同步荧光光谱法测定蛋白质

在模拟生理条件下,由于核苷类药物中间体氰基乙基尿嘧啶(CEU)与血清白蛋白相互作用,血清白蛋白的内源荧光发生特异性变化,且体系的同步荧光强度和溶液中血清白蛋白的浓度呈线性关系,据此提出以氰基乙基尿嘧啶为探针,用固定波长同步荧光光谱法测定人血清白蛋白(HSA)和牛血清白蛋白(BSA)的方法.在最佳试验条件下,体系的荧光强度与HSA和BSA的质量浓度分别在1.38～496.2 mg·L-1和1.56～624.0 mg·L-1范围内呈线性关系,检出限(3S/N)分别为0.045 mg·L-1和0.051 mg·L-1.方法应用于人血清及牛血清中HSA及BSA的测定,并以此样品为基体分别加入HSA及BSA标准溶液作回收试验,测得回收率在95.1%～102.5%之间,相对标准偏差(n=6)在0.43%～2.72%之间.     

顶空-气相色谱-质谱法测定水中氯代苯胺类化合物

提出用顶空采样法富集水样中12种氯代苯胺类化合物,经气相色谱分离后用质谱法测定其含量。试验选择了最佳顶空条件。取水样8.00mL置于顶空瓶中,加入碳酸钠3.4g(盐析剂)和0.500mg·L-1内标溶液8μL,于80℃恒温条件下振荡40min。测定的12种化合物以气体状态进入DB-35MS色谱柱,按程序升温模式进行分离;质谱测定中,采用电子轰击离子源和选择离子监测模式。12种氯代苯胺类化合物的质量浓度在一定范围内与其峰面积呈线性关系,其检出限(3.14s)在0.03～0.3μg·L-1之间。按标准加入法进行回收试验,测得回收率在86.0%～131%之间,测定值的相对标准偏差(n=6)在3.0%～20%之间。     

顶空气相色谱法测定羧甲基壳聚糖中氯乙酸残留量

采用顶空气相色谱法间接测定了羧甲基壳聚糖中氯乙酸的残留量。样品(0.2g)于顶空瓶中超声溶解在水3mL中,加入甲醇2.5mL,硫酸1.5mL,在70℃水浴反应40min使之酯化。按顶空条件进样,用HP-INNOWAX毛细管色谱柱分离,氢火焰离子化检测器测定。分别选择15min和85℃作为样品在顶空瓶中的平衡时间和平衡温度。氯乙酸的质量在0.2～20mg范围内与其峰面积呈线性关系,方法的检出限(3S/N)为5.6mg·L-1。方法用于实样中氯乙酸的测定,用标准加入法做回收试验,测得回收率在90.0%～92.0%之间,测定值的相对标准偏差(n=5)在0.7%～0.9%之间。     

锌-镉还原-分光光度法测定地表水中硝酸盐

提出预先将试样中NO-3用锌-镉还原法还原为NO-2.对还原反应的条件,诸如氯化钠及氯化镉的浓度、溶液的PH值、金属锌(卷状)的加入量以及还原反应所需时间等,进行了研究和优化.还原所得NO-2在酸性溶液中与磺胺进行重氮化后再与萘乙二胺偶合生成红色偶氮化合物.在其吸收峰543 nm波长处测定其吸光度,据此,在校正曲线上间接地查得试样中NO-3的含量.NO-3质量浓度在0～0.400 mg·L-1范围内遵守比耳定律.方法的检出限(S/N=3)为0.008 mg·L-1,在0.1 mg·L-1的浓度水平进行了测定的精密度试验,计算得到相对标准偏差(n=6)为2.1%.在3个浓度水平上作了回收试验,得出回收率在99%～103%之间.     

顶空-气相色谱法测定伊班膦酸钠注射液中丙酮和乙醇残留量

采用顶空-气相色谱法测定伊班膦酸钠注射液中丙酮和乙醇的残留量。选择顶空平衡温度和时间分别为70℃和40min,用CP-WAX毛细管色谱柱(30m×0.25mm,0.25μm)分离,氢火焰离子化检测器检测。丙酮的质量浓度在0.05~120mg·L-1范围内与其峰面积呈线性关系,检出限(3S/N)为0.015mg·L-1。乙醇的质量浓度在0.25~120mg·L-1范围内与其峰面积呈线性关系,检出限(3S/N)为0.25mg·L-1。丙酮和乙醇的加标回收率分别在97.0%~112%和94.9%~112%之间。丙酮和乙醇的峰面积相对标准偏差(n=6)分别为2.2%和2.5%。     

