高效液相色谱检测反应香精中的2-氨基-N-甲基-5-苯基咪唑并吡啶(PhIP)方法研究

建立了用高效液相色谱快速检测反应香精中2-氨基-N-甲基-5-苯基咪唑并吡啶的方法. 反应香精中的2-氨基-N-甲基-5-苯基咪唑并吡啶用二甲基甲酰胺直接超声振荡提取; 高效液相色谱的色谱柱为Eclipse XDB-C18 (250 mm×4.6 mm, 5 μm); 流动相为V(二甲基甲酰胺)∶V(甲醇)∶V(水)=8∶50∶42; 流速为0.5 mL/min; 光电二极管阵列检测器检测波长为UV-327 nm. 10种反应香精中均未检出该种物质, 回收率为78.9%～85.9%, 检出限为19.2 ng/mL.     

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.     

高效液相色谱法测定水中硝基苯和苯胺含量

建立了高效液相色谱直接进样快速分析水样中苯胺和硝基苯的方法.操作条件为:进样量5 μL;流速1 mL/min;流动相为V(乙腈)∶ V(3.85 g/L乙酸铵+3 g/L乙酸)=65∶ 35混合液;苯胺用荧光分析,λex/λem =280/340 nm;硝基苯用紫外分析,波长为262 nm;分离柱为Eclipse XDB2-C8 柱(150 mm×4.6 mm, 5 μm);测试时间为3.2 min;样品前处理方法:1.0 mL水样与1.0 mL甲醇混匀,用微孔滤膜(0.45 μm, 有机系)过滤.苯胺和硝基苯标准曲线的线性相关系数均 >0.999.测试苯胺、硝基苯时,仪器精密度分别为1.56%和0.13%.方法的回收率在89%～110%之间.仪器对苯胺和硝基苯的检出上限分别是50和200 mg/L; 苯胺和硝基苯的方法检出限分别是18和21 μg/L.     

HPLC测定藏药香菊活血丸中士的宁的含量

采用RP-HPLC法,色谱柱:Symmetry C18 (5 μm,4.6 mm×250 mm);流动相:V(甲醇)∶V(0.025 mol/L KH2PO4 (pH 2.8))=20∶80;检测波长260 nm;流速:0.7 mL/min,进样量10 μL,对香菊活血丸中士的宁进行含量测定.结果显示士的宁在0.004～0.128 μg (r=0.9993)范围内有良好的线性关系;平均回收率为101.73% (平均RSD=1.153%).本方法可用于香菊活血丸中士的宁的质量控制.     

高效液相色谱法测定盐酸甲氯芬酯胶囊的含量

建立了用高效液相色谱测定盐酸甲氯芬酯胶囊含量的方法.采用Hypersil C18柱(5 μm,4.6 mm i.d.×200 mm),流动相为V(乙腈)∶V(0.12% NH4HCO3-0.50%三乙胺)溶液＝33∶67 (甲基磺酸调pH至3.0),流速: 1.0 mL/min,检测波长为225 nm.盐酸甲氯芬酯的线性范围为1.632～163.2 μg/mL,平均回收率为99.67%,RSD=1.8% (n=9).     

加速溶剂萃取-高效液相色谱法测定土壤中咪唑乙烟酸残留量

建立了加速溶剂萃取-高效液相色谱法测定土壤中咪唑乙烟酸除草剂残留量的检测方法.加标土壤样品以V(甲醇)∶V(冰乙酸)＝5∶1作提取剂,在温度50 ℃,压力9 MPa下静态萃取10 min,提取物用高效液相色谱二极管阵列检测器进行分析.色谱柱为ODS柱,流动相为V(甲醇)∶V(水)∶V(冰乙酸)＝50∶46∶4,流量: 1 mL/min;检测波长: 254 nm.结果表明: 1和10 μg/g的加标回收率分别为90%和86%,相对标准偏差分别为4.1%和4.5%,检出限可达0.006 μg/g.     

固相萃取RP-HPLC测定小鼠肝脏组织中的多沙唑嗪

研究建立了小鼠肝脏组织中多沙唑嗪的反相高效液相色谱测定方法. 肝组织样品经过匀浆、提取、C18固相萃取小柱富集净化后, 在YMC C18色谱柱(4.6 mm i.d.×250 mm, 5 μm)上, 以V(甲醇)∶V(0.02 mol/L KH2PO4) ＝70∶30, pH 3.0为流动相, 流速0.6 mL/min, 检测波长246 nm对多沙唑嗪进行测定. 结果表明, 肝脏组织中的多沙唑嗪在0.5～10 μg/mL范围内与峰面积呈良好线性关系. 平均回收率为91.0%, RSD为3.3%. 检出限为1 ng. 方法操作简便, 重现性好, 适用于肝脏组织中多沙唑嗪药物的浓度测定及代谢研究.     

高效液相色谱法测定功能性红曲米粉中的青霉素G钠

采用高效液相色谱法测定了功能性红曲米粉中的青霉素G钠,选用Aichrom Bond-AQ C18(250 mm×4.6 mm i.d.,5μm)色谱柱,V(甲醇)∶V(水)=30∶70为流动相,检测波长为215 nm,流速1 mL/min,结果青霉素G钠在1.0~500 mg/L范围内具有良好的线性关系,r=0.9999;回收率为99.0%~107.5%;检出限为0.2 ng。     

肉类及水产品中四环素类抗生素残留量的高效液相色谱测定方法

建立了肉类中土霉素(OTC)、四环素(TC)、金霉素(CTC)残留量的高效液相色谱荧光检测方法.样品经5%HClO4除蛋白后,离心过滤.采用Waters XTerra RP18(5 μm,4.6×150 mm)色谱柱,以V(甲醇):V(CaCl2缓冲液)=30:70(pH 6.6)为流动相,等度洗脱,流速0.8 mL/min,柱温25℃.经CaCl2缓冲液衍生化,在激发波长(Zx)350 nm和发射波长(Zm)520nm处检测土霉素、四环素和金霉素的残留量.结果表明,在此条件下,测得上述3种抗生素在0.09～4.64μg/mL范围内线性良好,土霉素的最小检测限为1.48 ng/mL,四环素为1.20ng/mL,金霉素为2.32 ng/mL,方法的精密度为0.69%～1.23%,加样回收率为64.63%～90.89%.实验证明本方法可用于检测肉类中土霉素、四环素和金霉素的残留量.     

新型除草剂2.5%稻杰的有效成分测定-高效液相色谱法

采用高效液相色谱测定了新型除草剂2.5%稻杰(FENCER)的有效成分,用外标法进行定量分析.条件为:Waters Symmetry C8色谱柱;流动相包括V(乙腈)∶V(水)∶V(1% H3PO4=60∶40∶0.1;检测波长为285 nm;流速为1.0 mL/min,柱温为室温;进样量为10 μL;实验结果表明,样品平均回收率为98%,精密度为0.13%.     

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.     

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.     

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.     

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.     

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.     

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%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

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.