Fe(Ⅲ)-KIO4-苋菜红体系催化动力学单扫描示波极谱法测定痕量铁

研究了在H2SO4介质中,痕量Fe(Ⅲ)催化KIO4氧化苋菜红的褪色反应.提出了催化动力学单扫描示波极谱法测定痕量铁的新方法.在1.6×10-3mol/L H2SO4介质中,苋菜红在汞电极上产生1个还原峰,峰电位为-0.186 V(vs.SCE)左右.氧化剂KIO4存在时,在-0.186 V处的峰电流的降低与加入Fe(Ⅲ)离子在0～0.04μg/mL范围内呈良好的线性关系,检出限4.2×10-9g/mL.同时研究了该方法适宜的反应条件,应用本方法测定中草药和水中铁的含量,回收率在98%～101%之间,结果满意.     

偶合反应流动注射化学发光法测定镓

基于Ga(Ⅲ )置换Fe EDTA络合物中Fe 和Fe Luminol O2 产生化学发光的反应 ,建立了置换偶合反应流动注射化学发光测定痕量镓的新方法。方法线性范围为 1.4× 10 - 7～ 1.4× 10 - 5g mL ;检出限为 3×10 - 8g mL ;对 5× 10 - 6 g mL镓标准溶液进行 11次平行测定 ,相对标准偏差为 2 .6 %。方法用于中草药中痕量镓的测定 ,结果满意     

酸性大红褪色光度法测定痕量铜

研究了在氨 氯化铵介质中铜催化过氧化氢氧化酸性大红的褪色反应及其动力学条件,测定了反应级数和表观活化能,建立了测定痕量铜的新方法。该方法的检出限为6.1×10-3μg/mL,线性范围为0～4.0μg/25mLCu,用于测定水中痕量Cu,结果与原子吸收法的测定结果一致。     

铜(Ⅱ)-铬天青S-过氧化氢体系催化光度法测定痕量铜

本文研究了在氨水介质中,痕量铜对过氧化氢氧化铬天青S褪色反应的催化作用,建立了一个催化光度法测定痕量铜的新方法。线性范围为0～20ng/mL,检出限为5.59×10~(-11)g/mL,并用于铝合金标准样品,环境标准样品和自来水中痕量铜的测定。     

铑(Ⅲ)与5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯的极谱催化氢波研究

本文研究了铑( )与5-(5-硝基-2-吡啶偶氮)-2,4-二氨基甲苯(5-NO2-PADAT)配合物的极谱行为,发现在pH=5.00HAc-NaAc缓冲溶液中,配合物于-1.20V(vs.SCE)处产生一灵敏的极谱催化氢波。基于此,建立了测定痕量铑的新方法。该催化氢波峰电流i′p与铑( )浓度在2.0×10-3～1.8×10-2μg/mL范围内呈线性关系,检出限为1.0×10-3μg/mL。研究了该催化氢波的性质及其反应机理。     

化学发光法测定I-的研究

研究了高锰酸钾-Ⅰ--甲醛体系化学发光,从而建立了一种测定微量Ⅰ-的新方法.讨论了各种反应物浓度、酸度、干扰离子等因素对测定结果的影响.Ⅰ-浓度在1.0×10-6～4.0×10-5g/mL范围内与化学发光强度有较好的线性关系.对1.0×10-5g/mL的Ⅰ-进行了11次平行测定,相对标准偏差为2.8%,方法的检出限为2.4×10-8g/mL.结果令人满意.     

无机偶合流动注射化学发光测定钛的研究

基于钛(Ⅲ)对铬(Ⅵ)氧化I-产生I2的诱导作用,和I2氧化鲁米诺产生化学发光的反应,建立了无机偶合反应流动注射化学发光测定痕量钛的新方法。方法线性范围为1×10-9～1×10-5g/mL,RSD=3.0%(n=11,ρ=1×10-7g/mL),检出限为4.0×10-10g/mL。方法用于人发样品中钛的测定。     

基于偶联反应新极谱法测定痕量亚硝酸根的研究——Ⅱ.以苯酚为偶联试剂

本文研究了苯酚在氨性缓冲溶液中与NO_2~--磺胺重氮盐偶联反应的实验条件,建立了一个灵敏快速测定痕量NO_2~-的新方法。NO_2~-离子浓度在1.0×10~(-10)～4.8×10~(-7)g/ml范围内,与峰高呈良好的线性关系.4000倍量NO_3~-存在不干扰.     

罗丹明B-过氧乙酸-氢氧化钠化学发光法测定痕量硫

基于硫离子对罗丹明B 过氧乙酸 NaOH化学发光有较强的增敏作用,建立了流动注射化学发光增强法测定痕量硫的新方法。该法的线性范围为3.0×10-8～8.0×10-7g/mL,检出限为3.5ng/mL,相对标准偏差为2.2%(1.0×10-7g/mLS2-,n=11)。此法已用于环境水样中痕量硫的测定。     

铜(Ⅱ)催化铍试剂Ⅲ还原反应的动力学及其应用

在2,2'-联吡啶的存在下,铜(Ⅱ)催化抗坏血酸还原铍试剂Ⅲ的反应.考察了影响反应的条件,讨论了反应机理,建立了测定超痕量铜的新方法.方法的检出限是1.27×10-11g/mL,测定范围是0.00～1.00ng/mL.本法已用于自来水和矿泉水中痕量铜(Ⅱ)的测定.     

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.     

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。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

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.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。