气相色谱-质谱法同时测定动物内脏中的14种酞酸酯类环境激素残留

开展了动物内脏中14种酞酸酯类（PAEs）环境激素残留的气相色谱-电子轰击离子源/质谱（GC-EI/MS）的分析方法研究。优化与选择了动物内脏样品的前处理条件,动物内脏样品经正己烷/二氯甲烷（1/1,v/v）混合提取剂超声提取、Florisil硅藻土固相萃取柱净化与乙酸乙酯/正己烷（2/3,v/v）混合洗脱剂洗脱和浓缩后,以邻苯二甲酸二苯基酯（DPhP）为内标物,采用GC-EI/MS的选择离子监测方式（SIM）进行定性和定量分析。当猪肝样品的加标浓度水平为100、200、400 μg/kg时,加标回收率为：60%~110%,相对标准偏差为：0.78%~10.3%;除邻苯二甲酸二（2-甲氧基乙基）酯（DMEP）与邻苯二甲酸二（2-乙氧基乙基）酯（DEEP）的检测限（MDL）分别为3.30与2.25 μg/kg外,其余的12种PAEs的MDL ≦ 1.74 μg/kg;线性范围为50 ~ 800 μg/kg,相关系数都大于0.9994。此分析方法成功地应用于6种动物内脏中14种痕量PAEs残留的分析。     

超高效液相色谱-串联质谱法测定蔬菜和水果中腈吡螨酯残留量

建立了蔬菜和水果中腈吡螨酯残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法。样品经乙腈均质提取,混合使用乙二胺-N-丙基硅烷(PSA)和C18两种基质分散净化剂净化,净化液过膜后直接进行UPLC-MS/MS检测。通过考察腈吡螨酯在不同果蔬样品中的基质效应发现,采用UPLC-MS/MS检测蔬菜和水果中腈吡螨酯残留量时,腈吡螨酯在不同种类样品中存在不同程度的基质减弱效应,采用空白基质溶液稀释标准建立校正的标准曲线外标法定量以消除基质效应。结果表明,腈吡螨酯在0.05~10μg/L浓度范围内具有良好的线性关系,相关系数不低于0.999 6。在0.000 05~2 mg/kg范围内进行加标回收率实验,平均回收率为81.1%~99.3%,相对标准偏差为4.7%~9.3%,方法的定量下限为0.043μg/kg,检出限为0.013μg/kg。     

分散固相萃取结合HPLC-MS/MS检测鸡蛋中16种全氟化合物

建立了分散固相萃取净化结合HPLC-MS/MS测定鸡蛋中16种全氟化合物(Perfluorinated compounds,PFCs)的方法。样品经乙腈40℃下超声萃取,氮吹浓缩,石墨化碳黑分散萃取净化后,采用HPLCMS/MS进行测定,基质曲线-内标法定量。结果显示,16种PFCs在0.50~10.0μg/L浓度范围内呈良好线性,相关系数(r)为0.996 2~0.999 9,检出限为0.001~0.093μg/kg,定量下限为0.003~0.310μg/kg。在0.5,1.0,2.0μg/kg 3个加标浓度水平下,16种PFCs的加标回收率为79%~125%,相对标准偏差(RSDs,n=6)为0.26%~14%。该方法具有净化效果好、定量准确、灵敏度高的特点,适用于鸡蛋样品中16种常见全氟化合物的快速确认和准确定量。     

动物肝脏中九种多溴联苯醚残留量的GC—NCI／MS分析

建立了动物肝脏中9种PBDEs残留量的气相色谱-负化学离子源/质谱(GC-NCI/MS)的分析方法。动物肝脏样品经V(正己烷)∶V(丙酮)=1∶1超声辅助提取,中性与酸性硅胶层析柱净化和V(正已烷)∶V(CH2Cl2)=1∶1洗脱和浓缩后,以PCB-103为内标物,采用GC-NCI/MS的选择离子监测方式(SIM)对其中的9种PBDEs残留量进行了定性与定量分析。当动物肝脏空白样品的加标质量浓度为5.0、20.0μg/kg(PBDE-183为6.0、24.0μg/kg)时,9种PBDEs的平均加标回收率为75.1%~88.2%,相对标准偏差为3.3%~7.9%,方法检出限均小于0.07μg/kg;线性范围除PBDE-183为0.12~600.0μg/kg外,其余8种PBDEs为0.1~500.0μg/kg,相关系数都大于0.9993。所建立的分析方法已用于5种动物肝脏的8个样品中9种PBDEs残留量的分析。     

UPLC-MS/MS检测鸡蛋中16种磺胺类药物残留

采用UPLC-MS/MS建立了鸡蛋中16种磺胺类药物残留检测方法。样品经过磷酸盐缓冲液提取、正己烷分步去脂,氮吹、MCX柱净化后,经Acquity UPLC BEH(100 mm×2.1 mm,1.7μm)分离,以甲醇和0.1%加酸水溶液为流动相进行梯度洗脱,16种化合物能在11 min完全分离,方法的定量限均低于1.0μg/kg,在2.5~100μg/L范围内,16种磺胺类药物线性良好,相关系数均在0.99以上;通过2,10,40μg/kg加标回收实验表明,回收率为62.7%~96.1%,RSD为2.1%~15%。方法满足鸡蛋中磺胺类药物残留检测要求。     

