液相色谱-串联质谱法测定食用植物油中的棉酚

建立了食用植物油中棉酚的液相色谱-串联质谱（LC-MS/MS）分析方法。待测物经无水乙醇涡旋振荡提取,C18色谱柱分离,以乙腈和0.1%（v/v）甲酸水溶液为流动相进行梯度洗脱,LC-MS/MS测定,外标法定量。方法的测定低限（S/N>10）为1 mg/kg;在添加浓度为1、2和200 mg/kg水平下,棉酚的加标回收率为87.4%~100%,相对标准偏差为3.9%~12.2%。结果表明,本方法灵敏度高,测定结果准确,回收率稳定,可用于食用植物油中棉酚残留的确证检测。     

超高效液相色谱-串联质谱测定饲料中镇静剂类和β-受体激素类药物残留

采用超高效液相色谱-串联质谱技术,建立了饲料中8种镇静剂类和15种β-受体激素类药物残留的分析检测方法。样品采用乙腈-1%(体积分数)三氯乙酸水溶液(7∶3,v/v)提取,目标物通过阳离子固相萃取柱净化,经Agilent Zorbax Eclipse Plus C_(18)色谱柱(100 mm×3.0 mm,1.8μm)分离,液相色谱-串联质谱进行检测,标准曲线内标法定量。结果表明:23种目标物在2.0~200.0μg/L内线性关系良好(r20.99)。在饲料样品基质中,目标化合物在5.0、10、50μg/kg 3个加标水平下的平均回收率为75.1%~102.4%,相对标准偏差(RSD)为4.3%~14.3%(n=6)。该方法净化效率高,适用范围广,可用于饲料中镇静剂类和β-受体激素类药物残留筛查和检测。     

液相色谱-串联质谱法测定育肥猪配合饲料中的阿奇霉素

通过对提取溶剂、净化方法及色谱-质谱条件的优化,建立了配合饲料中阿奇霉素(AZM)的液相色谱-串联质谱测定方法。样品经乙腈超声波提取,MCX固相萃取柱净化,BDS Hypersil C_(18)(2.4μm,100 mm×2.1 mm)色谱柱分离,以甲醇-0.05 mol/L乙酸铵水溶液为流动相梯度洗脱,正离子模式电离,多反应监测模式检测,同位素内标法定量。在优化条件下,AZM在1~250μg/L范围内线性关系良好,相关系数(r~2)为0.999 1,检出限(S/N≥3)为2.8μg/kg,定量下限(S/N≥10)为8.4μg/kg;在0.5,1,5,10 mg/kg加标水平下,回收率为87.0%~106.6%,批内相对标准偏差为0.58%~5.4%,批间相对标准偏差为3.1%~5.4%。该方法准确、灵敏,选择性强,基质干扰小,可用于配合饲料中AZM的测定。     

凝胶渗透色谱-高效液相色谱-串联质谱法同时测定烟草中3种抑芽剂残留

建立了用凝胶渗透色谱净化-液相色谱-串联质谱分析烟草中3种抑芽剂残留的方法。卷烟中的待测抑芽剂组分用V(乙酸乙酯)∶V(环己烷)=1∶1超声提取后通过凝胶渗透色谱净化;凝胶色谱柱为Biobeads S-X3玻璃柱(50 g,400 mm×25 mm),流动相为V(乙酸乙酯)∶V(环己烷)=1∶1溶液,流速5 mL/min;收集第10~25 min流出的液体用液相色谱色谱-三重四极杆串联质谱仪测定。在0.5~100 ng/mL的质量浓度范围内,各种抑芽剂标准溶液的线性相关系数均大于0.99。在样品中添加3种抑芽剂(添加水平为5,20,100μg/kg)的混合标准溶液,平均回收率在86.2%~108.4%之间,3种抑芽剂的RSD在1.1%~7.5%之间;方法的检测限在0.01~0.06μg/kg之间。     

高效液相色谱-串联质谱法快速测定水产品中19种喹诺酮类药物残留

应用PRiME HLB净化技术,采用超高效液相色谱-串联四极杆质谱(UPLC-MS/MS),建立了水产品中19种喹诺酮类药物残留的检测方法。对样品的净化、浓缩、液相色谱分离及串联质谱等相关检测参数进行了优化。样品经80%乙腈水溶液提取,PRiME HLB固相萃取柱净化,在ACQUITY BEH C_(18)色谱柱(1.7μm,2.1 mm×100 mm)上以甲醇和5 mmol/L乙酸铵水溶液(含0.1%甲酸)为流动相梯度洗脱,液相色谱-串联质谱MRM方式进行定量分析。结果表明:各组分在各自浓度范围内线性关系良好,平均回收率为72.1%~119.9%,相对标准偏差为2.4%~15.6%,检出限均为0.5μg/kg,定量下限均为1.5μg/kg。该方法用于水产品中喹诺酮类药物残留的检测,具有准确、快速、简便、灵敏度高等优点,为水产品中喹诺酮类药物残留的测定提供了新途径。     

