胶束毛细管电泳法同时测定消栓通络片中5种有效成分

建立了胶束毛细管电泳法同时测定中药复方制剂消栓通络片中芦丁、丹参素、人参皂苷Rg1、人参皂苷Rb1、三七皂苷R1含量的分析方法。研究了缓冲体系的浓度、添加剂种类、分离电压、进样时间对组分分离的影响,以60 mmol/L SDS-30 mmol/L Tris-10 mmol/L硼酸(含15%甲醇)作运行缓冲液,检测波长214 nm,5种组分在26 min内得到基线分离。芦丁、丹参素、人参皂苷Rb1、人参皂苷Rg1、三七皂苷R1的质量浓度分别在2.5～100、2.5～200、10～300、15～400、15～400 mg/L范围内与其峰面积呈良好的线性关系,检出限分别为0.3、0.9、3.0、5.0、6.0 mg/L。样品在低、中、高3个浓度下的加标回收率为93%～108%,相对标准偏差均不大于4.5%。该方法简便、快速,可用于实际样品检测。     

流速/溶剂双梯度反相高效液相色谱法快速同时测定复方丹参片中7种有效成分

采用整体柱建立了流速/溶剂双梯度反相高效液相色谱法快速同时测定复方丹参片中三七皂苷R1,人参皂苷Rg1,Re,Rb1,Rd,Rb2及丹参酮ⅡA 7种有效成分。通过对溶剂和流速双梯度体系的逐步优化,并应用色谱模拟软件Dry Lab,得到分离7种成分的最佳色谱条件。采用色谱柱Merck Chromolith Performance RP-18e(100 mm×4.6 mm),以乙腈-水为流动相体系,流速/溶剂双梯度洗脱,柱温30℃;片剂中的7种成分在21 min内达到基线分离;Rg1在60.60~242.40 mg/L(r=0.999 0)、丹参酮ⅡA在16.52~66.08 mg/L(r=0.999 9),其余皂苷在30.70~142.66 mg/L(r≥0.999 4)范围内具有良好的线性关系;定量下限(S/N=10)为21~124μg/kg,回收率为96.7%~100.1%。该方法能在短时间内同时分离不同极性的化合物,提高被测物的柱效,减少半峰宽和拖尾,可应用于复方丹参片中7种成分的含量分析。     

毛细管电泳-电化学检测法测定淮山中薯蓣皂苷和腺苷含量

建立了毛细管电泳-电化学检测(CE-ED)法测定淮山中薯蓣皂苷和腺苷的含量。考察了检测电位、运行缓冲液浓度和pH、分离电压及进样时间等的影响。在优化的实验条件下,对0.1mg/L薯蓣皂苷、腺苷在9min内实现了分离,其线性范围分别为0.1~1 000μg/L和0.1~1 200μg/L;检出限分别为0.04μg/L和0.03μg/L,峰电流的相对标准偏差(RSD,n=6)分别为1.7%、1.5%,迁移时间的RSD分别为0.7%、0.6%。该方法已用于淮山样品中薯蓣皂苷和腺苷的测定,样品加标回收率在98.0%~102.5%之间,RSD≤2.3%。     

毛细管电泳电致化学发光法同时测定氯丙嗪、异丙嗪及其主要代谢物

建立了同时检测氯丙嗪、异丙嗪及其主要代谢物的毛细管电泳电致化学发光新方法。最佳实验条件为: 检测电位1.20 V,钌联吡啶浓度5 mmol/L,检测池磷酸缓冲溶液40 mmol/L (pH 6.5),分离磷酸缓冲溶液18 mmol/L (pH 4.8),进样电压11 kV,进样时间8 s,分离电压13.5 kV。方法的检出限(3σ)分别为氯丙嗪8.3×10~7 g/L、异丙嗪7.2×10~6 g/L、氯丙嗪亚砜1.9×10~5g/L和异丙嗪亚砜3.7×10~6g/L,各组分的电化学发光强度和迁移时间的相对标准偏差(RSD)分别不超过3%和1%。本方法具有简便、快速、灵敏、进样量少和不受共存物干扰等特点,可在不必预分离的情况下直接同时连续测定家犬尿样中的氯丙嗪、异丙嗪、氯丙嗪亚砜和异丙嗪亚砜。     

毛细管电泳-电化学发光法测定金钗石斛中石斛碱的含量

样品经乙醇萃取后,提取液采用电动进样引入毛细管中进行毛细管电泳(CE)分离,进样电压为10kV,进样时间为10s。CE运行缓冲溶液为pH 5.13的10mmol·L~(-1)磷酸盐缓冲溶液,分离电压为15kV。CE分离得到的石斛碱与电化学发光(ECL)检测池中的5 mmol·L~(-1)Ru(bpy)_3~(2+)溶液(溶剂为pH 8.10的70 mmol·L~(-1)磷酸盐缓冲溶液)反应,使得Ru(bpy)_3~(2+)的ECL强度增大,检测电位为1.17V(vs.Ag/AgCl)。石斛碱的质量浓度在1.0~100mg·L~(-1)内与ECL信号的峰面积呈线性关系,检出限(3S/N)为0.045mg·L~(-1)。方法用于测定金钗石斛中石斛碱的含量,加标回收率在92.0%~105%之间,测定值的相对标准偏差(n=5)在2.5%~5.1%之间。     

