流动注射-化学发光法测定猪饲料中的吡喹酮

基于吡喹酮对Luminol-NaIO_4化学发光体系有较强的抑制作用,并结合流动注射分析技术,建立了测定吡喹酮的流动注射-化学发光(FI-CL)新方法。在最佳实验条件下,吡喹酮在4.0×10~(-8)～1.0×10~(-6) mol/L浓度范围内与相对化学发光强度呈良好的线性关系,该方法对测定吡喹酮显示出较高的灵敏度,检出限(LOD,3σ)为9.9×10~(-9) mol/L。对2.0×10~(-7) mol/L的吡喹酮平行测定11次,其相对标准偏差(RSD)为1.4%。采用该方法对猪饲料样品进行加标实验,回收率为98.5%～100%。该方法已经成功用于猪饲料样品中吡喹酮的测定。     

高效液相色谱-串联质谱法测定兔血浆中吡喹酮

建立了高效液相色谱-串联质谱法测定兔血浆中吡喹酮浓度。血浆样品经乙腈沉淀蛋白,以Waters XBridge C18柱(2.1×50 mm,3.5μm)进行色谱分离,流动相为乙腈-体积分数0.1%甲酸溶液,梯度洗脱分离,三重四级杆质谱仪进行电喷雾离子化和正离子多离子反应监测模式检测吡喹酮。吡喹酮在0.8~2000.0 ng/mL范围内线性关系良好,相关系数为0.9983,检出限为0.01 ng/mL,在加样量为1600.0,160.0,2.5 ng/mL的血浆样品中,吡喹酮的相对回收率为83.8%~104.8%,提取回收率为79.5%~96.5%,日内和日间RSD均小于6.4%。方法可用于吡喹酮血药浓度的测定。     

动物源性食品中吡喹酮残留量的LC-MS/MS测定

应用固相萃取液相色谱-串联质谱法(LC-MS/MS)技术建立了动物源性食品中吡喹酮药物残留的检测方法。用乙酸乙酯提取样品中的吡喹酮残留,提取液经碱性氧化铝小柱净化,LC-MS/MS测定,在10~40μg/kg范围内添加回收率为91%~111%,定量下限(LOQ)为10μg/kg。本文还讨论了吡喹酮残留物的提取条件、流动相对吡喹酮ESI离子化的影响,并借助准MS/MS/MS技术探讨了吡喹酮主要质谱碎片的产生机理。     

高效液相色谱法测定水产品中残留的吡喹酮

建立了一种灵敏度高、操作简单的定量分析水产品中残留的微量吡喹酮的高效液相色谱方法。样品经乙酸乙酯提取、极性硅胶柱净化后进行高效液相色谱分析,以乙腈-水(体积比为50∶50)为流动相,流速为0.9 mL/min,ZORBAX C18色谱柱分离,紫外检测波长为214 nm。在此条件下吡喹酮在0.02～20 mg/L范围内呈线性关系,相关系数为0.99998;吡喹酮的加标回收率在85%以上,检出限为10 μg/kg。     

CdX(X=Se,Te,Te/ZnS)量子点脂质体的制备及毒性比较

在水相中以巯基乙酸(mercaptoacetic acid, MA)为稳定剂合成了CdSe、CdTe、CdTe/ZnS量子点及谷胱甘肽(glutathione, GSH)为稳定剂合成了CdTe量子点,然后通过卵磷脂和胆固醇修饰制得相应的量子点脂质体。溶血实验证实GSH修饰量子点的溶血率低于MA修饰的量子点45%;脂质体修饰后,量子点的溶血率＜5%,达到生物医用材料要求。不同表面修饰的量子点对小鼠毒性存在明显差异,荧光显微镜观察组织切片证实量子点在小鼠体内主要分布在肺、肾、胸腺等组织中,而脂质体量子点在脑组     

高效液相色谱法测定吡喹酮在脑囊虫病人脑脊液中的浓度及药代动力学参数

作者建立了高效正相色谱法,测定脑囊虫病人脑脊液和血浆吡喹酮浓度。色谱柱为Partisil Si(Whatman);用环己烷:乙酸乙酯:四氢呋喃:甲醇=52.3:38.0:4.7:5.0流动相洗脱,流速为0.8ml/min;用RF-530型荧光检测器检测吡喹酮峰,λ_(ex) 268nm,λ_(em)285nm。检测限为100ng。人脑脊液吡喹酮浓度,至今未报道过。文中还列出了脑脊液和血浆吡喹酮药代动力学参数。     

高效液相色谱法测定吡喹酮在脑囊虫病人脑脊液中的浓度及药代动力学参数

 〕作者建立了高效正相色谱法，测定脑囊虫病人脑脊液和血浆吡喹酮浓度。色谱柱为PartisilSi(Whatman)；用环己烷：乙酸乙酯：四氢呋喃：甲醇=52.3:38.0:4.7:5.0流动相洗脱，流速为0.8ml/min；用RP-530型荧光检测器检测吡喹酮峰，薳λ260nm.em285nm。检测限为100ng。人脑脊液吡喹酮浓度，至今未报道过。文中还列出了脑脊液和血浆吡喹酮药代动力学参数。     

纳络酮对氯化铝导致的小鼠学习记忆障碍及血中锌铜锰含量变化的影响

通过口服氯化铝建立小鼠学习记忆障碍模型,在此模型的基础上用跳台法观察了纳络酮对铝中毒小鼠学习记忆障碍的改善作用,并采用火焰原子吸收分光光度法测定了小鼠血中锌(Zn)、铜(Cu)、锰(Mn)的含量.结果显示,氯化铝可导致小鼠学习记忆障碍,且降低血中Zn、Cu含量(P＜0.05),而纳络酮有改善铝中毒小鼠学习记忆障碍的作用,同时也增加了血中Zn、Cu含量.     

纳络酮对氯化铝导致的小鼠学习记忆障碍及血中锌铜锰含量变？…

通过口服氯化建立小鼠学习记忆障碍模型,在此模型的基础上用跳台法观察了纳络酮对铝中毒小鼠学习记忆障碍的改善作用,并采用火焰原子吸收分光光度法测定了小鼠血中锌,铜,锰的含量。结果显示,氯化铝可导致小习学生记忆障碍,且降低血中Ｚｎ、Ｃｕ含量（Ｐ〈０．０５）,而纳络酮有改善铝中毒小鼠学习记忆障碍的作用,同时也增加了血中Ｚｎ、Ｃｕ含量。     

紫外分光光度法测定海星皂甙的含量

海星皂甙与浓硫酸反应生成α,β 不饱和酮,在277nm处产生特征吸收峰,据此建立了紫外分光光度法测定海星皂甙含量的分析方法。该法测定皂甙的百分吸光系数E1%为149mL·g-1·cm-1,线性范围10～50μg/mL,检出限为0.37μg/mL。方法1cm,λmax用于不同种类海星组织中的皂甙含量测定,简单快速,稳定性好,精密度高,结果令人满意。     

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.