气相色谱法测定木香中去氢木香内酯的含量

建立气相色谱法测定木香中去氢木香内酯的含量。选择HP–5毛细管色谱柱(30m×320μm,0.25μm),用FID检测器检测,进样口温度为280℃,柱温箱初始温度为150℃,保持3 min,以12℃/min升温至280℃,载气为氮气,流量为3.0 mL/min。去氢木香内酯的质量浓度在1.996～199.6μg/mL范围内与色谱峰面积呈良好的线性,线性相关系数r=0.999 5,加标回收率为98.26%～100.87%,6次平行测定结果的相对标准偏差为0.69%(n=6)。该方法简单,重现性好,可用于木香中去氢木香内酯含量的测定。     

保健酒中酞酸酯污染物的气相色谱-三重四极杆质谱法测定

建立了气相色谱—三重四极杆质谱(GC-MS/MS)联用法检测保健酒中的16种酞酸酯的方法.对保健酒中酞酸酯的前处理方法进行了考察和优化,确立了提取方式为沸水浴加热去除乙醇、提取溶剂为正己烷.采用时间选择反应扫描模式(T-SRM)定量.色谱柱为TG-5MS石英毛细管柱(30 m×0.25 mm×0.25μm),程序升温(初始柱温为60℃,保持1 min,以20℃/min升至220℃,保持1 min;以5℃/min升至280℃,保持4 min),不分流.结果表明16种酞酸酯在相应范围内线性关性良好(R~2均高于0.995),平均回收率在84.0%~112.8%,RSD均低于7%(n=6).采用方法对6批保健酒中酞酸酯进行测定,结果表明方法具有灵敏、简单快速、结果准确可靠等优点,GC-MS/MS联用法可满足保健酒中酞酸酯的定性分析和含量测定.     

气相色谱反吹法分析二氨基二苯甲烷产品中的微量苯胺

利用气相色谱反吹技术,针对二氨基二苯甲烷产品的高沸点、多组分、粘度大的特点,采用氢火焰检测器;安装六通阀、锥形阀、电磁阀,实现气路转换、气路平衡、气路反吹功能;筛选多种色谱柱,调节进样口温度、柱箱温度、反吹时间等:选用SE-30填充柱(3 m×3 mm),进样口温度280℃,检测器温度280℃,柱箱温度100℃(1 min)-40℃/min-120℃(0.1 min)-60℃/min-260℃(4 min),在2.8 min开启反吹,反吹时间3.6 min。苯胺含量在0.096~3.110 mg/m L之间呈良好线性关系,相关系数为0.9916,检出限为13.04μg/m L,样品加标回收率在93.5%~106.3%之间,RSD小于4.4%.实验验证反吹气路和分析方法的可行性,方法适用于工业分析。     

气相色谱法同时测定艾叶中4种挥发性成分

建立同时测定艾叶中桉油精、樟脑、薄荷脑、龙脑4种挥发性成分含量的分析方法。样品采用水蒸气蒸馏法提取。色谱柱采用DB–WAX毛细管柱(30 m×0.32 mm,0.25μm);载气为氮气(99.99%),分流比为10∶1;进样口温度为240℃;升温程序:柱温起始温度70℃,保持1 min,然后以5℃/min的速率升温至150℃,保持2 min,再以10℃/min的速率升温至200℃,保持6 min;氢火焰离子化检测器(FID)温度为240℃。桉油精的质量浓度在0.05~0.8 mg/m L范围内与色谱峰面积呈良好的线性,相关系数r0.999;樟脑、薄荷脑、龙脑的质量浓度在0.01~0.2mg/m L范围内与色谱峰面积线性关系良好,相关系数r0.999;方法回收率为92.00%~98.40%,测定结果的相对标准偏差为1.58%~2.44%(n=6)。桉油精、樟脑、薄荷脑、龙脑检出限分别为0.66,0.76,0.81,0.83 mg/kg。该方法操作简单,准确度与灵敏度高,适合同时测定艾叶中桉油精、樟脑、薄荷脑、龙脑4个挥发性成分含量。     

毛细管柱气相色谱法测定花生油中脂肪酸甲酯

采用毛细管柱气相色谱法测定油脂中7种脂肪酸甲酯的含量,选用HP-INNOWAX毛细管色谱柱(1 μm,30 m×0.53 mm),氢火焰离子化(FID)检测器,进样口温度250℃,柱温220℃,检测器温度280℃,载气流量128 mL·min-1的色谱条件,以保留时间定性,面积归一法定量.按所提的方法测定了花生油标样中7种脂肪酸甲酯的含量,测得结果与标准值相符合,测定值的相对标准偏差在0.1%～5.6%之间.     

