聚氯乙烯膜依诺沙星选择电极的研制与应用

以盐酸依诺沙星与四苯硼酸盐生成的分子缔合物制成新型PVC膜依诺沙星选择电极,应用于依诺沙星药片的含量测定。在pH 2.2～6.5范围内,电极的能斯特响应范围为5.0×10~(-5)～1.0×10~(-2)mol/L,斜率为58.0mV/pc,检出限为4.2×10~(-6)mol/L。该电极响应速度快,重现性好。3次测定的平均回收率为97.5％,RSD为1.0％,结果与紫外分光光度法基本一致。     

利眠宁-碘铋酸盐修饰碳糊电极的制作及应用

以利眠宁与硝酸铋(物质的量的比为1∶1)的分子缔合物作为电活性物质,研制了利眠宁-碘铋酸盐修饰碳糊电极,该电极对溶液中的利眠宁有良好的线性响应,响应斜率为-58.8 mV/pc,线性范围为6.0×10~(-5)～1.0×10~(-1)mol/L,达4个数量级,检出限为1.0×10~(-5)mol/L,RSD为1.0％～1.4％,加标回收率为98.0％～102％。该电极可用于利眠宁片中利眠宁含量的测定。     

谷氨酸脱羧酶电极与大肠杆菌膜电极的比较研究

本文研究了分别用谷氨酸脱羧酶和大肠杆菌作为催化L-谷氨酸脱羧的酶材料来制作的生物传感器的响应性能。结果表明这两种电极各具特点。谷氨酸脱羧酶电极对底物L-谷氨酸的校正曲线的线性范围为3.16×10~(-4)mol/L～1.0×10~(-2)mol/L。斜率为46mV,响应时间为6～8min电极寿命仅为5天。而大肠杆菌膜电极线性范围为4.22×10~(-4)mol/L～1.78×10~(-2)mol/L,斜率为48.5mV,响应时间为8～9min,电极寿命达34天。这两种电极对底物L-谷氨酸皆具有专一的选择性,且在磷酸吡哆醛的存在下,活性都有所增加。将电极用于味精中L-谷氨酸钠的测定,获得较满意的结果。     

伏安型植物组织生物微电极的研究——茄子组织碳糊微电极的研究

茄子组织生物微电极在儿茶酚测定中表现出了较高的生物催化活性,而对抗坏血酸测定则为稳态响应,这表明该电极能有效地消除抗坏血酸的干扰。该电极的灵敏度高,重现性好,对多巴胺测定的线性范围为5.8×10~(-6)～6.5×10~(-4)mol/L,检出下限为:2.9×10~(-6)mol/L。     

黄芩及其制剂中黄芩素和黄芩甙的

用毛细管区带电泳 -电化学检测法测定了黄芩及其制剂中黄芩素和黄芩甙的含量。研究了电极电位、电解液酸度和浓度、电泳电压及进样时间等对电泳的影响 ,得到了较为优化的测定条件。以直径为300μm的碳圆盘电极为检测电极 ,电极电位为0.90V(vsSCE) ,在100mmol/L硼酸盐缓冲液(pH9.0)中 ,上述两组分在8min内完全分离。黄芩素和黄芩甙浓度与电泳峰电流分别在5.0×10 -7～1.0×10 -3mol/L和1.0×10 -6～1.0×10 -3mol/L范围内呈良好线性 ,检出限分别为2.24×10 -7mol/L和5.48×10 -7mol/L。7次测定分别含5.0×10 -4mol/L黄芩素和黄芩甙试样溶液 ,峰高的相对标准偏差分别为3.53%和4.03%。     

三维荧光光谱法连续测定苯胺、二苯胺和N-甲基苯胺

本文比较了苯胺、二苯胺、N-甲基苯胺的二维荧光光谱和三维荧光光谱。提出了同时测定苯胺,二苯胺和N甲基苯胺的分析方法,它们的浓度分别在2.0×10~(-7)～5.0×10~(-6)mol/L,9.0×10~(-8)～7.4×10~(-6)mol/L,1.3×10~(-7)～2.0×10~(-8)mol/L范围内有良好的线性关系,检出限为1.0×10~(-7)mol/L,8.0×10~(-9)mol/L,1.0×10~(-7)mol/L.相对标准偏差分别为5％,7％,7％.此方法用于混合样品和工业废水的分析,获得较满意的结果.     

肌酐-铜(Ⅱ)体系的电化学氧化及分析应用

肌酐能够和Cu~(2+)生成络合物,该络合物可以吸附于玻碳电极表面,在pH3.50的NH_4Cl-HCl底液中,吸附于电极表面的肌酐-Cu~(2+)络合物在较负的电位下还原为肌酐-Cu~+,当电极向正向扫描时,产生一个灵敏的表面催化波,其峰电流和肌酐的浓度在1.0×10~(-5)～1.0×10~(-8)mol/L范围内有良好的线性关系,其检出限为1.0×10~(-9)mol/L(富集5min).研究了肌酐-Cu~(2+)络合物在玻碳电极上的氧化还原机理,选择了测定肌酐的最佳实验条件,建立了测定肌酐的新的灵敏的方法.     

磷钼杂多酸修饰电极催化还原测定IO_3~-与BrO_3~-的液相色谱电化学研究

本文介绍了1:12磷钼杂多酸(PMo_(12))修饰电极的制备及其对IO_3~-、BrO_3~-的催化还原作用。本文还研究了在涂敷十六烷基三甲基溴化铵的C_(18)键合固定相上IO_3~-与BrO_3~-的分离方法,并采用修饰电极色谱电化学的方法对IO_3~-与BrO_3~-进行定量测定。IO_3~-、BrO_3~-的量分别在8.0×10(-10)～1.0×10~(-7)mol和1.6×10~(-9)～3.0×10~(-7)mol范围内与峰高呈良好的线性关系,检测限分别为4.0×10~(-10)mol与1.0×10~(-9)mol。用本方法测定IO_3~-和BrO_3~-重现性好、线性范围大,是测定IO_3~-与BrO_3~-的一种实用方法。     

钴-5,10,15,20-四(3-甲氧基-4-羟基苯基)卟啉修饰玻碳电极的L-抗坏血酸化学传感器研究

将水合 5,10,15,20-四-(3-甲氧基-4-羟基苯基)钴卟啉(CoTMHPP)修饰在玻碳电极表面,制成CoTMHPP修饰电极.电极稳定性好且灵敏度高,对抗坏血酸有良好的电催化氧化作用,测定线性响应范围为1.0×10(-5)～1.0×10(-2)mol/L,响应时间小于12s.本文研究了电极的性质和应用,并用于药物中抗坏血酸的测定,其测定结果与碘量法一致.     

碳纳米管修饰电极对多巴胺和肾上腺素的电分离及同时测定

研究了多巴胺 (DA)和肾上腺素 (EP)在多壁碳纳米管 (MWNT)修饰电极上的电化学性质 ,发现该修饰电极对神经递质DA和EP有显著的增敏和电分离作用。还原峰电位差达ΔEp=390mV ,可同时测定DA和EP。DA和EP的还原峰电流与其浓度分别在 2 .0× 10 -6～ 1.0× 10 -3 mol/L和 1.0× 10 -6～ 1.0× 10 -3 mol/L浓度范围内呈良好的线性关系 ;方法的检出限分别为 1× 10 -6mol/L和 5× 10 -7mol/L。由于抗坏血酸 (AA)在MWNT修饰电极上的氧化是不可逆的 ,因此利用还原峰进行测定 ,消除了AA对DA和EP的干扰     

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.     

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.     

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.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

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.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

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.     

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.