高效液相色谱-串联质谱联用测定富含淀粉食品中丙烯酰胺

以甲基阿烯酰胺作为内标物，用高效液相色谱／串联质谱（HPLC／MS／MS）法测定食品中的丙烯酰胺。均质后的食品样品，加入正己烷经液-液分配去除脂肪，用蒸馏水提取丙烯酰胺，Carrez试剂净化提取样品，净化液经离心后过0．45μm微孔滤膜，采用HPLC／MS／MS电喷雾电离（ESI），阳离子，多反应监测（MRM）模式检测，外标法定量。方法的线性范围为2～500μg／L，线性相关系数为0．9997，检出限为2μg／kg；高中低3个水平的加标回收率分别为99．4％、99．6％和98．4％；相对标准偏差（RSD）均小于7．8％。     

高效液相色谱/串联质谱法测定奶粉中的硝基呋喃代谢物

用高效液相色谱／串联质谱（LC—MS／MS）法同时测定奶粉中呋喃唑酮、呋喃它酮、呋喃西林和呋喃妥因的代谢物。盐酸水解奶粉中蛋白结合的代谢物，同时加入2-硝基苯甲醛（2-NBA），37℃过夜衍生化。加入硫酸锌，调pH值至7．0后，再加入亚铁氰化钾去除蛋白。后用乙酸乙酯提取，正己烷净化，分析物采用电喷雾电离正离子（ESI＋）、多反应监测（MRM）模式检测，内标法定量。在添加浓度0．5—2μg/kg范围内，内标法回收率为89．5％～110．3％；相对标准偏差（RSD）小于11，3％。5-马啉代甲基-3-氨基-2-恶唑酮（5-methylmorpholino-3-amino-2-oxazolidinone，AMOZ）、3-氨基-2-恶唑酮（3-amino-2-oxazolidinone，AOZ）方法检出限为0．05μg／kg，氨基脲（semicarbazide，SEM）、1-氨基-乙内酰胺（1-amino—hydantoin，AHD）为0．1μg/kg。     

固相萃取高效液相色谱-质谱法测定动物组织中硝基呋喃代谢产物

研究了对动物组织中4种硝基呋喃类代谢产物AOZ、AMOZ、SEM和AHD的自动固相萃取HPLC-MS分析方法，分别以2-氯苯甲醛和2-硝基苯甲醛作为衍生化试剂，分别用AMOZ-d5、AOZ-d4作内标，用ENSPE柱进行提取，以乙腈-0．1％甲酸为流动相，采用梯度洗脱，可在15min内将4种代谢产物完全分离并进行测定。回收率为85％-90％；检出限可达0．5μg／kg。采用两种衍生化方法可获得较多的定性确证信息。采用本方法研究了硝基呋喃在鸡饲养过程中的残留规律。     

同位素稀释气相色谱串联质谱法测定海产品中的苯并（α）芘的残留量

采用同位素稀释法结合固相萃取净化,建立了海产品中苯并（α）芘残留的气相色谱串联质谱（6C—MS／MS）检测方法。样品经乙腈一丙酮（体积比6：4）溶液提取,硅胶固相萃取净化,苯并（μ）芘用GC—MS／MS测定,同位素D12-苯并芘内标法定量。方法的平均回收率为93％-98％,相对标准偏差为6.2％～12．2％（n=6）,定量限为0．2μg／kg。用该方法测定FAPAS烟熏鱼有证标准样品,测定值与标准值一致。     

反相高效液相色谱／质谱法同时测定鸡肉中5种喹诺酮药物残留

采用反相高效液相色谱／四级杆串联质谱（RP-HPLC／MS／MS）同时测定鸡肉中的5种喹诺酮药物（quinolones，QNs）。均质后的鸡肉样品采用磷酸盐缓冲溶液和乙腈的混和溶液提取。提取液经正己烷液-液分配（LLP）去除脂肪后，用C18固相萃取（SPE）柱净化，氨化甲醇洗脱，洗脱液用氮气吹干，流动相定容后，分析物采用LC／MS／MS电喷雾电离（ESI），正离子，多反应监测（MRM）模式检测，外标法定量。在添加浓度2．5～10μg/kg范围内，5种QNs的回收率在79．8％～95．1％之间；相对标准偏差（RSD）均小于11．7％。环丙沙星、丹诺沙星、恩诺沙星检出限（LOD）为0．5μg／kg，沙托沙星为1．0μg／kg，氟甲喹为0．1μg／kg。     