毛细管区带电泳测定食品中甲醛次硫酸氢钠

建立了毛细管区带电泳(CZE)-紫外检测法测定粉丝、挂面、冰糖及腐竹中的甲醛次硫酸氢钠含量的新方法.以Φ75!m"70 cm(有效长度:60 cm)未涂层熔融石英毛细管为分离柱,50 mmol/L磷酸钠+10 mmol/L NaOH+0.5 mmol/L十六烷基三甲基溴化铵(CTAB)+1 g/L聚乙二醇(PEG)35 000为分离缓冲溶液.详细研究了分离缓冲溶液浓度及pH、PEG 35 000浓度及样品提取溶液对甲醛次硫酸氢钠分离及定量的影响.样品粉碎后,用5mmol/L乙酸溶液提取后离心,上清液经滤膜过滤后直接进样.分离电压为-12 k V,检测波长为214 nm.检出限和定量限分别为4 mg/kg和12 mg/kg,线性范围为15~400 mg/kg,线性相关系数(r)为0.999 1,加标回收率在90.0%~95.6%之间.方法测定了从北京当地超市及农贸市场上采集的4种共计12份食品样品,未发现阳性样品.     

加压毛细管电色谱-微流蒸发光散射检测器联用系统的构建及其应用

构建微流蒸发光散射检测器(μELSD)与加压毛细管电色谱(pCEC)联用系统,测定中药提取物注射用血塞通(冻干)中三七皂苷R1、人参皂苷Rg1,Re,Rb1、Rd考察系统的实用性和稳定性。用C18毛细管色谱柱,通过对流动相体系、梯度洗脱条件、雾化载气流速、蒸发温度、施加电压等参数的优化,确定了注射用血塞通(冻干)5种成分含量测定的最佳测定参数。最佳测定参数如下,流动相A为15 mmol/L甲酸-三乙胺乙腈溶液(pH=7.0),流动相B为15 mmol/L甲酸-三乙胺溶液(pH=7.0);梯度洗脱条件:0~10 min,19%A;10~30 min,22%A;30~35 min,36%A;35~45 min,40%A。雾化载气流速2 L/min;蒸发温度120℃;施加电压+8 kV。5种成分线性范围为8.6~146.9 ng(三七皂苷R1)、6.9~189.7 ng(人参皂苷Rg1)、6.8~171.4 ng(人参皂苷Re)、9.4~156.1 ng(人参皂苷Rb1)、7.5~180.5 ng(人参皂苷Rd),5种成分回收率都在95%~105%之间。实验表明,构建的pCEC-μELSD联用系统能用于药物中有效成分的含量测定。μELSD的构建为毛细管液相色谱、毛细管电色谱和毛细管电泳分离技术提供了一种全新的检测手段。     

微流控芯片非接触电导法快速测定盐酸美金刚片中盐酸美金刚的含量

建立了微流控芯片非接触电导法快速测定盐酸美金刚片中盐酸美金刚含量的方法。探讨了缓冲溶液的种类、浓度、pH值、进样时间及分离电压等因素对分离检测的影响。优化得到缓冲体系为含2%(体积分数)二甲基亚砜(DMSO)的3.0 mmol/L三乙胺-2.0 mmol/L磷酸缓冲溶液(pH 3.3),进样时间为10 s,分离电压为2.0 kV。优化条件下,盐酸美金刚的线性范围为10～2 000μg/mL(r~2=0.999 1);检出限为7μg/mL,定量下限为10μg/mL;精密度、稳定性、重复性实验的相对标准偏差(RSD)均小于2.0%;平均加标回收率为96.5%～99.2%;盐酸美金刚的检测时间小于18 s。该方法快速简便,适用于盐酸美金刚片中盐酸美金刚含量的测定。     

阳离子选择性耗尽进样-胶束电动色谱法对可非糖浆中盐酸异丙嗪与磷酸可待因的测定

在胶束电动色谱法的基础上,联用阳离子选择性耗尽进样技术,对盐酸异丙嗪和磷酸可待因同时测定的方法进行了研究。考察了pH值、有机溶剂、SDS浓度、进样时间、进样电压等实验条件对分离效果的影响。最佳实验条件为:缓冲体系16%乙腈+80 mmol/L SDS+20 mmol/L NaH2PO4(pH2.4),分离电压为-18 kV,测量波长214 nm,萃取液pH2.4,进样电压10 kV,进样时间100 s。在优化实验条件下,两种物质在8 min内出峰,峰面积RSD不大于4.6%。盐酸异丙嗪、磷酸可待因的线性范围分别为0.50~81.3、0.78~62.5μg/L,检出限分别为0.16、0.12μg/L,相关系数分别为0.998 9、0.998 8。将方法用于可非糖浆中盐酸异丙嗪与磷酸可待因的测定,回收率为96%~106%。     

微芯片毛细管电泳非接触电导法快速测定盐酸倍他洛尔

建立了微芯片毛细管电泳非接触电导检测法快速测定盐酸倍他洛尔滴眼液中盐酸倍他洛尔的含量。探讨了缓冲液类型、浓度、分离电压及进样时间等因素对分离检测的影响。实验采用1.5 mmol·L-1HAc-1.5mmol·L-1Na Ac(p H=4.69)为缓冲溶液,分离电压为2.1 k V,进样时间10.0 s。此条件下于0.7 min内实现了盐酸倍他洛尔的快速分离测定。盐酸倍他洛尔的浓度在5.0~200.0μg·m L-1线性良好(r=0.9997,n=6),检出限为1.0μg·m L-1(S/N=3),RSD为0.8%,样品的加标回收率为100.4%~102.0%。滴眼液中的辅料在该条件下不干扰测定,可成功测定盐酸倍他洛尔滴眼液中盐酸倍他洛尔的含量。     

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.     

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.     

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.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.     

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.