流动注射化学发光法测定间苯二酚

在碱性条件下,铁氰化钾氧化鲁米诺产生化学发光,间苯二酚对这一体系的化学发光具有很强的抑制作用.据此,结合流动注射技术,建立了一种测定间苯二酚的方法.线性范围为1.0×10-7～1.0×10-5mol·L-1;检出限(3σ)为2.0×10-8mol·L-1.该方法用于环境水样和皮炎宁酊中间苯二酚的测定,测定值的相对标准偏差(n=7)在1.9%～2.1%之间,其回收率在98.8%～103.0%之间.     

唑类有机化合物修饰电极同时测定尿液中的多巴胺和黄嘌呤

建立以唑类有机化合物(4-氨基-4H-1,2,4,-三唑)修饰玻璃电极,得到聚唑类有机合物膜修饰电极,并以该电极对多巴胺(DA)和黄嘌呤(XN)进行同时分析测定。结果表明,在0.2 mol·L-1的磷酸盐缓冲液(p H=5.0)中,DA和XN在聚唑类有机化合物修饰的电极上具有比较好的电化学行为。多巴胺和黄嘌呤分别5×10-5~5×10-9mol·L-1和1×10-4~1×10-7mol·L-1浓度范围内有较好的电化学响应,DA和XN检出限分别为5×10-10mol·L-1和1×10-8mol·L-1,该修饰电极具有较高的灵敏度、重现性和稳定性。该方法可用于人体的尿液中两种化合物的同时测定分析,回收率分别为94.7%~99.3%与93.6%~95.3%.     

水中痕量土霉素的亲水溶剂浮选-分光光度测定

本文利用自制的浮选装置,选择四氢呋喃和无水乙醇(4+1)混合溶液作溶剂,氯化钠作分相剂,将Fe(Ⅲ)与土霉素(OTC)形成的疏水性缔合物浮选至有机相,然后采用分光光度法测定,方法线性线性范围为6.6×10~(-7)～3.4×10~(-5) mol/L;检出限为3.63×10~(-7) mol/L;平均回收率为99.95%;表观摩尔吸光系数ε=2.028×10~5 L·5moL~(-1)·5cm~(-1).该方法设备简单、测定快速、灵敏度高、分离物质易于提取和不产生二次污染,可用于环境水样中痕量土霉素的快速测定.     

三联吡啶合亚钌-亚硫酸根-氯酸钾体系化学发光法测定白葡萄酒中总亚硫酸盐

试验发现,亚硫酸根与氯酸钾及Ru(Ⅱ)与α,α'-联吡啶的络合物,Ru(Bipy)32 在SDBS存在下反应所产生的化学发光强度与亚硫酸根的浓度在1.0×10-7～1.0×10-4mol·L-1范围内呈线性关系,其检出限(3S/N)为9.26×10-8mol·L-1,对浓度为1.0×10-4mol.L-1亚硫酸根溶液重复6次测定,相对标准偏差为3.2%.该方法测定白葡萄酒中的总亚硫酸盐含量为3.384×10-5mol·L-1.并以此为基体加入3种不同浓度的亚硫酸根标准溶液作回收试验,测得回收率在96.8%～102.2%之间.     

邻苯二酚在多壁碳纳米管修饰玻碳电极上的电化学行为及其测定

叙述了多壁碳纳米管修饰玻碳电极的制备方法,多壁碳纳米管用前需经硫酸-硝酸(3+1)混合酸预处理以增强其反应活性.与裸玻碳电极相比,多壁碳纳米管修饰电极具有更高的氧化还原峰电流和更低的氧化电位.试验优化了支持电解质、pH值、扫描速率等测定条件,此法测定邻苯二酚的线性范围为4.0×10-7～8.0×10-5mol·L-1,检出限(3S/N)为6.0×10-8mol·L-1.应用于模拟水样中邻苯二酚的测定.在4个浓度水平上用标准加入法作了回收试验,测得其回收率在99.2%～103.0%之间,相对标准偏差(n=8)均小于3.5%.     