超高效液相色谱-串联质谱法测定动物性食品中10种拟除虫菊酯类农药残留

建立了动物性食品中10种拟除虫菊酯类农药残留的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法。样品经冰乙酸-乙腈(1∶99,体积比)超声提取,低温冷冻除去大部分的油脂杂质后,再用Z-Sep~+和C_(18)净化。以0.1%甲酸水溶液(含5 mmol/L乙酸铵)和甲醇为流动相,经ACQUITY HSS T3色谱柱分离,采用电喷雾电离,多反应监测模式进行测定。结果表明,10种拟除虫菊酯在2.5~100μg/L范围内线性关系良好,相关系数均大于0.997,检出限为0.9~2.4μg/kg,定量下限为3.0~8.0μg/kg;在10、50、100μg/kg 3个加标水平下,空白样品的加标回收率为70.3%~120%,相对标准偏差(RSD)为1.2%~11.2%。该方法前处理简单、灵敏度高、准确性好,且在10 min内可完成检测,满足动物性食品中10种拟除虫菊酯农药残留的快速检测要求。     

超高效液相色谱-质谱联用法测定蔬菜中多杀霉素等4种农药残留

采用固相萃取/超高效液相色谱-串联质谱(SPE/UPLC-MS/MS)建立了多种蔬菜中4种农药残留量的分析方法,并对净化方法、色谱及质谱条件进行优化。蔬菜样品经乙腈提取、提取液经盐析后,取上清液经PC/NH2(或NH2)固相萃取小柱净化,浓缩后,用甲醇定容并过膜,采用超高效液相色谱-串联质谱多反应监测(MRM)正离子模式进行外标法定量测定。结果表明,4种农药在5~500μg/L范围内线性关系良好(r≥0.999 2),在8种蔬菜中的检出限和定量下限分别为0.033~0.167μg/kg和0.10~0.50μg/kg。在10,50,250μg/kg 3个浓度加标水平下,4种农药的回收率为70.9%~123.4%,相对标准偏差(RSD)小于15%。方法准确、灵敏、简单、快速,适用于多种蔬菜中多杀霉素等4种农药残留的同时测定。     

基质固相分散-气相色谱-离子阱串联质谱法分析牛奶中有机磷农药

将改进的基质固相分散法与GC-MS/MS分析方法结合应用于牛奶中13种有机磷农药残留的同时分析。优化各样品前处理参数后,样品与分散剂中性氧化铝研磨后,采用乙腈超声提取。过滤浓缩后以灭线磷为内标物,采用GC-MS/MS进行定性与定量分析。从样品前处理到分析约需1 h,当样品的加标水平为50、200μg/kg时,平均加标回收率为70.4%~117.6%,相对标准偏差为0.8%~19%;除倍硫磷和毒死蜱的检测限分别为5.60和9.35μg/kg外,其它11种有机磷农药的检测限均在0.37~3.77μg/kg之间;线性范围为25~500μg/kg,相关系数均大于0.9949。     

气相色谱-三重四极杆串联质谱结合QuEChERS测定三七中有机磷农药残留

建立了改良的QuEChERS样品前处理法,结合气相色谱-三重四极杆串联质谱(GC-MS/MS)同时测定三七中18种有机磷农药残留的方法。样品经1%乙酸-乙腈提取,改良QuEChERS技术净化,利用GC-MS/MS采取多反应离子监测模式测定,基质匹配校准曲线外标法定量。18种有机磷农药残留在2.5~120.0μg/kg范围内线性良好,相关系数(R2)大于0.99;检出限为0.4~1.5μg/kg,定量限为0.8~2.5μg/kg。在3个加标水平(2.5,8.0,60.0μg/kg)下平均回收率为70.5%~118.9%,相对标准偏差为1.0%~9.8%。     

气相色谱-质谱法测定白酒中邻苯二甲酸酯

建立了白酒中15种邻苯二甲酸酯类化合物(PAEs)残留量的气相色谱-电子轰击离子源质谱(GC-EI/MS)测定方法。样品通过旋转蒸发除乙醇,正己烷超声提取,LC-Si SPE小柱净化,氮吹浓缩后进行气相色谱-质谱法分析。结果表明:该方法具有良好的线性关系,相关系数(r2)大于0.998,平均加标回收率为85.3%~103.1%,相对标准偏差为3.8%~8.8%,15种邻苯二甲酸酯(PAEs)的方法检出限(MDL)为0.011~0.041mg/L。该方法具有简单、快速、灵敏度高和定性定量准确等优点,满足各类白酒样品的分析要求。     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.