反相高效液相色谱法测定血浆中的辅酶Q10

建立了一种检测血浆中辅酶Q10含量的高效液相色谱法。血浆经甲醇脱脂蛋白后,以正己烷萃取,萃取液依次经硅胶柱净化、C18柱固相萃取,再进行高效液相色谱分析。色谱柱为Hypersil ODS2柱(5 μm,150 mm×4.6 mm i.d.),以异丙醇-甲醇(体积比为45∶55)溶液作流动相,辅酶Q9作内标,检测波长为275 nm。在0.1-50.0 mg/L质量浓度范围内,辅酶Q10与辅酶Q9的峰面积比与相应CoQ10的质量浓度呈良好的线性关系(r2=0.999),血浆中辅酶Q10的检测限为0.03 mg     

血浆辅酶Q10的高效液相色谱快速测定

建立了一种简单快速测定血浆辅酶Q10(CoQ10)的反相高效液相色谱方法.血浆经正丙醇萃取,上层清液直接进样分析.色谱柱为Hypersil ODS2 5μm,150 mm ×4.6 mm i.d,以异丙醇-甲醇(体积比19)作流动相,275 nm作检测波长,外标法定量.在0.05～20 mg/L范围内,峰高与质量浓度呈良好的线性关系(r=0.999 8),血浆中辅酶Q10的检出限为0.03 mg/L(S/N=3).该方法简单、快速、精密度高(RSD＜5%),适宜于血浆辅酶Q10含量的检测.     

HPLC测定青稞中的维生素E

建立了青稞中维生素E含量测定的HPLC方法,为青稞的质量评价和综合利用提供依据.采用Symmetry C18(5μm,4.6mm×250mm)色谱柱;V(甲醇):V(水)=98:2为流动相;检测波长295nm;流速1 mL/min.结果表明,青海地区的青稞维生素E总含量在0.3～0.8 mg/100 g.     

一测多评方法应用于高效液相色谱法测定防晒产品中15种防晒剂的含量

选用CAPCELL PAK C18色谱柱为分离柱,柱温为30℃,进样体积为10.0μL,并用不同比例的(A)甲醇、(B)四氢呋喃和(C)0.008 2mol·L^-1高氯酸溶液的混合液作为流动相,按程序梯度洗脱模式对市售防晒产品中所用的15种防晒剂的标准品进行色谱分离,并在波长311nm处进行紫外检测。实样分析时,称取样品0.25g,用甲醇、四氢呋喃、水和高氯酸(体积比为250∶450∶300∶0.2)的混合液(以下简称混合溶剂)15 mL超声提取30 min,用混合溶剂定容至25.0mL,离心10min,分取上清液1.0mL,加入混合溶剂定容至10.0mL,经0.45μm滤膜过滤,取滤液按仪器工作条件进行高效液相色谱分析。结果表明:所测定的15种防晒剂在一定的质量浓度范围内与其对应的峰面积呈线性关系。选定其中的二苯酮-3为参照物,并根据其余14种化合物的质量浓度和峰面积计算了各化合物的相对校正因子和相对保留时间等参数,确定了用一测多评法(QAMS)测定防晒产品中15种防晒剂的条件。还对色谱柱的型号、色谱仪器的型号以及柱温、进样量等对相对校正因子和保留时间可能产生影响的因素进行了系统试验。证明了在选定的色谱柱型号的前提下,用QAMS方法可实现防晒产品中15种防晒剂含量的同时测定。应用QAMS方法测定了6个批次防晒产品中的防晒剂含量,所得结果与用标准曲线法计算的结果基本一致,表明QAMS方法在降低检测成本和节省检测时间方面效果显著。     

反相高效液相色谱法测定维生素K_2软胶囊中K_2(20)含量

采用外标法测定维生素K2软胶囊中维生素K2(20)的含量,建立了维生素K2(20)软胶囊含量的RP-HPLC测定方法.色谱柱为Agilent ZORBAX Eclipse XDB-C18 (150 mm×4.6 mm,5 μm),流动相为甲醇,检测波长为270 nm,流速为1.0 mL/min,线性范围为0.014～0.41 μg (r=0.9997).本法操作简便,重现性好,可用于维生素K2(20)软胶囊质量标准的建立及含量测定.     