QuEChERS结合高效液相色谱-串联质谱法测定饲料中的18种β-兴奋剂

建立了饲料中克仑特罗、莱克多巴胺、喷布特罗、妥布特罗等18种β-兴奋剂的QuEChERS结合高效液相色谱-串联质谱的检测方法。饲料样品加水分散后经4%(v/v)氨水乙腈提取,加入25 mg十八烷基硅烷(C18)和50mg N-丙基乙二胺(PSA)吸附剂分散固相萃取净化后,以高效液相色谱-串联质谱进行定性和定量分析。采用Agilent Zorbax Eclipse XDB-C18(50 mm×4.6 mm,1.8μm)分析柱,以甲醇-0.1%(v/v)甲酸水溶液为流动相进行梯度洗脱,串联质谱在多反应监测(MRM)正离子模式下进行检测,基质外标法定量。结果表明,18种待测物在质量浓度为5~200μg/L范围内线性关系良好,相关系数为0.9912~0.9995;在0.05、0.1、0.5 mg/kg 3个浓度加标水平下,饲料中18种β-兴奋剂的平均回收率为78.4%~107.1%,相对标准偏差(RSD)为3.5%~12.3%,定量限(以信噪比≥10计)均为0.05 mg/kg。该方法准确、灵敏,前处理简单,可作为饲料中克仑特罗等18种β-兴奋剂筛选和确认的检测方法。     

凝胶渗透色谱-固相萃取净化/气相色谱-串联质谱法测定动物性食品中167种农药残留

建立了肉类、水产类等动物性食品中167种农药残留的气相色谱-串联质谱检测方法。样品匀浆后,采用乙腈提取,以凝胶渗透色谱和Carb-NH2萃取柱联合净化,气相色谱-串联质谱检测,外标法定量。167种农药的响应在1~200μg/L质量浓度范围内线性良好,相关系数在0.994以上,各农药的检出限为0.3~3μg/kg,定量下限为1~10μg/kg。以猪肉样品作为代表性基质,进行0.01,0.04 mg/kg 2个水平的加标回收实验,回收率为66.4%~111.5%,相对标准偏差为1.3%~17.8%。本方法准确可靠,灵敏度高,样品净化效果好,能够满足动物性食品中农药多残留的痕量分析要求。     

基于QuEChERS提取的HPLC-MS/MS法测定禽肉中的利巴韦林与金刚烷胺

建立了液相色谱-串联质谱(HPLC-MS/MS)同时测定禽肉中利巴韦林和金刚烷胺的检测方法。禽肉样品用1%(体积分数)三氯乙酸水溶液-甲醇(1∶1,体积比)提取,经PCX固相萃取柱和QuEChERS方法净化后,以含5 mmol/L乙酸铵水溶液与甲醇为流动相梯度洗脱,BEH HILIC(2.1 mm×100 mm,1.7μm)色谱柱分离,电喷雾正离子模式电离,多级反应监测(MRM)模式进行检测,内标法定量。结果表明,利巴韦林和金刚烷胺在0.50~200μg/L范围内呈良好线性,相关系数均大于0.997。两种目标分析物的方法检出限(S/N≥3)分别为0.30μg/kg和0.15μg/kg,定量下限(S/N≥10)分别为1.00μg/kg和0.50μg/kg,样品在其1倍、2倍、10倍定量下限3个加标水平下的日内回收率为92.5%~104.7%,相对标准偏差(RSD)为3.4%~7.8%;日间回收率为93.3%~106.0%,RSD为6.0%~10.7%。该方法灵敏、简便、准确,可用于禽肉中利巴韦林和金刚烷胺残留的同时检测。     

河豚鱼、鳗鱼和烤鳗中角黄素残留的超高效液相色谱法测定和超高效液相色谱-串联质谱法确证

建立了河豚鱼、鳗鱼和烤鳗中角黄素残留的超高效液相色谱测定方法和超高效液相色谱-串联质谱确证方法。样品用抗氧化剂焦性没食子酸保护,乙腈均质提取,正己烷液-液分配净化,超高效液相色谱-紫外检测器测定,外标法定量,超高效液相色谱-串联质谱法确证。测定方法采用BEHC18色谱柱(50 mm×2.1 mm,i.d.1.7μm),流动相为V(0.1%的甲酸)∶V(乙腈)=3∶97,检测波长470 nm。实验结果表明,角黄素在0.05~2.0 mg/L范围内线性关系良好(r=0.9999),在空白样品中,添加低、中、高3个浓度水平(0.05,0.1,1.0 mg/kg),角黄素的回收率均在82.52%~96.96%之间,相对标准偏差为6.9%~15%。方法的检出限(LOD)为0.02 mg/kg,定量限(LOQ)为0.05 mg/kg。串联质谱确证方法采用电喷雾(ESI)离子源,在正离子模式下以多反应监测(MRM)扫描方式检测,定性离子对565.5/203.2和565.5/133.1,定量离子对565.5/203.2。     

高效液相色谱-串联质谱法测定卷烟中的甘草酸

建立了高效液相色谱-串联质谱法(HPLC-MS/MS)测定卷烟中甘草酸的分析方法。采用甲醇-5mmol/L醋酸铵水溶液(4∶1)为萃取溶剂,经Agilent ZORBAX Eclipse XDB-C18色谱柱(2.1 mm×150 mm,3.5μm)分离后,串联质谱多反应离子监测模式(MRM)检测,外标法定量。甘草酸在0.05~2.50 mg/L浓度范围内线性良好,相关系数大于0.999 4,方法的定量下限为4.8 mg/kg;回收率为89.1%~105.0%,日内、日间相对标准偏差(RSD)均不大于5%。     

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.