经Waters Sep-Pak Vac Silica(1 g/6 mL)固相萃取柱净化,选用DB-Wax色谱柱(60 m×0.25 mm×0.25μm)分离,采用气相色谱-串联质谱(GC-MS/MS)方法进行多反应监测(MRM)分析,外标法定量,建立了同时测定染整助剂中15种乙二醇醚和4种乙二醇醚醋酸酯的分析方法。结果显示,19种待测物峰面积(A)与其质量浓度(ρ)在一定范围内呈线性相关,相关系数均不低于0.999 2。分别以3倍信噪比(S/N=3)和S/N=10计算方法检出限(LOD)和定量下限(LOQ),得MOPA和DEGME的LOD均为30μg/kg,DEGDEE的LOD为20μg/kg,EGEE和EGME的LOD均为10μg/kg,其余14种目标分析物的LOD为1～5μg/kg;MOPA和DEGME的LOQ均为100μg/kg,EGEE、EGME和DEGDEE的LOQ分别为20、30、50μg/kg,其余14种目标分析物的LOQ为1～15μg/kg。在低、中、高3个加标浓度水平下的平均加标回收率为82.4%～94.6%,相对标准偏差为2.7%～9.2%。该方法操作简单、灵敏度高、定量下限低,完全满足染整助剂中乙二醇醚及其醋酸酯残留量检测工作的需要。     

超声萃取/气相色谱-质谱联用法同时测定皮革及其制品中21种有害有机溶剂的残留量

建立了气相色谱-质谱/选择离子监测方法,对皮革及其制品中21种有害有机溶剂的残留量进行了同时测定。该方法以乙酸乙酯为萃取溶剂,45℃下超声萃取皮革及其制品中残留的有害有机溶剂,萃取液经固相萃取柱净化后进行气相色谱-质谱/选择离子监测法分析,外标法定量。结果表明,在信噪比(S/N)为10的条件下,乙二醇二丁醚(EGDBE)、三乙二醇二甲醚(TEGDME)、二乙二醇单丁醚(DEGBE)和三乙二醇单乙醚(TEGEE)的定量下限均为50μg/kg,N-甲基乙酰胺(MA)和N-甲基甲酰胺(MF)的定量下限均为150μg/kg,甲酰胺的定量下限为300μg/kg,其余14种组分的定量下限均为100μg/kg。在3个不同加标水平下,方法的平均加标回收率为82.1%~94.9%,相对标准偏差(RSD,n=9)为1.6%~4.8%。该方法简单快捷,灵敏度高,可用于皮革及其制品中有害有机溶剂残留量的测定。     

气相色谱-串联质谱法同时测定锂离子电池电解液中13种有机磷阻燃剂的含量

建立了一种可同时测定锂离子电池电解液中13种有机磷阻燃剂含量的气相色谱-串联质谱分析方法,以乙酸乙酯为萃取溶剂,超声萃取锂离子电池电解液中的有机磷阻燃剂,萃取液经浓缩、定容、过滤后进行气相色谱-串联质谱分析,外标法定量。结果显示,13种有机磷阻燃剂在一定浓度范围内线性良好,相关系数不低于0.999 3,方法的检出限(S/N=3)为0.3～30μg/kg,定量下限(S/N=10)为1～100μg/kg。在低、中、高3个加标水平下的平均回收率为80.4%～94.6%,相对标准偏差(RSD)为3.8%～10%。该方法简单快捷,灵敏度高,定量下限低,可满足锂离子电池电解液中有机磷阻燃剂含量日常检测需要。     

QuEChERS/GC-MS/MS测定人参中41种农药残留

建立了QuEChERS结合气相色谱-串联质谱(GC-MS/MS)测定人参中41种农药残留的分析方法,采用选择反应监测(SRM)模式,外标法定量,并考察了Original、Acetate和Citrate 3种QuEChERS前处理方法对人参基质中目标农药的提取效率和净化效果。结果表明,采用Original QuEChERS前处理方法时,41种农药在一定浓度范围内的线性良好,相关系数(r)大于0.995,方法的检出限(LOD,S/N=3)为2.0～6.0μg/kg,定量下限(LOQ,S/N=10)为5.0～20.0μg/kg。在10、20、100、200μg/kg 4个加标水平下的回收率为86.7%～115%,相对标准偏差(RSD)均小于15%。该方法样品前处理简单、高效、准确、灵敏,适用于人参中多农药残留的筛选与测定。     

