用流动注射流技术—动力学法同时光度测定铁（Ⅱ）和铁（Ⅲ）

在ＰＨ５．６的ＨＡｃＮＡｃ缓冲介质中，钛铁度剂与ＦｅⅢ）立好显色而不与Ｆｅ（Ⅱ）反应，但ｔｉｒｏｎ的存在能加速Ｆｅ（Ⅱ）的氧化进而生成有色络合物。利用不同价态Ｆｅ与ｔｉｒｏｎ反应速度的差异，可以实现Ｆｅ（Ⅱ）和Ｆｅ（Ⅲ）的动力学同时测定。本文用流动注射停流技术研究了此反应的动力学行为、估算Ｆｅ（Ⅲ）反应的条件速率常数，并对络合物的吸收光谱、反应酸度、试剂加入量、流路参数及停留时间和反应动力学特性条     

流动注射吸光光度法测定饲料样品中钙

基于钙色素（Ｃａｃｉｃｈｒｏｍｅ）在碱性条件与钙形成灵敏的红色络合物这一显色反应，在ＦＩＡ－２４００型流动注射仪上，用吸光光度计做检测器，建立了测定饲料样品中钙的流动注射吸光光度法，分析测定条件为０．２０ｍｏｌ．Ｌ＾－１氢氧化钠－０．２ｇ．Ｌ＾－１钙色素溶液为显色剂，以３０ｇ．Ｌ＾－１三乙醇胺溶液为载流，测定波长为５１０ｎｍ，钙的浓度在０～１０．０μｇ，．ｍｌ＾－１有良好线性关系，适用于测定各种饲     

离子选择电极流动注射分析同时测定钾和氯

1　引　　言在土壤、饲料、生物组织液分析中 ,钾和氯的测定非常普遍 ,人们常用光度分析、ＩＳＥ电位分析。烟草中的钾和氯含量影响其燃烧性能 ,与焦油量直接相关 ,是烟草成份的必检项目。研究一种快速、自动的分析方法很有意义。作为一种动态测量和检测技术 ,ＦＩＡ已多用于物质含量的检测和过程参数的测量 ,ＩＳＥ ＦＩＡ测定单个离子的含量亦有报道。本实验成功地实现了钾和氯离子的ＩＳＥ ＦＩＡ同时测定 ,方法简单快速。2　原　　理采用两支不同体积的进样管向流路中分别载入ＫＣｌ标准溶液 (Ｃ0 ) ,由于进样体积的差异导致标准溶液具…     

间接原子吸收法测定饮料蔬果中维生素C

利用三价铁可被维生素C还原为二价铁,铁氰化钾可与Fe2+反应生成腺氏蓝沉淀的原理,建立了原子吸收法间接测定维生素C含量的方法.实验中考察了温度、时间、氧化剂及沉淀剂用量、酸性介质对反应的影响,选取反应在室温下进行,离心时间为5min,浓度为1.0 mg/mL的Fe3+和铁氰化钾溶液各1.00mL,酸性介质为pH=3.5...     

流动注射—双显色剂双波长分光光度法同时测定铝与铁

本文将流动注射与双波长双光束分光光度计联用，选择铬天菁Ｓ和亚硝基Ｒ盐双显色剂使ＡＩ（Ⅲ）和Ｆｅ（Ⅱ）同时显色。建立了同时测定铝、铁的流动注射－双波长等吸收法。方法用于岩矿样品中铝、铁的测定，结果满意。     

痕量磷酸盐的快速流动注射分析

１引言 用碱性离子染料．杂多酸多元离子缔合物体系列测磷的灵敏度高,如用结晶紫、甲基紫、孔雀绿等碱性阳离子染料同磷钼杂多酸生成高灵敏度的多元络合物,该体系可在水相直接显色测定磷。在乳化剂ＯＰ存在下,可将这一体系应用于流动注射分析（ＦＩＡ）。传统方法中,ＰＯ４３－的ＦＩＡ测定至少需３个通道。本文以乙基紫．钼酸铵体系、双通道流路实现了ＰＯ４３－的快速分析。方法构思新颖,精密度好,既可满足检测限的要求,又大大降低仪器装置的繁杂性,节省试剂,使操作更简便,而且利于在线分析。２原理 首先使磷酸根与钼酸按反应生…     

氯化四唑蓝比色法测定微量2-脱氧-D-葡萄糖

氯化四唑蓝是还原糖的灵敏试剂,可在加热的碱性溶液中与还原糖反应,生成不溶性的三苯福尔马散红色沉淀。2-脱氧D-葡萄糖虽也属还原糖,但还原性显著减弱。我们试用四唑蓝比色法对2-脱氧-D-葡萄糖进行了微量测定。改进了操作步骤,提高了灵敏度,而且数据稳定,重现性好。 (一)试剂     

铁氰化钾-三氯化铁光度法测定蔬菜中还原糖含量

于氢氧化钠碱性溶液中,铁氰化钾试剂与样品溶液中的还原糖反应(在沸水浴中加热10min),定量生成亚铁氰化钾,此溶液冷却至室温,并用0.1mol.L-1盐酸溶液酸化至pH 3.5～4.0后随即加入三氯化铁溶液,经5min后生成普鲁士蓝。在波长680nm处用1cm吸收皿对试剂空白测定其吸光度,还原糖的质量浓度在0.8～4.0mg.L-1范围内与吸光度呈线性关系,其摩尔吸光率为3.4×104L.mol-1.cm-1。应用此方法测定了3种蔬菜样品中的还原糖含量,所得测定值与兰-埃农法测得值相符。测定值的相对标准偏差(n=5)均小于2.5%,回收试验所测得回收率在99.7%～100.1%之间。     

流动注射分光光度法测定矿物浸提液中的游离氰化物

在氢氧化钠介质中游离的氰化物与苦味酸钠反应生成玫瑰红酸钠，并进行升温改善反应条件。双流路系统与单流路相比，峰形规范、光滑，能有效消除鬼峰，优化了显色条件，工作波长为５１０ｎｍ。按生产工艺要求的线性范围为４．０￣４０．０ｍｍｏｌ／Ｌ。进样频率为１３０次／ｈ。已成功地用于矿物浸提液中游离氰化物的现场分析。     

铁氰化钾-铁(Ш)分光光度法测定药物中卡托普利

建立了K3[(Fe(CN)6]-Fe(Ш)分光光度法测定卡托普利的新方法。结果表明,卡托普利分子中的巯基(-SH)可将Fe(III)还原为Fe(II),还原生成的Fe(II)与K3[Fe(CN)6]反应生成可溶性普鲁士蓝KFe[Fe(CN)6],通过测定可溶性普鲁士蓝的吸光度,从而间接测定卡托普利的含量。显色体系的最大吸收波长为710 nm,卡托普利在2.12～19.1μg/mL范围内与吸光度A呈良好的线性关系,线性回归方程为A=0.0087+0.0276ρ(μg/mL),线性相关系数r=0.9993。方法用于实际药品中卡托普利的含量测定,结果与药典法一致。     

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。     

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.     

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。     

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.     

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。     

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.     

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.