反相高效液相色谱法检测辣椒酱中的苏丹红染料

采用反相高效液相色谱法检测辣椒酱中的苏丹红染料．辣椒酱经正己烷-丙酮溶剂提取,用氧化铝层析柱进行固相萃取净化,用紫外可见光检测器检测,选择ZorbaxSB—C18色谱柱检测苏丹红Ⅰ、苏丹红Ⅱ、苏丹红Ⅲ和苏丹红Ⅳ,加标回收率为91％～95％,测定结果的相对标准偏差为0．89％～1．79％。     

高效毛细管电泳法测定姜黄中姜黄素类化合物

用高效毛细管电泳法测定姜黄中姜黄素类化合物的含量;姜黄素类化合物毛细管电泳谱图的峰面积和浓度具有良好的线性关系;方法的精密度RSD为1.12％～2.47％(n=5),平均回收率为97．5％～98．1％。     

凝胶净化/超高效液相色谱电喷雾质谱法检测调味油中11种禁用偶氮染料及罗丹明B

建立了凝胶渗透色谱(GPC)净化/超高效液相色谱-电喷雾串联四极杆质谱(UPLC-MS/MS)同时检测调味油中11种脂溶性偶氮类工业染料(苏丹红Ⅰ、苏丹红Ⅱ、苏丹红Ⅲ、苏丹红Ⅳ、苏丹红7B、苏丹红G、苏丹黄、苏丹橙G、苏丹蓝Ⅱ、甲苯胺红、对位红)和罗丹明B的分析方法。样品经乙酸乙酯-环己烷(1∶1)提取,采用凝胶渗透色谱(GPC)去除大分子油脂、天然色素等干扰物质;以乙腈-0.1%甲酸为流动相,目标化合物在梯度洗脱条件下经C18柱分离后采用多离子反应监测(MRM)正离子模式进行检测。结果表明:调味油中12种工业染料的线性范围为1～50μg/L,定量下限(LOQ)为0.2～2.5μg/kg,在5、20、40μg/L 3个加标水平下的回收率为54%～125%,相对标准偏差为2.5%～17.2%。随机抽取市售35份样品进行检测,其中两份样品检出罗丹明B。该方法操作简便、灵敏度高,实现了11种禁用偶氮染料和罗丹明B的同时提取和净化,适合于调味油中非法添加脂溶性偶氮工业染料和罗丹明B的筛查与确证。     

凝胶净化/高效液相色谱-串联质谱法检测辣椒制品及肉制品中多种脂溶性着色剂

建立了凝胶渗透色谱净化/高效液相色谱-串联质谱测定辣椒制品和肉制品中苏丹橙G、甲基黄、对位红,柑桔红2号,苏丹红G,苏丹Ⅰ,苏丹Ⅱ,苏丹Ⅲ,苏丹红7B,苏丹红B和苏丹Ⅳ的分析方法。样品经乙酸乙酯或乙腈-乙酸乙酯溶液提取后采用凝胶渗透色谱净化,通过ACQUITY HPLC BEH C18色谱柱以体积分数0.1%甲酸-体积分数0.1%甲酸甲醇溶液作流动相梯度洗脱分离,采用多反应监测模式进行检测。目标分析物使用同位素内标苏丹Ⅰ-D5和苏丹Ⅳ-D6定量,11种待测物质量浓度在10~500 ng/mL范围呈良好线性关系,相关系数大于0.99,方法的定量下限均达到5μg/kg。空白样品在5,10,20μg/kg 3个加标水平下的平均回收率为80.7%~100.9%,相对标准偏差(n=10)均小于10%。     

