动物源性食品中五种氟喹诺酮类药物残留量的同时测定

建立了一种测定动物源性食品中5种氟喹诺酮类药物残留量的高效液相色谱法。样品经酸性乙腈提取,正己烷液-液分配净化,0.01 mol/L四丁基溴化铵溶液溶解残渣,过微孔滤膜,采用高效液相色谱附荧光检测器检测,外标法定量。氧氟沙星、环丙沙星、恩诺沙星线性范围为0.002~0.200μg/mL;诺氟沙星、达氟杀星线性范围为0.001~0.100μg/mL,5种氟喹诺酮类药物的相关系数为0.99901~0.99917。在0.002~0.040 mg/kg范围内,样品加标平均回收率在79.6%~97.5%之间,相对标准偏差为2.8%~15.3%。方法的检出限氧氟沙星、环丙沙星、恩诺沙星为0.004 mg/kg,诺氟沙星、达氟沙星为0.002 mg/kg。     

高效液相色谱法检测冷冻烤鳗中恩诺沙星等药物残留

论述了高效液相色谱法检测冷冻烤鳗中恩诺沙星、环丙沙星、诺氟沙星等合成抗菌剂残留的方法。样品以乙腈为提取剂,经脱脂、浓缩、净化,用流动相溶解。高效液相色谱荧光检测器测定。各标准曲线线性范围为0.005～1.000mg·kg-1,回收率为86.2%～92.3%,检出限分别为1,2,2μg·kg-1。     

铁络合光度法测定氧氟沙星和诺氟沙星含量

研究了氧氟沙星、诺氟沙星与Fe(III)在室温下的络合反应.在酸性介质中,氧氟沙星、诺氟沙星与Fe(III)形成的黄色配合物最大吸收波长为436nm;氧氟沙星和诺氟沙星的浓度分别在2.24~192mg/L和8.0~248mg/L范围内与体系的吸光度呈良好的线性关系,其线性回归方程分别为:A=0.009 06+0.005 7 c(c,mg/L;r=0.999 3;氧氟沙星)和A=0.001 23+0.003 04 c(c,mg/L;r=0.999 8;诺氟沙星),方法的检出限分别为0.41和0.76mg/L.对浓度均为64.0mg/L的氧氟沙星和诺氟沙星平行测定11次,其相对标准偏差分别为0.6%和0.8%.应用拟定的方法对氧氟沙星和诺氟沙星药物制剂中主成分的含量进行了测定,回收率在99.7%~104.7%范围内.     

液相色谱-串联质谱法检测水产品中15种喹诺酮类药物残留量

建立了液相色谱-串联质谱技术同时检测水产品中15种喹诺酮类药物(氟罗沙星、氧氟沙星、依诺沙星、诺氟沙星、环丙沙星、恩诺沙星、洛关沙星、单诺沙星、奥比沙星、双氟沙星、沙拉沙星、司帕沙星、口恶喹酸、萘啶酸、氟甲喹)残留量的方法.试样中残留的喹诺酮类药物采用乙腈提取,提取液经正已烷液液分配脱脂后,以强阳离子固相萃取小柱净化,液相色谱.串联质谱法测定.对液/质分离条件与样品前处理条件进行了优化,并对喹诺酮类药物在分析过程的稳定性进行了研究.15种喹诺酮类药物在1.0～100 μg/L范围内线性关系良好,相关系数为0.9924～0.9992.在0.002～0.04 mg/kg浓度范围内,平均加标回收率在79.9%～93.8%;相对标准偏差为4.8%～14.6%.方法可满足水产品中喹诺酮类药物多残留检测与确证的需要.     

化妆品中7种氟喹诺酮类药物的反相高效液相色谱法测定

建立了反相高效液相色谱同时测定膏霜类化妆品中7种氟喹诺酮类药物(诺氟沙星、培氟沙星、环丙沙星、丹诺沙星、恩诺沙星、沙拉沙星、双氟沙星)的方法.样品先用乙腈-水(0.1%甲酸)(体积比5 ∶ 95)溶液提取,经正己烷脱脂净化后用反相高效液相色谱法测定.添加水平为1.0 ～10.0 mg/kg时,回收率为87% ～108%,相对标准偏差为2.3% ～5.8%.结果表明,该法操作简便、灵敏、准确,适用于膏霜类化妆品中氟喹诺酮类药物的测定.     

