共查询到20条相似文献,搜索用时 62 毫秒
1.
建立了一种以牛肉中肌肽为代表,反相分离测定亲水性物质的方法.选用丙基酰胺键合硅胶亲水作用色谱柱,反相分析测定牛肉中亲水性成分-肌肽的含量,样品无需衍生处理.结合HPLC-MS联用技术确定了保留时间为10.276~10.609min的色谱峰就是肌肽峰.将该色谱柱与常规C18色谱柱进行对比后发现,该色谱柱对L-肌肽的保留能... 相似文献
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乌骨鸡肌肉中肌肽的鉴定与测定 总被引:2,自引:0,他引:2
肌肽是具有抗氧化、抗衰老等多种活性的功能性二肽. 建立了一种高效液相色谱测定鸡肌肉中肌肽的新方法, 该法采用NH2柱分离, 样品无需衍生, 操作简便. 通过该法和HPLC-MS 联用技术鉴定了乌骨鸡肌肉中存在肌肽, 同时比较乌骨鸡和普通白洛克鸡肌肉中肌肽的量. 结果表明: 该法适合于肌肉中肌肽的测定, 测定结果显示, 乌骨鸡肌肉中肌肽量约0.45%, 普通白洛克鸡肌肉中约0.22%. 乌骨鸡肌肉中肌肽量显著高于普通白洛克鸡, 这表明肌肽可能是体现乌骨鸡滋补营养作用的主要成分之一. 相似文献
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柱前衍生非水毛细管电泳分离钴、镍和铜 总被引:2,自引:0,他引:2
提出柱前衍生非水毛细管电泳分离金属离子的方法.应用新合成的2-(6-甲基-2-苯并噻唑偶氮)-5-二乙胺基酚作为柱前衍生试剂,乙醇和N,N-二甲基甲酰胺为非水溶剂,在6min内实现了钴、镍和铜的分离,灵敏度高,检测限分别为9.18×10-8mol/L、2.79×10-7mol/L和4.47×10-7mol/L.考察了柱前衍生条件、非水溶剂配比以及分离参数对分离的影响. 相似文献
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建立了一种同时测定动物源提取物中肌肽(Carnosine)和鹅肌肽(Anserine)含量的超高效液相色谱-电喷雾串联三重四极杆质谱(UHPLC-ESI-MS/MS)分析方法。采用超高效液相分离系统,借助Inertsil Amide HP色谱柱(2. 1 mm×100 mm,3μm)以0. 1%乙酸水溶液-乙腈为流动相,梯度洗脱分离,利用峰面积外标法定量。经过优化,肌肽和鹅肌肽在1. 95~500μg/L质量浓度范围内与峰面积呈良好的线性关系,相关系数(r)均大于0. 998。肌肽和鹅肌肽的检出限分别为0. 12、0. 47μg/L。以低浓度低聚肽原料为基质,在低、中、高3个加标浓度下,肌肽的回收率为99. 3%~109%,相对标准偏差(RSD,n=6)为0. 98%~1. 1%;鹅肌肽的回收率为100%~113%,RSD为1. 0%~1. 1%。该法前处理简单、快速,重现性好,准确度高,适用于动物源食物提取物中肌肽和鹅肌肽的同时快速检测。 相似文献
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以邻苯二甲醛(OPA)和3-巯基丙酸为衍生试剂,建立了柱前衍生高效液相色谱(HPLC)测定曲格列汀中(R)-3-氨基哌啶含量的分析方法。(R)-3-氨基哌啶与衍生剂在碱性(p H 10.5)条件下于室温反应30s,进行柱前衍生,并利用高效液相色谱-质谱对衍生产物进行定性分析。采用YMC-Triart C18色谱柱(150 mm×4.6 mm,5μm)分离,流动相采用0.05 mol/L乙酸钠(p H 6.0)-甲醇溶液,梯度洗脱,流速1.0 mL/min,检测波长331 nm,柱温30℃。(R)-3-氨基哌啶质量浓度在0.08~2.0μg/mL范围内线性关系良好(r=0.9993),定量限为1.6 ng,加标回收率在98.0%~106.9%之间,相对标准偏差(RSD)为2.8%。该方法可用于曲格列汀中(R)-3-氨基哌啶含量测定。 相似文献
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2,4-二硝基氟苯柱前衍生法测定植物中谷氨酸脱羧酶的活力 总被引:4,自引:0,他引:4
建立了2,4-二硝基氟苯(FDNB)柱前衍生反相高效液相色谱紫外检测法测定植物中谷氨酸脱羧酶(GAD)活力的方法.利用GAD催化L-谷氨酸脱羧转变成γ-氨基丁酸(CABA)的性质,用FDNB柱前衍生GABA,HPLC Lichrospher C18色谱柱分离,在360 nm下检测衍生物,从而得到生成GABA的含量,及不同植物组织中的GAD活力.本方法的线性范围0.2~5 g/L GABA(r=0.9954),精密度RSD为0.21%、回收率高,且衍生化产物在一个月内都能保持稳定.用本方法测定得出稻米和茶叶中均有一定的GAD活力.在稻米组织中,GAD主要分布在米胚芽中,米糠也具有相对较高的GAD活性,为开发富含GABA的糙米食品提供了依据. 相似文献
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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%. 相似文献
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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. 相似文献
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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. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
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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. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
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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. 相似文献
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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. 相似文献
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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 SN2 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. 相似文献
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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. 相似文献