反相高效液相色谱法测定对虾组织中噁喹酸残留

建立了测定对虾血淋巴、肌肉和肝胰腺等组织中噁喹酸含量的反相高效液相色谱法。采用乙腈提取对虾血淋巴、肌肉、肝胰腺和鳃组织中噁喹酸,色谱柱为Aglient Zorbax SB-C18柱(150×4.6mm,5μm),以乙腈-0.01mol·L-1四丁基溴化铵(磷酸调节pH为2.75)为流动相,流速1.0mL·min-1,荧光检测器检测。噁喹酸在0.002~10μg·mL-1范围内线性关系良好,相关系数R2=0.9996~0.9999。加标回收率为84.70%~90.60%,日内、日间精密度(RSD)分别为1.60%~4.02%、2.91%~4.73%,定量限分别为0.02μg·mL-1、0.01μg·g-1、0.02μg·g-1和0.02μg·g-1。该方法操作简单,重现性好,适用于对虾样品中噁喹酸含量的分析。     

高效液相色谱-串联质谱法测定兽药粉剂中18种磺胺类违禁添加药物

建立了非磺胺类兽药粉剂中磺胺二甲嘧啶、磺胺醋酰、磺胺甲噻二唑、磺胺氯哒嗪、磺胺甲基异唑、磺胺噻唑、磺胺-6-甲氧嘧啶、磺胺甲基嘧啶、磺胺邻二甲氧嘧啶、磺胺吡啶、磺胺对甲氧嘧啶、磺胺甲氧哒嗪、磺胺苯吡唑、磺胺间二甲氧嘧啶、磺胺二甲异唑、磺胺喹啉、磺胺嘧啶、甲氧苄氨嘧啶18种磺胺及其增效剂等违禁添加药物的超高效液相色谱-串联质谱分析方法。样品经甲醇-水(90∶10)萃取后,以乙腈(含0.1%甲酸)和水(含0.1%甲酸)为流动相,C18(2.1 mm×150 mm,5μm)色谱柱分离后,在正离子模式下以电喷雾串联质谱仪进行测定。方法的线性范围为50~2 000μg/kg,18种磺胺类药物残留的检出限为10μg/kg。在50,200,1 000μg/kg 3个浓度水平下进行加标回收实验,平均回收率为86.8%~115%,相对标准偏差为1.0%~9.7%。     

同步荧光法测定复方新诺明中磺胺甲基异噁唑和甲氧苄氨嘧啶的含量研究

本文采用同步荧光技术对复方新诺明中有效成份磺胺甲基异噁唑和甲氧苄氨嘧啶进行测定,在△λ分别为72nm和94nm的条件下,测定样品中所含有效成份相当于标示量的95.12％～105.68％;回收率为95.5％～98.1％;线性范围磺胺甲基异噁唑为0.125～4.00μg/ml。甲氧苄氨嘧啶为0.125～3.00μg/ml;相关系数分别为0.9976和0.9978.不经分离和掩蔽直接连续测定,效果良好。     

超高效液相色谱-串联质谱法同时测定化妆品中的22种磺胺类药物

建立了同时测定化妆品中22种磺胺类药物(磺胺胍、磺胺、磺胺嘧啶、磺胺二甲异嘧啶、磺胺醋酰、磺胺噻唑、磺胺吡啶、磺胺甲基嘧啶、磺胺对甲氧嘧啶、磺胺二甲噁唑、磺胺二甲嘧啶、磺胺甲噻二唑、磺胺甲氧哒嗪、琥珀酰磺胺噻唑、磺胺氯哒嗪、磺胺甲基异噁唑、磺胺间甲氧嘧啶、磺胺邻二甲氧嘧啶、磺胺二甲异噁唑、磺胺间二甲氧嘧啶、磺胺喹噁啉、磺胺硝苯)的超高效液相色谱-串联质谱分析方法。膏霜、水剂、散粉、香波、唇膏等不同类型的化妆品样品经超声提取后,以Waters ACQUITY UPLC BEH C18色谱柱(50 mm×2.1 mm,1.7μm)分离后进行UPLC/MS/MS多反应监测模式下的定性及定量分析。22种磺胺类药物的方法检出限为3.5~14.1μg/kg;在低、中、高的3个添加水平范围内的平均回收率为80.3%~103.6%;日内精密度均小于12%,日间精密度均小于15%。     

牛奶中12种磺胺类药物残留的高效液相色谱测定方法

建立了高效液相色谱(HPLC)检测牛奶中12种磺胺类药物(磺胺二甲基嘧啶、磺胺间甲氧嘧啶、磺胺甲噁唑、磺胺对甲氧嘧啶、磺胺喹噁啉、磺胺氯哒嗪、磺胺氯吡嗪、磺胺嘧啶、磺胺噻唑、磺胺甲基嘧啶、磺胺甲噻二唑、磺胺地索辛)残留的方法,考察了样品的提取、净化及色谱分析条件。牛奶样经乙酸乙酯提取、固相萃取净化后上机分析,11种磺胺药物标准曲线在10~800μg/L,SM2在5~200μg/L质量浓度范围内相关系数r>0.999,回收率为76%~106%,相对标准偏差小于15.9%。检出限为5~8μg/L,定量下限为14~27μg/L。     