气相色谱法测定果蔬中防腐剂仲丁胺残留量

提出了气相色谱法测定果蔬中防腐剂仲丁胺残留量的方法。果蔬样品经匀浆处理后置于顶空瓶中,在碱性条件下于55℃恒温平衡40min。吸取100μL液上气体注入气相色谱仪,用氮磷检测器测定,外标法定量。仲丁胺的质量浓度在0.000 5～0.040 0mg.L-1范围内与其峰面积呈线性关系,检出限(3S/N)为0.5μg.L-1。在两个浓度水平上对方法进行回收试验,测得回收率在87.4%～102.8%之间,测定值的相对标准偏差(n=10)在2.6%～9.6%之间。     

电堆集-非水毛细管电泳分离测定甘草次酸和阿魏酸的研究

建立了电堆集富集-非水毛细管电泳(NACE)同时分离测定甘草中甘草酸和阿魏酸的新方法.系统研究了电压、非水溶剂、乙酸钠浓度、氢氧化钠浓度、样品溶剂等因素对电堆集和分离效果的影响,确立了分离和富集的最佳条件.以甲醇-乙腈(体积比4 : 6)为非水介质,30 mmol·L-1乙酸钠-2.5 mmol·L-1氢氧化钠为背景电解质;分离电压-20 kV,检测波长254 nm.在优化条件下,甘草次酸在0.80 ～12.80 mg·L-1(r＝0.999 6),阿魏酸在0.77 ～45.60 mg·L-1(r＝0.999 6)质量浓度范围内线性关系良好,回收率分别为97% ～102%,98% ～102%;甘草次酸检出限为0.069 mg·L-1,阿魏酸检出限为0.087 mg·L-1,RSD均不大于4.6%.     

顶空-气相色谱法测定止血微球中环氧氯丙烷残留量北大核心CSCD

将0.15 g止血微球粉末样品和5.00 mL水置于20 mL顶空瓶中,立即密封顶空瓶,在顶空平衡温度为80℃,平衡时间为30 min的条件下进行顶空采样.以DB-5毛细管柱为固定相,采用电子俘获检测器(ECD),用气相色谱法测定其中环氧氯丙烷残留量.结果表明,环氧氯丙烷的质量浓度在0.02~2.0 mg·L^(-1)内与其峰面积呈线性关系,测定下限(10S/N)为0.005 mg·L^(-1).按标准加入法进行回收试验,回收率为95.3%~101%,测定值的相对标准偏差(n=6)小于7.0%.     

流动注射-化学发光法测定苄青霉素

试验发现在5×10-3mol·L-1氢氧化钠溶液的碱性介质中,由高碘酸钾与鲁米诺之间的氧化还原反应所产生的化学发光的强度因苄青霉素的存在而明显增强,且其增强程度与苄青霉素的浓度在0.01～15.0 mg·L-1范围内呈线性,方法的检出限(3σ)为1.0μg·L-1,基于此并应用了流动注射技术,提出了一种简便而快速的测定苄青霉素的方法.加入1.0 mg·L-1的苄青霉素标准溶液对此方法的精密度做了试验,测得其相对标准偏差(n=11)为1.0%.在3件针剂样品的基础上加入了3种不同浓度的苄青霉素标准溶液,对方法的回收率做了试验,所得结果在97.2%～102.0%之间.     

气相色谱法测定牙膏中二甘醇的含量

牙膏样品中的二甘醇用甲醇与水(4+1)的混合溶剂提取,用离心法分相后取上层清液进行气相色谱分析,对色谱测定的条件进行了试验并予以优化.测定中采用DB-FFAP色谱柱作分离,并采用氢火焰离子化检测器进行测定.结果表明:二甘醇质量浓度在5.0～500.0 mg·L-1范围内对相应的检测信号(峰面积)之间呈线性关系.方法的检出限(3S/N)为2.5 mg·L-1,在3种不同浓度水平条件下对方法的回收率及精密度进行了试验,测得回收率在96.5%～97.2%之间,测定值的相对标准偏差(n=7)在1.7%～2.1%之间.     

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.     

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。     

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。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...     

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.     

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.     

Synthesis of tetrabenzoporphins of the basis of isoindoline

Chemistry of Heterocyclic Compounds -