液相色谱特征图谱用于草乌成分定量

测定不同产地草乌的液相色谱指纹图谱,构建草乌的特征图谱,对不同草乌样品进行相似性对比分析,考察不同产地草乌的生物碱总量含量差异.采用色谱柱为WelchromC18柱(250 mm×4.6 mm,5μL),流动相为甲醇–0.1％三乙胺(体积比为75:25),流量为1 mL/min,检测波长为235 nm,柱温为30℃,进样体积为20μL.对10个批次样品进行相似度分析和含量测定,确定草乌的特征图谱共有模式,标定10个特征峰,指认了新乌头碱、乌头碱、次乌头碱的特征峰.10批不同产地草乌的相似度均大于0.90,相似度较好.产地1的草乌总生物碱含量为3.4046 mg/g,在10个产地中含量最高.其它产地草乌总生物碱含量相近.     

超声辅助提取/单颗粒电感耦合等离子体质谱法测定防晒化妆品中的纳米二氧化钛

建立了超声辅助提取/单颗粒电感耦合等离子体质谱(SP-ICP-MS)测定防晒化妆品中纳米TiO_2的方法。考察了停留时间、纳米粒子数量及浓度等分析条件,确定了防晒化妆品中纳米TiO_2的最佳萃取条件以及测定方法,对比了不同萃取溶剂对防晒霜中纳米TiO_2的提取效果。结果表明,在采用0. 1%Tritonx-100(Tx-100)以及5%乙醇作为萃取剂超声辅助提取,测定停留时间为3 ms,待测样品中纳米颗粒的数量浓度低于4×10~7个/mL条件下,该法可准确测定防晒化妆品中的纳米TiO_2,对防晒化妆品中纳米TiO_2的数量浓度检出限(LOD_(conc))为1×10~4个/mL,纳米颗粒粒度检出限(LOD_(size))为35 nm。方法简单快捷、灵敏度高、准确性良好,可同时对防晒化妆品中TiO_2进行浓度测定及粒度分布表征。     

液相色谱-串联质谱法同时检测防晒化妆品中的11种紫外吸收剂

建立了防晒化妆品中11种紫外吸收剂的液相色谱-串联质谱检测方法。样品经甲醇-乙醇-水(80:10:10, v/v/v)提取,利用Eclipse XDB-C₁₈色谱柱(150 mm×4.6 mm, 5 μm)分离,以乙腈和0.1%甲酸水溶液为流动相,梯度洗脱。采用多反应监测(MRM)模式进行质谱测定,根据保留时间及质谱图上特征离子的相对丰度比进行定性,外标法定量。结果表明:该方法11种紫外吸收剂的定量限范围为200～500 mg/kg,回收率为77.17%～98.32%,相对标准偏差为2.40%～11.11%。该方法对于膏状和乳状防晒化妆品中的11种紫外吸收剂具有较好的适用性。     

高效液相色谱法测定防晒化妆品中甲酚曲唑和甲酚曲唑三硅氧烷

建立了防晒化妆品中甲酚曲唑和甲酚曲唑三硅氧烷的反相高效液相色谱分析测定方法。防晒化妆品经水-四氢呋喃-甲醇溶剂提取,过滤,用Agilent C18柱(250 mm×4.6 mm,5μm)分离,以甲酸/水(0.1%)-甲醇-四氢呋喃(2:9:9,V/V/V)为流动相等度洗脱,检测波长为340 nm,高效液相色谱-二极管阵列检测器(HPLC-DAD)进行定性定量分析。两种防晒剂质量浓度在5.0~500 mg/L范围内,线性关系良好,相关系数0.999,定量限为5.0 mg/kg,回收率达到90%~110%,相对标准偏差(n=6)小于10%。方法适用于防晒化妆品中甲酚曲唑和甲酚曲唑三硅氧烷的同时测定。     

高效液相色谱法测定微量全血中维生素A

建立了反相高效液相色谱法测定微量全血样品中维生素A的方法。取全血50μL,用100μL无水乙醇沉淀蛋白后,加入400μL×2正己烷漩涡混匀提取维生素A,高速离心分层后取正己烷层在弱氮气流下挥干,加100μL甲醇溶解后用反相色谱柱C8(150 mm×4.6 mmi.d.,5μm)分离,紫外检测波长325nm,外标法定量。色谱条件:柱温,60℃;流动相为V(甲醇)∶V(水)=92∶8;流速:0.8 mL/min。用本法同时测定了27例成人微量全血及其血清中的维生素A。标准曲线的相关系数大于0.999;相对标准偏差(RSD)小于5%。对于50μL全血,方法检出限为0.02μg/mL。加标回收率为88%~115%。成人血清与其全血中维生素A含量之比为2.907±0.160(x-±s)。方法适合于微量全血中维生素A的测定,并可以通过测定全血中维生素A含量推算血清中维生素A的含量。     

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.