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1.
以5-马来酰亚胺-2-(间马来酰亚胺基苯基)苯并噁唑(DMPB)为荧光试剂,建立了在一定量半胱氨酸(Cys)存在下荧光光度法直接测定还原型谷胱甘肽(GSH)的新方法。研究表明,DMPB荧光很弱,其结构中的两个马来酰亚胺基团都能与GSH或Cys发生反应,生成具有强荧光的产物。并且DMPB与GSH或Cys的生成物(分别称为DMPB-GSH和DMPB-Cys)的最大荧光波长会以不同的速率从eλx/eλm=302/372nm红移至eλx/eλm=310/430 nm,最终均在eλx/eλm=310/430 nm处稳定。在pH 7.0的Na2HPO4-KH2PO4缓冲溶液中和35℃下,DMPB与GSH或Cys反应15 min后,生成的DMPB-GSH的最大荧光波长为eλx/eλm=302/372 nm,且最大荧光强度可以稳定1h,而DMPB-Cys的最大荧光波长为eλx/eλm=310/430 nm,且荧光较弱。利用这一差别,我们选择在eλx/eλm=302/372 nm的荧光波长下测定GSH,完成了0.3倍(Cys∶GSH,摩尔比)Cys存在下对GSH的直接测定,方法线性范围为4.0×10-8~9.6×10-7mol.L-1,检出限(S/N=3)为1.5×10-9mol.L-1。用该法测定了人全血中的GSH,结果令人满意。 相似文献
2.
研究了铽-依诺沙星(enx)-邻菲啰啉(phen)络合物作为荧光探针,荧光猝灭法测定三磷酸腺苷二钠(ATP)的新方法。试验结果表明,在pH 6.7乙酸-乙酸钠缓冲溶液中,eλx=340 nm,eλm=545 nm时,荧光强度的减小值与ATP的浓度在0.1~10.0 mg.L-1范围内呈线性关系,检出限为0.02 mg.L-1。该体系直接用于三磷酸腺苷二钠片剂中ATP含量的测定,标准加入回收率为98.4%~104.0%,相对标准偏差为2.34%。 相似文献
3.
建立了用荧光分光光度法测定苯甘孢霉素含量的新方法.在近中性的介质中,苯甘孢霉素与Au(Ⅲ)发生配合反应生成荧光物质(λex=355 nm,λem=438 nm),在所选定的最佳条件下,苯甘孢霉素在0.40~20 mg·L-1范围内与体系荧光强度呈良好的线性关系,R=0.9982,对浓度为2.0 mg·L-1的苯甘孢霉素连续测定11次,其相对标准偏差(RSD)为2.48%,检出限为O.14 mg·L-1,平均回收率为100.4%.本法可用于片剂和胶囊中苯甘孢霉素含量的测定. 相似文献
4.
研究了2-氯苯甲醛(CBZD)与苯肼的衍生化反应,在pH 1.0的乙醇/水溶液中,2-氯苯甲醛与苯肼形成荧光希夫碱,研究了希夫碱的荧光性质,希夫碱的荧光激发波长eλx=552.0 nm,发射波长eλm=299.2 nm.其荧光强度与2-氯苯甲醛浓度在0~120μg.L-1范围内呈线性关系,检出限为0.2μg.L-1。方法应用于矿泉水、自来水、生理盐水、葡萄糖注射液中2-氯苯甲醛的测定。 相似文献
5.
基于在氨水-氯化铵缓冲介质中,铜(Ⅱ)催化过氧化氢氧化靛蓝胭脂红,导致反应体系的荧光增强,提出了荧光光度法测定痕量铜(Ⅱ)的一种灵敏的方法。在320 nm(eλx)及391 nm(eλm)波长处,反应体系的ΔF(F-F0)与铜(Ⅱ)的质量浓度在0.2~100μg.L-1范围内呈线性关系。方法的检出限(3σ)为0.05μg.L-1。该方法用于大米、面粉和茶叶中铜的测定,测得方法的回收率在96.2%~104.9%之间,测定值的相对标准偏差(n=5)在0.72%~1.5%之间。 相似文献
6.
