固相萃取-高效液相色谱法测定化妆品中的鞣花酸含量

建立了固相萃取-高效液相色谱法测定化妆品中鞣花酸的含量。样品用甲醇-水(1+1)溶液提取,超声提取10min,以10 000r·min-1转速离心5min,移取5.00mL上清液,经MAX固相萃取柱处理,用甲酸-甲醇(5+95)溶液洗脱。MG C18柱(250mm×4.6mm,5μm)为固定相,以0.2%(体积分数)磷酸-乙腈(18+82)溶液为流动相进行洗脱,检测波长为254nm。线性范围为0.5~100mg·L-1,测定下限(10S/N)为20mg·kg-1,应用该方法对化妆品中鞣花酸的含量进行检测,加标回收率在83.5%~100%之间。     

气相色谱法测定建筑用粘接剂中6种磷酸酯的含量

提出了气相色谱法测定建筑用粘接剂中6种磷酸酯含量的方法。样品用甲醇超声提取15min。用HP-50+毛细管色谱柱(30m×0.53mm,1μm)分离,火焰光度检测器检测。6种磷酸酯在一定的质量浓度范围内与其峰面积均呈线性关系,检出限(3S/N)在0.8~1.5mg·kg-1之间,测定下限(10S/N)在2.5~5.0mg·kg-1之间。以空白建筑用粘接剂样品为基体进行加标回收试验,所得回收率在83.2%~97.0%之间,相对标准偏差(n=6)在5.0%以内。     

高效液相色谱法测定生活用纸中13种丙烯酸酯类化合物的残留量

应用高效液相色谱法测定生活用纸中13种丙烯酸酯类化合物的残留量。样品以甲醇-异丙醇(1+2)混合液超声提取15min,以Zorbax Extend-C18色谱柱(250mm×4.6mm,5μm)为固定相,用乙腈和水以不同比例混合的溶液为流动相进行梯度洗脱,在检测波长210nm处进行测定。13种丙烯酸酯类化合物的质量浓度均在0.1~2.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.14~0.57mg·kg-1之间。以空白样品为基体进行加标回收试验,所得回收率在80.2%~104%之间,测定值的相对标准偏差(n=6)在3.3%~7.4%之间。     

高效液相色谱法测定化妆品中4种硝基咪唑类药物

采用高效液相色谱法测定化妆品中的甲硝唑、替硝唑、奥硝唑和塞克硝唑。样品经甲醇和0.1mol·L-1盐酸溶液以体积比1比1组成的混合溶液超声提取15min后,以C18色谱柱为分离柱,以甲醇-乙腈-水(7+1+2)混合液为流动相,在检测波长315nm处进行测定。4种硝基咪唑类药物在一定的质量浓度范围内与峰面积呈线性关系,方法检出限(3S/N)和测定下限(10S/N)分别低于10 mg·kg-1和30 mg·kg-1。以空白样品为基体进行加标回收试验,测得回收率在93.8%~104%之间,相对标准偏差(n=6)在0.2%~4.1%之间。     

免疫亲和层析净化-高效液相色谱法测定大米中桔霉素

大米样品经甲-醇10 mmol.L-1磷酸溶液(70+30)提取,提取液稀释过滤后经CitriTestTM免疫亲和柱层析净化后用高效液相色谱法测定其桔霉素的含量。以Kromasil 100-10 C18色谱柱(250 mm×4.6 mm,5μm)为分离柱,甲酸(1+99)溶液与乙腈以体积比1比1混合的溶液作流动相,采用荧光检测,激发波长为350 nm,发射波长为500 nm。必要时采用液相色谱-串联质谱法对结果作验证。桔霉素的质量浓度在5.0~500.0μg.L-1范围内与其峰面积呈线性关系,测定下限(10S/N)为10.0μg.kg-1。方法的回收率为73%~76%,相对标准偏差(n=8)为7.5%~11.8%。     

衍生液提取-高效液相色谱法快速测定香菇中的游离甲醛

以2,4-二硝基苯肼乙腈溶液-pH 5磷酸盐缓冲液(体积比为1:1)为提取溶液,提取香菇中游离的甲醛,采用高效液相色谱法测定。结果表明,乙腈-pH 5磷酸盐缓冲液(体积比为1:1)能够有效地抑制香菇中酶反应释放甲醛,达到提取香菇中游离甲醛的目的。在提取液中加入衍生化试剂2,4-二硝基苯肼,将甲醛的提取和衍生化反应相结合,此衍生液提取方法有效地提高了检测效率。鲜香菇样品中分别添加5.0、10.0、20.0 mg/kg的甲醛,平均回收率分别为89.2%、91.7%和90.4%,相对标准偏差(n=6)＜5.0%。方法的定量限（S/N＞10）为5.0 mg/kg。该方法适用于香菇中游离甲醛的检测,且快速简便、重现性好,是确定香菇中甲醛天然本底值的有效方法。     

高效液相色谱法测定化妆品中5种性激素

应用高效液相色谱法测定化妆品中5种性激素的含量。化妆品样品以甲醇提取,采用Kromasil 100-5C18色谱柱为分离柱,以乙腈-水(65+35)溶液为流动相,在检测波长242nm和290nm处进行测定。5种性激素的质量浓度均在0.100~10.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.552~1.01 mg·kg-1之间,测定下限(10S/N)在1.10~5.04mg·kg-1之间。加标回收率在96.2%~110%之间,测定值的相对标准偏差(n=9)在均小于10%。     

在线衍生-高效液相色谱法测定化妆品中的游离甲醛

采用自动在线衍生-高效液相色谱法测定化妆品中游离甲醛的含量。样品经乙腈涡旋提取,以2,4-二硝基苯肼的乙腈-乙酸溶液为衍生液,在线衍生2min后,衍生物在Agilent C_(18)色谱柱上分离,以乙腈(65+35)溶液为流动相进行洗脱,用二极管阵列检测器测定,检测波长为355nm。甲醛线性范围为1.0~20.0mg·L~(-1),测定下限(10S/N)为50mg·kg~(-1)。加标回收率在83.0%~98.4%之间,测定值的相对标准偏差(n=6)在3.4%~7.8%之间。     

高效液相色谱法测定发泡聚苯乙烯材料中六溴环十二烷含量

采用高效液相色谱法测定发泡聚苯乙烯材料中六溴环十二烷的含量。发泡聚苯乙烯材料样品用乙腈提取,以GL Sciences Inc Inertsil ODS-SP色谱柱(250mm×4.6mm,5μm)为分离柱,以乙腈-水(85+15)溶液为流动相,在检测波长254nm处进行测定。六溴环十二烷在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在140~200mg·kg-1之间。以空白样品为基体进行加标回收试验,所得回收率在88.6%~103%之间,测定值的相对标准偏差(n=7)在1.2%~6.5%之间。     

高效液相色谱法测定指甲油中甲醛、乙醛和丙酮

采用高效液相色谱法测定指甲油中甲醛、乙醛和丙酮的含量。样品用乙腈和水提取,2,4-二硝基苯肼为衍生剂,采用Kromasil-C18色谱柱为分离柱,以乙腈-水(65+35)溶液为流动相,在检测波长364nm处进行测定。甲醛、乙醛和丙酮的质量浓度均在0.01~20.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.001 5~0.003 5mg·L-1之间。加标回收率在88.6%~110%之间,相对标准偏差(n=6)在1.2%~9.7%之间。     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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 novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.