高效液相色谱法测定桔梗中皂苷类物质

采用高效液相色谱法测定桔梗中10种主要的皂苷类物质,桔梗样品经甲醇(60+40)溶液超声振荡提取后,过Waters Spe-Pak-C18固相萃取柱富集浓缩,以10mL·min-1的流速,用甲醇(60+40)溶液将皂苷类物质从固相萃取柱上洗脱下来.以ZORBAX Stable Bound C18(4.6 mm×100 mm,1.8μm)为快速分离柱,水和乙腈为流动相梯度洗脱,用蒸发光散射检测器检测.峰面积与10种皂苷类物质的质量浓度呈线性关系,方法检出限(3S/N)在0.3～0.8 mg·L-1之间.采用标准加入法做回收率试验,回收率在84%～106%之间,相对标准偏差(n=5)小于5%.     

超高效液相色谱-质谱联用法测定草莓中鞣花酸

建立了测定草莓中鞣花酸含量(包括游离鞣花酸和总鞣花酸)的超高效液相色谱-质谱联用(UPLCMS/MS)分析方法。草莓中游离鞣花酸在酸性条件下用甲醇提取,经C18分散固相萃取净化后可直接测定;总鞣花酸经酸性水解呈游离态再经分散固相萃取净化后进行测定。净化液经C18色谱柱分离,以甲醇和0.5%甲酸水为流动相进行梯度洗脱,电喷雾负离子(ESI-)模式电离,超高效液相色谱-质谱法(UPLC-MS/MS)测定,外标法定量。结果表明:在10~500 ng/m L浓度范围内鞣花酸的线性关系良好,相关系数为0.998 1,游离鞣花酸的定量下限为0.5 mg/kg,总鞣花酸的定量下限为5.0 mg/kg。在低、中、高3个加标浓度的回收实验中,游离鞣花酸的加标回收率为86.7%~113.6%,相对标准偏差均小于10%。该方法操作简单,灵敏度高,准确性好,适用于草莓中鞣花酸的测定。     

高效液相色谱法测定美白祛斑化妆品中氨甲环酸北大核心CSCD

采用高效液相色谱法测定美白祛斑化妆品中氨甲环酸的含量。0.500 0g样品经饱和氯化钠溶液-甲醇(1+1)混合液20mL超声提取5min,离心后,上清液于45℃水浴氮吹浓缩至近干,再加入1g·L^(-1)丹酰氯溶液500μL和100mmol·L^(-1)碳酸氢钠溶液500μL进行衍生化反应5min,冷却后,过0.22μm微孔滤膜。以Zorbax SB C18色谱柱为固定相,用乙腈和0.1%(体积分数)甲酸溶液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250nm处进行测定。氨甲环酸的质量浓度在1.0～100.0 mg·L^(-1)内与其对应的峰面积呈线性关系,检出限(3S/N)为0.3mg·kg-1。方法用于美白祛斑化妆品样品的分析,加标回收率为90.8%～98.0%,测定值的相对标准偏差(n=6)为2.0%～2.8%。     

高效液相色谱法测定化妆品中食品橙8号

应用高效液相色谱法测定化妆品中食品橙8号。以甲醇作为提取剂提取水性、膏霜乳液类化妆品中的食品橙8号,用四氢呋喃-甲醇作为提取剂提取油类、粉类、唇膏类化妆品中的食品橙8号,以甲醇-0.05%(体积分数)三氟乙酸溶液(97+3)溶液为流动相,经XDB-C18色谱柱等度洗脱,采用470 nm波长检测。方法的检出限(3S/N)为0.5 mg·kg-1,测定下限(10S/N)为1.0 mg·kg-1,回收率在96.4%~105%之间,相对标准偏差(n=6)在0.49%~4.8%之间。     

高效液相色谱-串联质谱法测定化妆品中壬基苯酚

提出了高效液相色谱-串联质谱法测定化妆品中壬基苯酚含量的方法。化妆品试液用甲醇-二氯甲烷（8+2）混合溶液超声提取30 min[唇膏类试样用无水乙醇-二氯甲烷（8+2）混合溶液],离心分离取上清液过Oasis HLB固相萃取柱净化。从SPE净化柱所得淋出液,以WatersXBridge C₁₈色谱柱（2.1 mm×150 mm,3.5μm）为固定相分离,以不同体积比的甲醇和氨水（0.1+99.9）溶液为流动相梯度洗脱,串联质谱进行测定。采用电喷雾负离子模式多反应监测,内标法定量。壬基苯酚的线性范围为10～500μg·L^-1,测定下限（10S/N）为0.2 mg·kg。方法用于分析4种类型化妆品样品,回收率在83.1%～103.0%之间,相对标准偏差（n=6）在2.75%～9.24%之间。     