基于一种新的分子内电荷转移荧光探针1-酮-2-(对二甲氨基苯亚甲基)-四氢萘(简称KDTN)与牛血清白蛋白的结合反应,提出了测定牛血清白蛋白的荧光分光光度法.在激发波长λex)为430 nm,最大发射波长(λem)为530 nm及选定的试验条件下,测定牛血清白蛋白的线性范围为6.8~204.0 mg·L-1,线性回归方程△F=0.583 6.ρ-1.791 7,相关系数为0.999 1,方法的检出限(3S/N)为0.4 mg·L-1,样品的加标回收率为99.9%~102.0%. 相似文献
7.
在近中性条件下,培氟沙星和Eu(Ⅲ)、EDTA反应形成配合物,发生分子内能量转移,产生Eu(Ⅲ)的特征荧光(λem=615 nm,λex=278 nm),据此建立了灵敏、快速的检测培氟沙星的方法,方法线性范围为0.02~1.40 mg·L-1,检出限为0.02 mg·L-1,回收率为96.89/6~100.7%. 相似文献
8.
同步扫描-双波长荧光分光光度法同时测定三种儿茶酚胺类神经递质 总被引:1,自引:0,他引:1
提出了用同步扫描-双波长荧光分光光度法同时测定肾上腺素(EP)、去甲肾上腺素素(NEP)和多巴胺(DA)3种儿茶酚胺类神经递质.试验表明:荧光检测宜选定发射波长(λen)与激发波长(λex)的波长差为70 nm(△λ=λem-λex)的条件下进行同步扫描.在λem为385.0 nm时DA的荧光信号不受EP和NEP的干扰,而EP和NEP相互的干扰,采用双波长荧光检测模式可消除.选择测定NEP的波长对为470.0 nm(λem,1)和531.8 nm(λem,2),测定EP的波长对为500.0 nm(λ'em,1)和445.6 nm(λ'em,2).测得荧光强度与3种儿茶酚胺浓度在320 μg·L-1(EP),640 μg·L-1(NEP)及160μg·L-1(DA)内呈线性关系,检出限(3σ/k)依次为0.20,0.97,0.73 μg·L-1. 相似文献
9.
研究了含硫酰腙试剂1,5-二(2-羟基苯亚甲基)-二氨基硫脲与锌荧光反应的特性及最佳反应条件,建立了荧光光度法测量微量锌的新方法。在pH4.70的HOAc-NaOAc溶液中,试剂与Zn2+形成物质的量之比为1∶1的配合物,在最大激发波长eλx=400nm和最大发射波长eλm=464nm处,锌的线性范围为0~780μg.L-1,检出限为12μg.L-1,线性相关系数为0.9998。方法简便快速地用于含锌食盐、人发中锌的测定。 相似文献
10.
在pH 7.0的磷酸氢二钠-磷酸二氢钾缓冲溶液中,四羧基铁酞菁(FeTCPc)能催化过氧化氢氧化L-酪氨酸,形成荧光二聚体,据此提出了荧光光度法测定水中过氧化氢的方法。在激发波长(λex)320nm与发射波长(λem)410nm处,反应体系的ΔF(F-F0)与过氧化氢的浓度在7.6×10-7~2.7×10-5 mol.L-1之间呈线性关系,方法的检出限(3s/k)为5.2×10-8 mol.L-1。以此方法对两种水样进行分析,测得回收率在96.5%~96.9%之间,测定值的相对标准偏差(n=5)在1.0%~2.8%之间。 相似文献
11.
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
12.
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
13.
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
14.
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
15.
Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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. 相似文献
16.
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
17.
N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
18.
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
19.
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
20.
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