高效液相色谱法测定饲料中辛硫磷残留量

提出了高效液相色谱法测定饲料中辛硫磷残留量的方法。样品经乙酸乙酯提取,氨基固相萃取小柱净化,所得净化液以反相C18色谱柱为分离柱,以乙腈-水(65+35)混合溶液为流动相,在检测波长280nm处进行测定。辛硫磷的质量浓度与其峰面积在0.10～0.50mg·L-1范围内呈线性关系,方法的检出限(3S/N)为0.10mg·kg-1。加标回收率在80.0%～88.2%之间,测定值的相对标准偏差(n=5)在1.6%～6.5%之间。     

高效液相色谱法检测水产品中磺胺类和乙胺嘧啶药物残留

用高效液相色谱法检测水产品中磺胺类、乙胺嘧啶等合成抗茵剂残留.样品以乙腈、二氯甲烷、乙酸乙酯以体积比2比1比1为提取剂,经脱脂、净化、浓缩,用流动相溶解.用高效液相色谱法紫外检测器测定.通过梯度洗脱将7种磺胺类、乙胺嘧啶进行分离.各标准曲线线性范围为0.05～2.0 mg·L-1,相关系数为0.983 7～0.997 5,回收率分别为62.2%～88.6%,相对标准偏差为5.85%～8.12%(n=7),检出限(S/N=3)为10～50 μg·kg-1.     

多壁碳纳米管分子印迹固相萃取柱的制备及牛奶中三种氟喹诺酮的残留测定

建立了以恩诺沙星为假模板的多壁碳纳米管分子印迹固相萃取柱-HPLC法同时测定牛奶中三种氟喹诺酮氧氟沙星、诺氟沙星、环丙沙星残留的方法。牛奶样品经碳酸钠、乙腈沉淀蛋白后,用乙酸钠-盐酸体系调p H为3.0,经自制的多壁碳纳米管分子印迹固相萃取柱(MWCNTs-MISPE)净化萃取后,用高效液相色谱仪测定氧氟沙星、诺氟沙星、环丙沙星的含量。3种化合物在20.00-1000 ng/m L浓度范围线性关系良好,相关系数均大于0.9998,3个添加水平的回收率在82.3%-99.4%,日内和日间精密度小于20%。本文首次将自制的多壁碳纳米管分子印迹固相萃取柱应用于牛奶中的氟喹诺酮类化合物净化与富集,3份市售牛奶中氧氟沙星,诺氟沙星和环丙沙星含量均低于欧盟标准。     

高效液相色谱法测定水产品中7种兽药残留量

提出了高效液相色谱法同时测定水产品中呋喃唑酮、噁喹酸、萘啶酸及4种磺胺类药物等7种兽药残留量的方法。样品经乙腈提取,正己烷脱脂,用中性氧化铝柱和C18固相萃取柱进行分离及净化。以Symmetry C18色谱柱为分离柱,以不同体积比混合的乙腈与0.08mol.L-1乙酸溶液为流动相进行梯度洗脱,紫外检测器于波长265nm处检测。7种兽药的质量浓度与其峰面积均在0.05～1.0mg.L-1范围内呈线性关系,检出限(3S/N)为0.01～0.04mg.kg-1。方法的回收率在68.2%～97.3%之间,相对标准偏差(n=6)在1.6%～14%之间。     

超高效液相色谱法测定水产品中3种喹诺酮类药物残留量

提出了应用超高效液相色谱法测定水产品中诺氟沙星、环丙沙星和恩诺沙星等3种喹诺酮类药物残留量的方法。样品采用酸化乙腈提取,减压蒸干后用流动相溶解,经正己烷脱脂。以ACQUITY UPLCTMBEH C18色谱柱为分离柱,以乙腈与甲酸(0.1+99.9)溶液按体积比10比90混合作为流动相,在激发波长280nm、发射波长450nm的条件下进行荧光光度检测。3种药物的线性范围均为1.25～500μg.L-1,检出限(3S/N)均为0.1μg.kg-1,测定下限(10S/N)均为0.3μg.kg-1。以鲳鱼、对虾、河蟹等空白样品为基体做加标回收试验,测得回收率均大于80%。     

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.     

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.     

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.