阻抑-催化褪色动力学光度法测定食盐中的微量碘

在KH2PO4-K2HPO4介质中,微量碘(I-)对过氧化氢氧化碱性藏花红褪色反应有抑制作用,据此,建立了阻抑催化褪色动力学光度测定痕量碘的方法。该法的线性范围为0~40μg/L,检出限为1.6×10-8g/L。本法用于食盐中微量碘的测定,分析结果满意。     

测定尿中痕量碘的高锰酸钾-亚砷酸体系催化光度法

在硫酸和磷酸的介质中,碘离子催化高猛酸钾与亚砷酸反应生成的锰（Ⅲ）氧化砷酸的反应,据此建立了催化光度法测定痕量碘的新方法。该法的检出限为0．4μg/L,测定的线性范围为1．0－25．0μg/L。应用该法测定了尿样中痕量碘的含量,获得了满意的结果,测定样品的相对标准偏差（n＝6）为2．5％－3．7％,加标回收率为96．4％－102．6％。     

阻抑动力学分光光度及荧光光度法测定微量碘

在稀磷酸介质中,微量碘离子对亚硝酸根催化溴酸钾氧化吡罗红B褪色及荧光猝灭的反应有显著阻抑作用,以此为指示反应提出了测定微量碘离子的阻抑动力学光度和阻抑动力学荧光分析新方法。测定碘离子的线性范围分别为4-200μg/L和3-40μg/L,检出限分别为2.8μg/L和1.6μg/L。用于食品中微量碘的测定,结果满意。     

高效阴离子交换色谱-脉冲安培检测器测定工业醋酸中痕量碘离子的方法

用一次性银电极高效阴离子交换色谱-脉冲安培检测器(HPAEC-PAD)研究了36%HAc中痕量碘离子的测定方法。用5 mL分析纯HAc(36%,不含碘离子)配制碘离子的标准工作溶液,然后加入一定体积的质量分数为25%NaOH溶液中和HAc,待溶液冷却至室温后用Milli-Q水定容至10 mL,最后用高效阴离子交换色谱-脉冲安培检测器分离测定,得到碘离子的标准工作曲线。工业醋酸样品经同样处理步骤。方法的检出限为0.06μg/L(3倍基线噪音),定量限为0.2μg/L(10倍基线噪音)。10μg/L碘离子的加标回收率为105%,5次连续测定的相对标准偏差为3.4%。     

阻抑动力学分光光度法测定食品中痕量碘

研究了在稀硫酸介质中,痕量碘离子对亚硝酸根催化溴酸钾氧化甲酚红的阻抑作用,建立了测定痕量碘离子的阻抑动力学光度分析的新方法。测定碘离子的线性范围为0～0.62μg/mL,检出限为7.43×10-9 g/mL。已用于食品中痕量碘的测定,结果满意。     

阻抑动力学分光光度法测定痕量碘

研究了在稀H3PO4介质中,痕量碘离子对NO-2催化溴酸钾氧化吖啶橙的阻抑作用,建立了测定痕量碘离子的阻抑动力学光度分析的新方法。测定碘离子的线性范围为0～0.40μg/mL,检出限为7.3×10-9g/mL。已用于食品中的微量碘的测定。     

氢化物发生-原子荧光光谱法间接测定痕量碘的研究

提出了氢化物发生-原子荧光光谱法间接测定痕量碘的新方法,在弱酸性介质中,以Ⅰ--[Cd(Phen)3]2 -硝基苯为萃取体系,经0.24 mol/L的HCl反萃取后,用原子荧光光谱法测定镉量,从而间接测定碘.方法的线性范围为0～20 μg/L;相对标准偏差为8.5%;检出限为0.8 μg/L;回收率为74.63%～90.80%.方法已用于测定自来水中的碘量.     

电感耦合等离子体质谱法同时测定矿泉水中痕量溴和碘

建立了电感耦合等离子体质谱法(ICP-MS)同时测定矿泉水中痕量溴、碘,比较了不同酸碱度对溴、碘测定的影响。测量过程中对溴、碘的记忆效应进行消除,选择了最佳的工作条件,溴、碘的方法检出限分别为0.63,0.112μg/L,相对标准偏差分别为3.1%和1.8%,加标回收率为96%～107%。对国家标准水样进行了测定,测定结果与推荐值一致性较好。     

乙醇增强-电感耦合等离子体质谱法测定植物样品中的痕量碘

建立了氨水密封溶样法处理样品,乙醇增强灵敏度,电感耦合等离子体质谱(ICP-MS)直接测定植物样品中痕量和超痕量碘的方法。样品溶液中加入体积分数2%乙醇,同时调节载气流速和采样深度,碘响应信号可增强4倍多。碘的方法检测限可达到(10σ,DF=1000)0.005μg/g。利用建立的方法对圆白菜、菠菜2种植物标准物质中的碘含量进行了测定,测定结果均在标准值的允许误差范围之内。对西宁低碘地区植物样品中碘含量进行了分析,低碘植物样品多为植物的果实部分,碘含量均小于0.01μg/g。     

高效液相色谱-电感耦合等离子体质谱法测定土壤中不同形态的无机碘

建立了一种有效分离检测土壤中不同形态无机碘(碘离子和碘酸根离子)的高效液相色谱-电感耦合等离子体质谱法(HPLC-ICP-MS)。采用4 mmol/L四丁基氢氧化铵(TBAH)溶液为提取剂进行超声提取,经离心分层,过Na柱和0.22μm滤膜后进行分析,以50 mmol/L碳酸铵溶液(pH 9.8,以25%氨水调节)为流动相,采用AS16阴离子分析柱进行HPLC-ICP-MS测定。结果表明,在优化实验条件下,两种无机碘形态(I~-和IO~-_3)在10～500μg/L范围内线性关系良好,相关系数(r~2)均大于0.999,检出限分别为0.05、0.1μg/L,定量下限分别为2、5μg/L。该方法用于土壤环境中无机碘的测定,其加标回收率为83.8%～108%,相对标准偏差(RSD)为0.5%～3.0%,优于振荡提取法。该方法快速、高效、重现性好、灵敏度高,适用于土壤环境中不同形态无机碘的测定。     

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。     

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.     

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.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

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.     

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.