GPC—HPLC—RP法检测熏烧烤肉制品中的苯并（a）芘

采用MPS全自动样品净化系统中的GPC凝胶渗透色谱净化熏烧烤肉制品中的苯并（a）芘（BaP）,并用高效液相色谱荧光法（HPLC—RP）测定BaP的含量。GPC条件：GPC凝胶渗透色谱柱,以环己烷-乙酸乙酯（体积比50：50）为流动相,流速4．7mL／min,收集时间为15—21min。HPLC条件：Diamonsil C18色谱柱（250mm×4．6mm,5μm）;流动相：乙腈-水（体积比88：12）,流速为1．0mL／min;柱温：30℃;进样量：10μL;激发波长：384nm;发射波长：406nm。该方法线性关系良好,加标回收率为82．4％～91.3％,相对标准偏差小于5％,检出限为0．15μg／kg。方法简化了手工操作,有效地去除了熏烧烤肉制品中的色素及脂肪干扰,可应用于熏烧烤肉制品中BaP的测定。     

大孔树脂吸附和分离密蒙花黄色素

本文研究了用大孔树脂吸附和分离密蒙花黄色素，比较了四种树脂对密蒙花黄色素的吸附。选用经x—5作吸附剂，洗脱剂用60％乙醇，产品质量较传统法好，提取率达8％，x－5树脂非常稳定，使用15次后其吸附率仅降低4．95％。     

高效液相色谱化学发光检测法测定食品中苏丹红Ⅰ

基于碱性条件下,苏丹红Ⅰ对鲁米诺-KIO4发光体系的增敏作用,建立了高效液相色谱化学发光测定苏丹红Ⅰ的新方法。方法采用Phenomenex C18色谱柱(250×4.6mm,5μm),以乙腈∶甲醇∶水=5∶4∶1(V/V/V)为流动相,在0.001～0.50μg/mL范围内,苏丹红Ⅰ浓度与发光强度呈良好的线性关系,相关系数为0.9996,检出限为5ng/kg,相对标准偏差为1.45%(c=0.01μg/mL,n=6),加标回收率为95.0%～104.0%。该法灵敏、准确,用于实际样品中苏丹红Ⅰ的测定,结果令人满意。     

凝胶渗透色谱-气相色谱质谱法测定：花生中6种除草剂农药残留

建立了凝胶渗透色谱一气相色谱质谱（GPC～GC=MS）法测定花生中6种除草剂（氟乐灵、异恶草酮、甲草胺、二甲戊乐灵、乙氧氟草醚、喹禾灵）农药残留的方法。样品经乙腈提取,氨基固相萃取柱和凝胶渗透色谱净化,在选择离子扫描（SIM）模式下进行气相色谱质谱法测定,外标法定量。6种除草剂浓度在0．02-1．00mg／L范围内与色谱峰面积呈良好的线性,线性相关系数为O．9949～0．9998,添加回收率为77．8％-101．6％,测定结果的相对标准偏差为4．4％～11．4％（月=5）,方法的检出限为0．1～1．3μg／kg。     

红腐乳及含油着色食品中苏丹红Ⅰ,Ⅱ,Ⅲ,Ⅳ的高效液相色谱法测定

建立了凝胶色谱净化、高效液相色谱检测红腐乳等含油及着色食品中苏丹红Ⅰ,Ⅱ,Ⅲ,Ⅳ的方法.用V(正己烷或乙酸乙酯):V(环己烷)=1:1提取检测食品中的苏丹红,经凝胶色谱(GPC)去除样品中分子量较大的油脂和天然色素等干扰物后,用HPLC-DAD检测.该方法在浓度0.1～20mg/L有良好的线性关系,苏丹红Ⅰ,Ⅱ,Ⅲ,Ⅳ的相关系数分别为0.9999,0.9999,0.9981,0.9900;回收率在70%～96%;检出低限为7.8μg/kg.     

GC-ECD法快速测定饮用水中卤乙酸的方法研究

通过优化卤乙酸衍生化条件、改进色谱条件,建立了一种利用短程色谱柱快速测 定饮用水中5种卤乙酸的GC-ECD方法。方法的特点是色谱程序简单、运行时间短,色谱运行时间仅为10．8min,远少于通常的运行时间。方法的检出限较低,精密度较好,除MCAA外,MBAA、DCAA、TCAA和DBAA的检出限和相对标准偏差分别小于0．46μg／L和4％（n=7）;5种卤乙酸的加标回收率在86．6％～109．3％之间,满足EPA 6251B标准方法的要求。     

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.