气相色谱法测定茄尼醇中有机溶剂残留量

建立了测定茄尼醇中甲醇、正已烷、乙腈残留量的气相色谱法.样品和对照品均以异丙醇为溶剂,四氢呋喃为内标物. 色谱柱HP-5MS石英毛细管柱(5%苯基硅氧烷-95%甲基聚硅氧烷,30 m×0.25 mm×0.25 μm);检测器FID. 程序升温方式:初温80 ℃,保持5 min,以8 ℃/min升温至120 ℃,保持10 min;汽化室温度200 ℃;进样口温度250 ℃;高纯N2气为载气,流速2.0 mL/min;进样量2 μL.     

HPLC法同时测定油橄榄叶中的5种多酚类化合物含量

建立了HPLC法同时测定油橄榄叶抗糖尿病有效部位中的5种多酚类化合物含量。优选的色谱条件为:色谱柱:Sinochrom ODS-BP柱(250×4.6 mm,5μm);DAD检测器;检测波长:230 nm;流速:1.0 mL/min;柱温:30℃;进样量:10μL;流动相:水(A)+甲醇(B),梯度洗脱:0~5 min,30%B;5~20 min,30%B~52%B;20~25 min,52%B~50%B。在优选的色谱条件下,5种多酚类化合物能够得到较好的分离。日内RSD为1.4%~2.6%,日间RSD为0.8%~2.8%,回收率为97.1%~113.2%。方法可用于测定油橄榄叶及其抗糖尿病有效部位中的5种多酚类化合物的含量。     

气相色谱法测定聚异丁烯丁二酸酐中游离酸酐

建立气相色谱法测定聚异丁烯丁二酸酐中马来酸酐含量的方法。样品用有机溶剂萃取后进色谱柱分离。色谱柱采用HP-FFAP极性毛细管柱（30 m×0.32 mm,0.25μm）,载气为高纯氮气,分流比为1∶40,进样口温度为240℃,采用程序升温方式,初始温度为50℃,以10℃/min的速率升温至230℃,保持10 min,氢火焰离子化检测器温度为260℃。马来酸酐的质量分数在0～0.40%范围内与色谱峰面积线性良好,相关系数大于0.999。样品加标回收率为96.72%～99.35%,测定结果的相对标准偏差为1.172%～1.949%(n=6)。该方法操作简便、快捷、准确度高,可以满足实际生产需求。     

气相色谱法测定香水中乙醇含量的研究

本文建立了香水中乙醇含量的气相色谱检测方法.选用强极性的Agilent DB-WAXETR毛细管色谱柱(60 m×0.32 mm×0.5 μm),进样口温度180℃,分流比100∶1,进样量1μL,载气为高纯氮气,升温程序:90℃保持14 min,以30℃/min升至180℃,保持3 min,FID温度200℃.结果表明,乙醇含量在2％～20％的范围内有良好的线性(r2=0.99986),回收率为99.33％～101.00％.建立的方法简便、快速、准确,可用于检测香水中的乙醇含量.     

高效液相色谱法同时测定丹参提取物中4种成分的含量

建立反相高效液相色谱法同时测定丹参醇提物和超临界提取物中原儿茶醛、丹酚酸B、隐丹参酮和丹参酮ⅡA含量的方法.采用RP-HPLC梯度洗脱的方法进行测定,色谱条件为:Agilent C18柱(5 μm,4.6×250 mm);以1%醋酸乙腈-1%醋酸水为流动相进行梯度洗脱;检测波长:0～25 min (280 nm),25～60 min (270 nm);流速0.5 mL/min;柱温:35 ℃.测定了丹参醇提取及超临界提取物中以上4种成分的含量;4种成分线性关系均良好(r>0.9995),平均加样回收率均大于95.0%,RSD均小于3.0%.该方法一次进样,可以同时测定丹参中水溶性成分原儿茶醛和丹酚酸B、脂溶性成分隐丹参酮和丹参酮ⅡA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%.     

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.