水龙骨中没食子酸与鞣花酸的含量测定

以Spursil C18色谱柱(250 mm×4.6 mm, 5μm)、甲醇-0.1%磷酸水溶液为流动相进行梯度洗脱、流速1.0 mL/min、检测波长255 nm和柱温30℃为色谱条件，建立了HPLC法测定水龙骨中没食子酸与鞣花酸含量的方法。结果表明：没食子酸在浓度为0.5～5.0 mg·L^-1的范围内(r=0.999 9),鞣花酸在质量浓度为6.944×10^-3～69.44×10^-3μg的范围内(r=0.999 8)与峰面积呈良好的线性关系；没食子酸和鞣花酸平均加样回收率分别为104.21%和101.52%,RSD值分别为4.51%和3.83%;按外标法测得水龙骨中没食子酸含量(n=6)为26.83μg·g^-1,鞣花酸含量(n=6)为62.18μg·g^-1。该测定方法易操作、稳定性及重复性好，为水龙骨药材质量研究提供科学依据。     

固相萃取-高效液相色谱法测定化妆品中乐杀螨和克螨特

建立了固相萃取-高效液相色谱法检测化妆品中乐杀螨和克螨特的方法。样品用正己烷提取,水浴中超声提取15min,8 000r·min-1离心分离3min。取上清液2mL加入活化后的Florosil固相萃取小柱,用3mL 5%丙酮-正己烷溶液洗脱,收集洗脱液于常温氮吹至干,用1mL乙腈溶解。试样经SB C18柱(250×4.6mm,5μm)分离,流动相为水∶乙腈(26∶74,V/V),检测波长224nm。该方法乐杀螨检出限和定量限分别为3.5mg·kg-1和10mg·kg-1,克螨特检出限和定量限分别为8.0mg·kg-1和25mg·kg-1,乐杀螨和克螨特加标回收率分别为82.6%~107.0%和80.4%~105.9%。该方法简便、准确,适用于化妆品中乐杀螨和克螨特的检测。     

高效液相色谱法测定椰油醇酰胺类表面活性剂中 N-亚硝基二乙醇胺的含量

采用高效液相色谱-紫外检测器测定椰油酸单乙醇酰胺和椰油酸二乙醇酰胺中的N-亚硝基二乙醇胺的含量。称取样品0.100 0g,用甲醇(8+2)溶液溶解并定容至10.0 mL,超声10min,经0.45μm微孔滤膜过滤后,滤液供高效液相色谱分析。以Diamonsil C_(18)硅胶键合相色谱柱(4.6mm×250mm,5μm)为固定相,以不同比例的甲醇-水体系为流动相进行梯度洗脱,采用紫外检测器在波长233nm处进行测定。N-亚硝基二乙醇胺的质量浓度在0.05～25.00mg·L~(-1)内与其峰面积呈线性关系,检出限(3S/N)和测定下限(10S/N)分别为15,48μg·L~(-1)。加标回收率在94.5%～98.5%之间,测定值的相对标准偏差(n=5)在3.8%～5.9%之间。     

双波长UPLC同时测定桃金娘根中没食子酸和鞣花酸

建立了超高效液相色谱(UPLC)结合二极管阵列检测器(PDA)同时测定桃金娘根中没食子酸和鞣花酸的方法。样品经过甲醇超声提取,过滤,蒸干甲醇,残渣用二甲基亚砜定容。采用Waters BEH C18色谱柱(2.1×100 mm1.7μm),以乙腈-0.2%H2PO4溶液为流动相进行梯度洗脱,流速0.25 m L/min,检测波长为271 nm和253 nm。没食子酸在0.686~68.600μg/m L,鞣花酸在0.504~50.373μg/m L浓度范围内呈良好线性关系,相关系数分别为0.9999,0.9999;样品加标平均回收率分别为97.2%~99.0%、96.2%~98.9%;没食子酸和鞣花酸峰面积的RSD分别为1.1%和1.9%,迁移时间RSD为0.9%和1.3%;检出限分别为0.45和0.23 ng/m L。     

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%。     

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.