反相高效液相色谱-蒸发光散射检测法测定安宫牛黄胶囊中的胆酸

应用反相高效液相色谱-蒸发光散射检测法对安宫牛黄胶囊中的胆酸含量进行了测定。色谱柱用JASCO C18柱(250 mm×4.6 mm i.d.,5 μm),流动相为甲醇-0.1%(体积分数)醋酸水溶液(体积比为9∶1),流速1.0 mL/min,柱温为室温;蒸发光散射检测器漂移管温度40 ℃,载气（N2)流速4.0 L/min。在上述条件下测得胆酸的进样量为0.50-5.02 μg时线性关系良好(r=0.999?3),最低检测限达到0.05 μg,平均加样回收率为97.1%。该方法快速简捷,精密度高,重现     

高效液相色谱-蒸发光散射法测定牛黄中多种有效成分含量及其质量相关性研究

建立高效液相色谱-蒸发光散射法(HPLC-ELSD)同时快速测定牛黄中7种组分的含量的方法。色谱柱为UltimateAQ-C18柱,流动相为乙腈-0.2%甲酸水溶液,梯度洗脱,流速1mL/min;蒸发光散射检测器参数:漂移管温度100℃,载气(N2)流速1.9L/min。在选定色谱条件下,胆固醇、各种胆汁酸及其钠盐峰形良好且能达到很好地分离。各组分色谱峰峰面积的对数与浓度的对数呈良好线形关系(r0.9972);标准加入回收率为98.8%～112.7%;7种组分的最低检出限为0.001～0.007g/L。本方法可简便、快速地同时检测不同牛黄样品中7种组分的含量并可表征不同牛黄样品的质量,从而为该名贵药材的质量控制提供更全面的依据和参考。     

高效液相色谱-蒸发光散射检测法测定肉苁蓉中的甜菜碱

建立了高效液相色谱-蒸发光散射检测法测定中药材肉苁蓉中甜菜碱含量的方法。采用Waters Spherisorb S5 NH2 色谱柱(250 mm×4.6 mm, 5 μm),柱温25 ℃,流动相为0.1%（体积分数）三氟乙酸水溶液-甲醇(体积比为15∶85）,流速0.6 mL/min。蒸发光散射检测器参数：漂移管温度90 ℃,喷雾器温度45 ℃,载气（氮气）压力110 kPa（16 psi）。结果表明,该法具有良好的线性关系,同时,不同种肉苁蓉的测定结果表明：管花肉苁蓉不含甜菜碱,因此建议将甜菜碱作为标志物质来鉴别正品肉苁蓉(Cistanche deserticola Y. C. Ma)和管花肉苁蓉(C. tubulosa (schenk) R. Wight)。     

高效液相色谱法测定保健食品和饮料中的阿斯巴甜

建立了保健食品和饮料中的甜味剂阿斯巴甜的高效液相色谱快速测定方法.固体样品用纯水超声提取;饮料样品超声脱气.取适量提取液或饮料样品,经0.45 μm滤膜过滤后,取20 μL进样色谱柱分析.色谱条件:分离柱为C18柱(250mm×4.6 mm i.d.,10μm),柱温35℃,流动相为V(10 mmol/L KH2PO4,pH 3.50):V(乙腈)=80:20,流速1 mL/min,检测波长210 nm.本法线性范围为0～16 μg,最低检出量为0.0024 μg,回收率为92.3%～102%.相对标准差小于1.6%.本法准确度和精密度均能满足保健食品和饮料中阿斯巴甜测定的要求.     

高效液相色谱-蒸发光散射检测法测定合成产物中的果糖棕榈酸酯

建立了反相高效液相色谱-蒸发光散射检测（HPLC-ELSD）测定合成产物中的果糖棕榈酸单酯和果糖棕榈酸双酯的方法。HPLC-ELSD条件为：反相Prevail C18色谱柱,柱温为30 ℃,流动相为乙酸乙酯-甲醇-水（体积比为59.4∶30∶10.6）,流速为1 mL/min,ELSD漂移管温度为73.8 ℃,载气流速为2 L/min。在该色谱条件下,果糖棕榈酸单酯及果糖棕榈酸双酯在进样量为1～15 μg时,与其峰面积的线性关系良好,相关系数r2均大于0.9996。     