液相色谱-串联质谱法对动物源性食品中14种苯二氮革类药物及其代谢物残留量的同时检测

建立了液相色谱-串联质谱（LC—MS／MS）同时检测动物源性食品中14种苯二氮革类药物及其代谢物残留量的测定方法。在pH5．2乙酸铵缓冲溶液中药物残留经酶解后,用氨水调节pH值大于9．5。溶液经乙酸乙酯-异丙醇（体积比5：1）提取和阳离子交换柱（MCX）净化,并用多反应监测技术所确定的定性离子对检测物进行定性和同位素内标法定量。方法的定量下限为1．0μg／kg,线性范围为1．0～20．0μg/L,各基质的加标平均回收率为64％～117％,相对标准偏差为3．6％～12．3％。     

高效液相色谱-串联质谱法测定鸡组织中的喹烯酮标示残留物

采用液相色谱-串联质谱（HPLC—MS／MS）法测定鸡组织（肌肉、肝、肾）中喹烯酮标示残留物3-甲基喹噁啉-2-羧酸的含量。组织匀浆样品经碱水解、液液萃取,采用HPLC—MS／MS电喷雾电离（ESI）,正离子模式,多反应监测（MRM）,以喹噁啉-2-羧酸为内标进行定量。检出限为5μg／kg。     

高效液相色谱-电喷雾三级四极杆质谱测定鸡肉组织中氯霉素残留的研究

建立了鸡肉组织中氯霉素残留的液相色谱-电喷雾质谱联用(LC—ESI—MS—MS)测定法。采用微量化前处理方法,省去固相萃取步骤,以m／z321．0为母离子,m／z152．1、257．0和194．1为子离子,采用多反应监测(MRM)负离子模式对鸡肉组织中的氯霉素残留进行检测、方法的检出限为0．010μg／kg(S／N≥3),定量下限为0．10μg／kg,线性范围为0．100～1．00μg／L,加标回收率为74．3％～84．0％,相对标准偏差(n=6)为7．9％～12．7％。该法具有操作简便、有机试剂消耗量少、测定周期短等优点。     

固相萃取-气相色谱-质谱法测定猪组织中沙丁胺醇残留量

建立了动物组织中沙丁胺醇残留量固相萃取-气相色谱-质谱分析方法。动物组织样品经过葡萄糖醛甙酶酶解后调节pH至9．5，然后用异丙醇／乙酸乙酯混合溶剂液液分配去除杂质，旋转浓缩后用乙酸铵缓冲溶液溶解经SCX固相萃取（SPE）柱净化，洗脱液经氮气吹干后用双三甲基硅基三氟乙酰氨（BSTFA）衍生，采用选择离子模式（86、350、369、440）进行测定，外标法定量。检出限为0．10μg/kg。在添加浓度0．5～5．0μg/kg范围内，平均添加回收率在66．4％～82．4％，相对标准偏差（批内）（CV）在3．5％～5．9％之间；批间（CV）在2．2％～4．8％之间。衍生物的峰面积与样品浓度在0．002～0．50mg／L范围内呈良好的线性关系，线性回归系数大于0．999。     

气相色谱-质谱法测定肝脏组织中盐酸克伦特罗和盐酸菜克多巴胺

建立了同时测定动物肝组织中盐酸克伦特罗和盐酸莱克多巴胺残留量的固相萃取-气相色谱-质谱分析方法。动物肝组织样品在碱化的条件下用乙酸乙酯和异丙醇混合溶剂提取，提取液浓缩后用乙酸乙酯溶解，然后再用稀盐酸反萃取去除脂肪，调pH值后经SCX固相萃取（SPE）柱净化，洗脱液经氮气吹干后经双三甲基硅基三氟乙酰氨（BSTFA）衍生，采用选择离子模式（盐酸克伦特罗：86、212、262、277，盐酸莱克多巴胺：163、192、234、250）进行测定，外标法定量。盐酸克伦特罗和盐酸莱克多巴胺的检出限分别为0．30和1．00μg／kg。盐酸克伦特罗添加浓度在1．0～5．0μg／kg范围内，添加回收率为77．4％～88．3％；相对标准偏差（RSD）为3．1％～5．1％；盐酸莱克多巴胺添加浓度在4．0～20．0μg／kg，添加回收率为69．8％～82．1％；相对标准偏差（RSD）为3．5％～4．9％；衍生物的峰面积与被测物浓度分别在0．003～1．00mg／L和0．012～4．00mg／L范围内呈良好的线性关系，线性回归系数均大于0．999。     

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.