甲氧苄啶分子印迹涂层搅拌棒在复杂样品痕量甲氧苄啶和磺胺药物分析中的应用(英文)

研制了甲氧苄啶分子印迹吸附萃取搅拌棒涂层,并应用于复杂样品中痕量甲氧苄啶和磺胺药物的分析。分子印迹涂层的厚度约为21.5μm,相对标准偏差为5.9%(n=10),涂层均匀、致密,具有良好的热稳定性和化学稳定性。分子印迹涂层的萃取容量是非印迹涂层萃取容量的1.7倍,分子印迹涂层对抗菌增效剂、磺胺药物、三嗪化合物和甲氨蝶呤都表现出良好的选择性吸附萃取能力。建立了分子印迹吸附萃取搅拌棒联用高效液相色谱的分析方法,成功应用于加标尿样和血浆中痕量甲氧苄啶的分析,线性范围为5～200μg/L,检出限为1.6μg/L,在尿样和血浆中的回收率范围分别为84.5%～91.7%和71.9%～85.1%,标准偏差分别为2.9%～4.4%和3.0%～7.3%。该方法还应用于加标牛奶中痕量磺胺药物的分析,线性范围为10～200μg/L,检出限在4.5～6.1μg/L之间,回收率为83.2%～110.2%,标准偏差为4.1%～8.0%.     

同步荧光法测定复方新诺明中磺胺甲基异恶唑和甲氧苄氨嘧啶的含量…

本文采用同步荧光技术对复方新诺明中有效成份磺胺甲基异恶唑和甲氧苄氨嘧啶进行测定，在△λ分别为７２ｎｍ和９４ｎｍ的条件下，测定样品中所含有效成份相当于标示量的９５．１２％－１０５．６８％；回收率为９５．５％－９８．１％；线性范围磺胺甲基异恶唑为０．１２５－４．００μｇ／ｍｌ。甲氧苄氨嘧啶为０．１２５－３．００μｇ／ｍｌ；相关系数分别为０．９９７６和０．９９６８。不经分离和掩蔽直接连续测定，效果良好。     

超高效液相色谱-串联质谱法测定动物源性食品中的三甲氧苄氨嘧啶

建立了一种超高效液相色谱-串联质谱法(UPLC-MS/MS)测定多种基质(鸡肉、鱼肉、鸡肝、鸡蛋和牛奶)中三甲氧苄氨嘧啶的分析方法。样品用甲酸-乙腈(1:9,V/V)溶液提取,正己烷除脂净化,Acquity UPLC BEH C18柱(1.7μm,2.1 mm×50 mm)分离,以甲醇和体积分数0.1%甲酸5 mmol乙酸铵(V/V)作为流动相进行梯度洗脱,电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测。结果表明:三甲氧苄氨嘧啶质量浓度在1.25~15.0μg/L范围内线性关系良好(r≥0.99)。方法的定量限(信噪比为10)为5.0μg/kg,在5.0,10.0μg/kg添加浓度的回收率为61.2%~108.5%,相对标准偏差(n=6)在1.4%~9.8%之间。方法适合于多种基质中三甲氧苄氨嘧啶的测定。     

赛庚啶-分子印迹聚合物的制备及其固相萃取研究

以赛庚啶为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,通过优化致孔剂、单体及模板与单体摩尔比等因素,合成了对赛庚啶具有高选择性的分子印迹聚合物,其表面积达24.9 m2/g。制备的印迹聚合物固相萃取小柱(MISPE)依次以甲醇和水活化小柱,水溶液上样,水和甲醇依次洗涤,氨化甲醇(5∶95,V/V)洗脱,赛庚啶在制备MISPE小柱上的回收率为94.0%,而非分子印迹小柱(NISPE)的回收率仅为38.9%;MISPE结合赛庚啶的容量达8.8 mg/g,印迹因子约为2.32。在优化的固相萃取条件下,10 mg/L赛庚啶、阿米替林、磺胺嘧啶和甲氧苄啶混合标准溶液上样,进行选择性实验。以0.05%戊烷磺酸钠溶液和乙腈为流动相,梯度洗脱,在MISPE小柱上,与CYP化学结构差异较大的磺胺嘧啶和甲氧苄啶回收率均小于10%,结构相似的阿米替林回收率达70%,赛庚啶回收率大于90%;4种分析物在NISPE小柱上的回收率均小于30%。制备的MISPE小柱应用于畜禽饮用水样中赛庚啶的分离富集和分析测定,方法回收率为80.5%~97.7%,检出限达0.01 mg/L。     

复方磺胺甲噁唑分散片溶出度方法学研究

建立准确、快速的溶出度测定方法.紫外双波长分光光度法.线性范围磺胺甲噁唑浓度在2.770～16.62μg/mL范围内,r=0.9993;甲氧苄啶浓度在1.260～7.560 μg/mL范围内,r=0.9994;平均回收率分别为磺胺甲噁唑99.65±0.10%,甲氧苄啶100.8±0.55%.本方法能准确、快速地测定复方磺胺甲噁唑分散片的溶出度.     

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%).