土壤中13种磺酰脲类除草剂多残留的超高效液相色谱-串联质谱法测定

建立了超高效液相色谱-串联质谱法同时检测土壤中13种磺酰脲类除草剂多残留量的方法。样品经磷酸缓冲液(pH7.8)-甲醇(体积比1∶1)振荡提取,Oasis HLB固相萃取小柱净化后,采用多反应监测模式测定,外标法定量。13种磺酰脲类除草剂在5～200μg/L范围内线性关系良好,相关系数为0.999 1～0.9999。13种除草剂在5、20μg/kg水平下的平均加标回收率为89%～103%,相对标准偏差为1.1%～11.2%。方法的检出限(S/N=3)为0.020～0.092μg/kg,定量下限(S/N=10)为0.07～0.31μg/kg。     

微波辅助衍生化/气相色谱串联质谱同时测定猪肝与猪肾中4种巴比妥药物残留

采用气相色谱-离子阱串联质谱(GC-MS/MS)同时测定猪肝和猪肾中4种巴比妥类药物(巴比妥、异戊巴比妥、司可巴比妥钠和苯巴比妥)的残留量。残留药物用乙腈超声提取,浓缩后用5 mL 0.1 mol/LK2HPO4(pH 7.4)溶解,采用C18SPE柱净化,正己烷-乙酸乙酯(7∶3)洗脱,经CH3I微波辅助衍生化,甲基化产物经TR-5MS毛细管柱分离,在MS/MS模式下测定,外标法定量。方法在5～100μg/L范围内线性良好,相关系数r>0.99,4种巴比妥药物的检出限(LOD,S/N≥3)在猪肝中不高于0.65μg/kg,猪肾中不高于1.00μg/kg。定量下限(LOQ,S/N≥10)在猪肝中不高于2.20μg/kg,猪肾中不高于3.35μg/kg。4种药物的加标回收率为68%～90%,相对标准偏差(RSD)均不高于10%。方法可以准确监测动物组织中的巴比妥类药物残留。     

超高效液相色谱-串联质谱法测定葡萄干中27种农药残留

建立了同时快速检测葡萄干中氨基甲酸酯类杀虫剂、三唑类杀菌剂及其他杀菌剂、杀虫剂等27种农药的超高效液相色谱-串联质谱法(UPLC-MS/MS)。样品采用0.1%冰乙酸-乙腈溶液直接提取,QuEChERS方法净化,电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测,基质匹配曲线外标法定量。结果表明:27种农药在5～100μg/kg的浓度范围内线性良好(r≥0.993),在10、20、50μg/kg加标水平下,27种农药的平均回收率分别为60%～97%、62%～97%和64%～99%;相对标准偏差(RSD)分别为3.0%～13.0%、1.6%～9.6%和3.3%～9.6%,方法的定量下限(信噪比S/N≥10)为10μg/kg。该方法简便、快速、灵敏、准确,适于葡萄干中多种农残的确证和定量测定。     

QuEChERS/超高效液相色谱-串联质谱法同时测定水产品中四溴双酚A与六溴环十二烷

建立了同时测定水产品中四溴双酚A(TBBPA)和六溴环十二烷(HBCD)的超高效液相色谱-串联质谱方法。样品前处理采用QuEChERS方法,均质生物样品用水分散后加乙腈提取,经C_(18)分散固相萃取净化。采用CORTECS~?C_(18)色谱柱(4.6 mm×100 mm×2.7μm)分离,以甲醇-水为流动相进行梯度洗脱,流速为0.7 mL/min。采用电喷雾离子源,在负离子模式下以多反应监测(MRM)方式检测。结果表明,TBBPA和3种HBCD单体在0.5～500μg/L范围内线性良好,相关系数(r)大于0.998,检出限(LOD,S/N=3)和定量下限(LOQ,S/N=10)分别为0.04～0.16μg/kg和0.12～0.55μg/kg。在5、20、50μg/kg加标水平下的平均回收率为74.0%～121%,相对标准偏差(RSD)为0.20%～23%。该方法操作简单、快速、重现性好,适用于水产品中TBBPA和HBCD的快速检测。     

液相色谱-串联质谱法测定食品接触材料中28种初级芳香胺的迁移量

建立了液相色谱-串联质谱法(LC-MS/MS)同时测定食品接触材料中28种初级芳香胺(PAAs)迁移量的方法。采用C3色谱柱,以甲醇-水为流动相,梯度洗脱分离,在电喷雾正离子模式下以多反应监测(MRM)方式检测,外标法定量。28种PAAs检出限(LOD,S/N=3)和定量限(LOQ,S/N=10)分别为0.02～0.3μg/kg和0.1～1.0μg/kg;在1.0～1000μg/L浓度范围内线性良好,相关系数大于0.9915;加标浓度在1.0～100μg/kg的回收率为77.8%～105.3%;相对标准偏差(RSD)为4.5%～11.8%。本方法操作简便、快速、准确、灵敏度高,能满足相关测定要求。     

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.     

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.     

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.     

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.     

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.