固相萃取-HPLC法测定蜂蜜中残留的10种磺胺类药物

研究了用固相萃取-高效液相色谱法同时测定蜂蜜中10种磺胺类药物残留量的方法。样品经三氯甲烷溶液提取,过Oasis HLB C18固相萃取柱净化,用乙腈洗脱10种磺胺,反相高效液相色谱-紫外检测器测定。检测波长为270nm,柱温45℃．流动相：磷酸水溶液-乙腈梯度洗脱．该方法前处理简单,梯度洗脱分离效果和重现性好,在0．010～1．0mg／kg添加水平,10种组分的回收率在86．5％～100．8％之间,室内相对标准偏差在3．5％～8．1％之间,线性范围为0．010～10μg／mL,检出限为0．005mg／kg。该方法快速、灵敏、专属,可用于食品中磺胺类药物残留量的常规检测。     

高效液相色谱法测定盐酸噻吩诺啡有关物质的方法研究

建立盐酸噻吩诺啡药物有关物质检查的液相色谱方法。采用ZORBAX—C18色谱柱,流动相为甲醇-乙腈-（0．002mol／L KH2PO4—0．3％三乙胺,pH3）,检测波长为220nm。该方法能较好地分离药物与有关物质,样品在测定浓度范围内线性关系良好,药物纯度为99．0％以上。对药物中的未知杂质用质谱法鉴定,确认杂质来源。方法可用于盐酸噻吩诺啡药物的有关物质检测。     

高效液相色谱法测定动物源食品中磺胺类药物残留量

试样中残留磺胺药物用乙腈提取并经正己烷萃取和通过碱性氧化铝层析柱进行净化。所得乙腈-水（30＋70）洗脱液用于高效液相色谱法测定。采用C18色谱柱（250mm×4．6mm）作固定相,以乙腈（A）及乙腈＋乙酸＋水（20＋1＋79）的混合液（B）按不同比例混合液作流动相进行梯度淋洗使5种磺胺药物分离,最后在270nm波长处作紫外检测,所测定的磺胺药物的质量浓度与其峰面积之间在0．05～1.00mg·L^-1范围内呈线性关系。方法的测定下限（S／N=10）为0．04mg·kg^-1,以猪肉样品为基体加入3种药物的标准溶液进行回收试验,测得回收率在73．65％～93．45％之间。     

多功能柱净化-高效液相色谱法同时检测小麦中雪腐镰刀菌烯醇和脱氧雪腐镰刀菌烯醇

建立了小麦中雪腐镰刀菌烯醇（NIV）和脱氧雪腐镰刀菌烯醇（DON）的高效液相色谱同时检测方法。样品采用乙腈-水（体积比85：15）混合溶剂进行提取．通过多功能净化柱（MFC）进行一次性净化,以C18柱为分离柱,水-乙腈-甲醇（体积比90：5：5）混合溶剂为流动相进行高效液相色谱分离和检测。在小麦样品中,本方法在0．2～5μg／g添加范围内的凹收率为87％～99％;相对标准偏差为1．5％～8．3％;DON和NIV的检出限分别为0．12和0、16μg／g（5／N=3）。     

固相萃取-梯度洗脱高效液相色谱法同时检测饲料中十三种磺胺类药物

建立了一种同时检测饲料中十三种磺胺类药物含量的方法,样品用磷酸盐缓冲液提取,HLB固相萃取小柱净化,梯度洗脱-HPLC分析,方法定量下限为0．5mg／kg,在0．5～10．0mg／kg添加水平上的回收率为63．6％～118．2％,相对标准偏差4．78％～17．24％,方法简便．适用于饲料中低含量磺胺类药物检测．     

反相高效液相色谱法用于地钱中黄酮类化合物的分离与测定

采用反相高效液相色谱,在RP—C18柱上以乙酸-甲醇-乙腈-磷酸-水为多元流动相,等度洗脱,在30min内对地钱的黄酮提取物进行分离与测定,检测波长350nm,流速0．60mL／min,采用校准曲线法对实际样品中的芹菜素、槲皮素和木犀草素进行定量分析。结果表明：平均加标回收率96．79％～101．13％．相对标准偏差0．66％～1．52％．     

高效液相色谱法测定动物组织中8种磺胺类药物残留量

提出了一种快速、准确地同时测定动物组织中磺胺类药物残留量的检测方法。样品中加入无水硫酸钠后,用乙腈均质、提取,在离心后的沉淀物中加入乙腈,再次提取,合并乙腈提取液。提取液用乙腈饱和正己烷溶液净化,去除脂肪和杂质,用高效液相色谱方法进行测定。通过优化色谱条件,利用紫外检测器(VWD)或二极管阵列检测器(DAD)对8种磺胺类药物残留进行同时测定,测定结果的相对标准偏差为5.1％～12.8％,平均回收率为62.7％～105．1％,检出限为10μg/kg。     

多功能柱净化-高效液相色谱法检测谷物中的玉米赤霉烯酮

建立了玉米和小麦中玉米赤霉烯酮（ZEN）的多功能柱净化-高效液相色谱检测方法。样品经乙腈-水混合溶剂（V（乙腈）：V（水）=84：16）提取,通过多功能净化柱（MFC）进行一次性净化,以Symmetry^R C18柱为分离柱,甲醇-水（V（甲醇）：V（水）=68：32）为流动相进行高效液相色谱分离和检测。玉米赤霉烯酮的质量浓度在0．01～4．0μg／mL范围内呈良好线性,相关系数为0．9996。检出限为0．04μg／g,在0、04—5．0mg／kg添加范围内的回收率为87．5％～98．6％,相对标准偏差为1．5％～8．3％。     

生鲜牛乳中农药多残留分析方法研究

本文报道生鲜牛乳中不同类型农药的多残留同时快速检测方法。样品经乙腈、丙酮(1：1,V／V)混合溶剂提取,离心,C18固相萃取柱纯化、富集,采用毛细管气相色谱法,电子捕获检测器检测,进行定性、定量检测有机氯、有机磷和拟除虫菊酯等14种农药的残留量。本法的加标回收率为78．5％～104．6％(敌敌畏为63．2％);检出限为0．5～14．0μg／L;线性相关系数,r^2≥0．9922。     

大豆中6种磺酰脲类除草剂残留量的高效液相色谱-质谱法测定

建立了LC—MS选择离子监测(SIM)同时检测大豆中6种磺酰脲类除草剂残留量的方法。样品经乙腈提取，正己烷液-液分配，Florisil柱净化，然后采用HPIE—ESI( )-MS测定。6种磺酰脲类除草剂在25～1000μg／L范围内线性良好，相关系数为0．9996～0．99977在0．02～1．0mg／kg范围内，平均加标回收率在72％～99％之间，相对标准偏差为0．9％～7．7％。方法的检出限低于10μg／kg。     

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.