直接电化学方法制备石墨烯修饰电极及对肼的检测

采用循环伏安法制备了石墨烯修饰玻碳电极并对其进行表征。研究了肼在石墨烯修饰玻碳电极上的电化学行为。结果表明:石墨烯修饰电极对肼有良好的电催化活性,在BR缓冲溶液(pH 7.0)中动态安培法检测肼的线性范围分别为1.0×10-8～4.4×10-7mol.L-1和4.4×10-7～1.3×10-4mol·L-1,检出限(3sb)为9.9×10-9mol·L-1,利用该方法测定了模拟水样中肼的含量,平均加标回收率为100%。     

银(Ⅲ)配合物-鲁米诺体系流动注射法测定醋酸泼尼松

在碱性环境下,银(Ⅲ)配合物可与鲁米诺产生化学发光,醋酸泼尼松对该发光体系具有显著的增敏作用,据此提出了流动注射银(Ⅲ)配合物-鲁米诺化学发光体系测定醋酸泼尼松含量的方法。优化的试验条件如下:1鲁米诺溶液中氢氧化钠的浓度为0.6mol·L-1;2鲁米诺溶液的浓度为8.0×10-7 mol·L-1;3银(Ⅲ)配合物溶液中氢氧化钠的浓度为1.7mol·L-1;4银(Ⅲ)配合物溶液的浓度为5.0×10-5 mol·L-1。醋酸泼尼松的线性范围为6.0×10-8~8.0×10-5 mol·L-1,方法的检出限(3s/k)为2.9×10-9 mol·L-1。对1.0×10-6 mol·L-1醋酸泼尼松标准溶液连续测定11次,测定值的相对标准偏差为2.9%。加标回收率在100%~105%之间。     

利用对三溴偶氮胂-锆（Ⅳ）络合物的置换反应光度法测定草酸

在0.20 mol.L-1盐酸介质中,锆(Ⅳ)与三溴偶氮胂形成1:1蓝紫色络合物,加入草酸可置换络合物中的三溴偶氮胂,使显色溶液的吸光度升高,草酸的浓度与吸光度升高值成正比.在506 nm波长处,草酸浓度在1.0×10-4～6.5×10-4mol.L-1范围内遵守比耳定律.方法的表观摩尔吸光率ε506nm:1.23×10.L·mol-1·cm-1,检出限为0.074 mg·L-1.方法已直接用于地下水以及西红柿样品中草酸含量的测定,所得结果与文献[7]的方法结果相符.测定值的相对标准偏差(n=13)均小于2%,所测得的回收率在95.7%～103.9%之间.     

流动注射-鲁米诺-铁氰化钾反应体系化学发光法测定依诺沙星

试验发现依诺沙星对鲁米诺与铁氰化钾之间的化学发光反应具有显著的增敏作用,而且当依诺沙星浓度在2.0×10-8～2.0×10-5mol·L-1范围内,与相应的化学发光增强信号值(△I)之间呈线性关系,其检出限(3S)为5.7×10-9mol·L-1,取1.0 × 10-6mol·L-1依诺沙星按试验方法测定11次,算得其相对标准偏差为1.75%.结合应用流动注射技术,提出了流动注射-化学发光法(FI-CL)测定药片中依诺沙星的方法,应用此方法分析了3个依诺沙星片剂试样,所测得的结果与其标示值相符.按标准加入法作了回收率试验,所得结果在96.7%～103.0%之间.     

盐酸吡格列酮-乙基曙红荷移光度测定法

在pH 4.0的盐酸-乙酸钠缓冲介质中,吡格列酮(PGTZ)与乙基曙红(EE)之间发生荷移反应,形成离子缔合物,使溶液发生褪色现象,且在516 nm波长处测定时,溶液的褪色程度与盐酸吡格列酮的浓度在9.75 × 10-7～1.26×10-5mol·L-1范围内呈线性关系.表观摩尔吸光率(ε516)为6.44×104·mol-1·cm-1,检出限(3s/k)为3.25×10-7mol·L-1.方法用于市售药品中PGTZ含量的测定,所得结果与标示值及高效液相色谱法(HPLC)测得结果相符.以血浆及尿液样品为基体加入标准溶液作回收试验,测得其回收率在97.7%～103.3%之间,测定值的相对标准偏差(n=6)均小于2.5%.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.