首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
王桂芬  朴元哲 《分析化学》1998,26(12):1490-1493
应用循环伏安法、微分脉冲伏安法对多菌灵在破碳电极上的电化学行为及其测定进行了研究。在pH=9.0的2mol/L NH3-NH4Cl底液中,对其进行循环伏安扫描,发现于0.61V(vs.Ag/AgCl)产生一灵敏的氧化峰。微分脉冲伏安法殉菌灵的检测限为4×10^-8mol/L。多菌灵的浓度在5.0×10^-7 ̄1.0×10^-5mol/L间与微分脉冲伏安峰电流呈线性关系(r=0.9942)。对于1×  相似文献   

2.
示差脉冲伏安法测定黄酒中的酪氨酸   总被引:3,自引:0,他引:3  
本文研究了硼砂介质中镍与酪氨酸络合物的示差脉冲吸附伏安特性,实验了仪器参数对示差脉冲阴极吸附伏安法的影响,在最佳条件下络合物峰电流与酪氨酸浓度在2.0×10^-7~4.0×10^-5mol.L^-1范围内有线性关系,并以此法测定了黄酒中酪氨酸的含量。  相似文献   

3.
头孢噻肟钠的降解及其产物伏安行为的研究   总被引:18,自引:1,他引:18  
头孢噻肟钠在NaOH溶液中降解后,于0.1mol/LNaOH中得一灵敏的吸附伏安原峰,Ep=-0.78V(νsAg/AgCl),ip与头孢噻肟钠浓度在1.0×10^-^9-1.0×10^-^8,1.0×10^-^8-1.0×10^-^7,1.0×10^-^7-1.0×10^-^6mol/L范围内呈线性关系,检出限为5.0×10^-^1^0mol/L。用多种电化学手段研究其降解产物的伏安行为,测定了  相似文献   

4.
镍—脯氨酸络合物在硼砂中的示差脉冲吸附伏安法   总被引:2,自引:0,他引:2  
张晓丽  任艺兵 《分析化学》1995,23(12):1422-1424
本研究了硼砂介质中镍与脯氨酸络合和的示差脉冲吸附伏安特性,实验了仪器参数对示差脉冲吸附伏安法的影响,发现络合物峰电流与脯氨酸浓度在5.0×106-7-2.0×10^-5mol/L内有线性关系,并测定了中药中脯氨酸的量 。  相似文献   

5.
大蒜中抗坏血酸的半微分伏安法测定   总被引:2,自引:0,他引:2  
将工作电极直接插入大蒜瓣中,采用半微分伏安法研究了抗坏血酸的测定方法。用微铂盘电极(直径300 μm)作为工作电极,在pH6.8的磷酸氢二钠-柠檬酸介质中,抗坏血酸在7.0×10-2~3.2×102mg/L范围内与半微分伏安曲线阳极峰的峰高呈线性关系,其最低检出浓度为4.0×10-2mg/L。利用t检验和F检验法,将所研究方法与溶液中的标准加入法相比,对相同样品的测定结果无显著性差异。  相似文献   

6.
微分脉冲伏安法测定生物素   总被引:1,自引:0,他引:1  
用微分脉冲阳极伏安法研究了生物素的电化学行为,用金电极作工作电极,在pH3.59的HAc-NaAc介质中,生物素的峰电位为0.46V,生物素浓度在1.0×10-6~2.0×10-5mol/L范围内与峰高呈线性关系。本法应用于含生物素样品的分析,可以不经分离,直接测定。此外,还用循环伏安法研究了电极反应的可逆性。  相似文献   

7.
大蒜中抗坏血酸的半微分伏发法测定   总被引:2,自引:0,他引:2  
韩树波  袁倬斌 《分析化学》1997,25(3):338-340
将工作电极直接插入大蒜瓣中,采用半微分伏安法研究了抗坏血酸的测定方法。用微铂盘电极作为工作电极,在ph6.8的磷酸氢二钠-柠檬酸介质中,抗坏血酸在7.0×10^-2-3.2×10^2mg/L范围内与半微分伏安曲线阳极峰的峰高呈线性关系,其最低检出浓度为4.9×10^2mg/L。  相似文献   

8.
聚吡咯碳糊电极的研制及应用   总被引:6,自引:0,他引:6  
杨继生 《分析化学》1998,26(7):847-849
研制了聚吡咯电极,探讨了该电极的性能和实用性,实验结果表明,该电极可用于伏安法快速测定L-抗坏血酸,在0.1mol/LKNO3底液中,线性范围为1.0×10^-11~9.0×10^-9mol/L检测限为5.0×10^-12mol/L,电极具有具有良好的重现性和高选择性,响应迅速,使用寿命3个月以上。  相似文献   

9.
程琼  彭国治 《分析化学》1998,26(11):1315-1319
报道了一种抗真菌治疗新药酮康唑的吸附行为及其测定。该药物在玻碳电极上预富集后,用示差脉冲伏安法测定,其响应电流与药物浓度在2.0×10^-10-1.0×10^--5mol/L范围内呈线性关系;检屈限为4.0×10^-11mol/L。可用于尿和血清样品中药物含量的测定。  相似文献   

10.
银微盘电极上头孢氨苄降解产物的伏安行为及其应用   总被引:9,自引:3,他引:9  
方宾  朱英贵 《分析化学》1997,25(5):505-509
基于头孢氨苄降解产物中含有巯基,能与Ag^+生成难溶化合物的特性,在银微盘电极上研究了CEX降解产物的伏安行为,探讨了电极反应的机理。运用示差脉冲溶出伏安法,在0.1mol/L HAc-NaAc介质中,CEX降解产物的还原峰电流与CEX浓度于8.0×10^-8-7.0×10^-6mol/L范围内呈良好线性关系;检测限为1.0×10^08mol/L;测定了头孢氨苄胶囊中CEX含量为92.0%,与药典  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.
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.
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.
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.
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   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
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   

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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号