响应面优化-HPLC-ELSD法测定明胶型凝胶糖果中的磷脂酰丝氨酸

建立了测定明胶型凝胶糖果中磷脂酰丝氨酸的高效液相色谱分析方法。样品经酸法水解,石油醚萃取,浓缩吹干后,用氯仿-甲醇溶液(9:1,V:V)定容。在单因素试验基础上,以水解温度、水解时间和盐酸浓度为影响因素,通过Box-Benhnken响应面优化法确定了最佳酸法水解条件:水解温度60℃,水解时间17 min,盐酸浓度1. 8 mol/L。色谱柱选用硅胶柱(4. 6 mm×250 mm,5μm),以正己烷/异丙醇/水/乙酸/三乙胺(5:81:14:1. 5:0. 08,体积比)为流动相,流速1. 0 mL/min,柱温40℃。蒸发光散射检测器参数:漂移管温度100℃,载气(N2)流速2. 0 L/min。磷脂酰丝氨酸在25～300 mg/L范围内相关系数为0. 9999,回收率为93. 5%～96. 0%,检出限为0. 05 mg/g,定量限为0. 17 mg/g。该方法适用于明胶型凝胶糖果中磷脂酰丝氨酸的含量测定。     

高效液相色谱-蒸发光散射检测法测定蛋黄卵磷脂的含量

建立了蛋黄磷脂中卵磷脂（即磷脂酰胆碱,PC)的高效液相色谱-蒸发光散射检测（HPLC-ELSD）的测定方法。以Nov a-Pak Silica 60A硅胶柱(3.9 mm i.d.×150 mm,4 μm)为分离柱,正己烷-异丙醇-3%冰醋酸水溶液(体积比为35∶65 ∶8)为流动相，等度洗脱,流速1.0 mL/min,柱温30 ℃。蒸发光散射检测器漂移管温度50 ℃,雾化气(空气)压力350 kPa。在上述条件下测得PC在0.16~1.61 g/L范围内线性关系良好(r2=0.9979),检测限为0.64 μg,方法的精密度为3.2%(n=5),回收率为98.2%~128.2%。将该方法用于实际样品的测定,获得了令人满意的结果。该方 法预处理简单,分析速度快,可用于蛋黄磷脂中卵磷脂的测定。     

高效液相色谱-蒸发光散射检测法测定玉屏风胶囊中黄芪甲苷的含量

建立高效液相色谱-蒸发光散射检测法测定玉屏风胶囊中黄芪甲苷的含量.采用Phenomenex C18(4. 6mm×250 mm i. d. ,5μm)色谱柱,柱温为35℃,以乙腈-水(35∶65)为流动相,以蒸发光散射检测器进行检测.以峰面积的常用对数(Y)对进样量的常用对数(X)进行线性回归,回归方程为Y=1. 6709 X+14. 2699(r=0. 9998),线性范围为1～19μg.加标回收率为86. 7%～96. 2%,测定结果的RSD为0. 22%(n=7).方法准确、可靠、重复性好,可有效控制玉屏风胶囊的质量.     

反相高效液相色谱法测定大黄药材中游离及结合型蒽醌类衍生物的含量

建立了同时测定大黄药材中蒽醌类衍生物含量的RP HPLC法。色谱柱为HypersilC1 8柱 (2 5 0mm×4 6mmi.d .,1 0 μm) ,流动相为甲醇 乙腈 水 (3∶5∶2 ,磷酸调pH 2 .8) ,流速为 1 .0mL min ,柱温为 2 5℃ ,检测波长为 2 2 5nm。在此色谱条件下 ,各组分在 2 0min内均得到良好分离。平均回收率为 98.83 %～ 1 0 0 .9% ;相对标准偏差 0 .68%～ 1 .5 8%。     

鱼腥草中3种有效成分含量的测定

建立鱼腥草不同品种、不同部位绿原酸、芸香苷和槲皮素的测定方法. 以90% EtOH为溶剂, 采用索氏提取器提取, 利用HPLC测定3种活性成分的含量. 采用DiamonsilTMC18 (4.6 mm×150 mm, 5 μm)为色谱柱, 流动相分别为0.06 mol/L V(NaH2PO4)∶V(MeOH)＝7.3∶2.7、 V(MeOH)∶V(H2O)∶V(HAc)＝48∶50∶2, 流速为1 mL/min, 绿原酸检测波长为326 nm, 芸香苷和槲皮素为254 nm. 绿原酸、芸香苷、槲皮素的线性范围分别为4.6～30.7 μg/mL、 0.30～7.5 μg/mL、 0.034～0.85 μg/mL, 平均回收率和RSD分别为99.3%、 1.0%, 98.9%、 1.6%, 98.7%、 0.7%. 该方法可用于鱼腥草原料选择和制剂质量的控制.     

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.     

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.     

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.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).