新催化动力学光度法测定微量铁的研究--棓花青-O2指示反应体系

在 p H 7.0的磷酸盐缓冲体系中 ,微量铁 ( )能显著催化溶解氧氧化木立口 花青褪色。研究了该指示反应的催化动力学行为 ,建立了测定微量铁的新催化动力学分析法 ,方法线性测定范围 0 .0 5～ 0 .6μg· m L- 1 ,检出限为 0 .0 1 μg· m L- 1 。本法选择性和重现性好 ,反应体系简单易于控制。用其测定了自来水、人发及面粉等样品中的铁 ,结果满意。     

铝电解质中二氧化锡的光谱测定

本文探讨了发射光谱法测定铝电解质中二氧化锡。粉末试样不需溶样，人工合成标准系列，消除了组织结构对测定的影响，对缓冲剂、内标、电极形状及摄谱条件作了最佳选择，ＲＳＤ为５．９％，加标回收率为１００．９％，与国外ＸＲＦ结果十分吻合。     

Intramolecular Alkylation of Aromatic Compounds XXXVI [1]. Stereoselective Synthesis of C/D-cis-Configured Ergolines

Summary.  The stereoselective synthesis of cis-ergoline is presented. Starting from rac-N-benzoyl tryptophan methyl ester, the key compound indolinylmethylpyridin-3-one was prepared via a seven-step reaction in good yield. Since its cyclization to the desired ergolinone failed, the key compound was reduced to yield the two diastereomeric pyridin-3-ols; only one of them cyclized in trifluoromethanesulfonic acid, affording cis-ergoline. Catalytic hydrogenation of the latter gave N,N′-dimethyldihydroergoline, the X-ray crystallography of which revealed both the correct structure and identical relative configurations at C-5a and C-6a (SS or RR). Hydroboration and subsequent perruthenate oxidation of the Δ⁹-ergoline provided access to the regioisomeric ergolinols and ergolinones. Received December 27, 2001. Accepted January 15, 2002     

Measurement of the adduction constant by gas-liquid chromatography

Summary The adduction constants for the following eight binary systems were measured by gas liquid chromatography, at different temperatures: tetrachloromethane/p-xylene, tetrachloromethane/pseudocumene, chloroform/p-xylene, chloroform/pseudocumene, chloroform/aniline, m-methylphenol/aniline, o-methylphenol/aniline, and o-chlorophenol/aniline. The relationships between the adduction constant and temperature were used to fit the enthalpies and entropies of adduct formation.     

High-performance liquid chromatographic determination of glaucine inGlaucium flavum crantz

Summary A method has been developed for the extraction and rapid analysis of D-glaucine inGlaucium flavum Crantz. Simple extraction of the drug with diethyl ether was followed by high-performance liquid chromatography on a μBondapak C₁₈ column using a mixture of acetonitrile, methanol and phosphate buffer as the mobile phase. Data on selectivity, sensitivity and precision demonstrate the reliability of this method.     

Determination of ppt levels of atmospheric volatile organic compounds in Yakushima, a remote south-west island of Japan

An analytical method was utilized to detect ppt levels of VOCs in air. The method was based on the US-EPA method TO-14, consisting of canister sampling, three module enrichment and GC/MS analysis. Target compounds included chlorofluorocarbons (four kinds), benzene and its derivatives (14), halogenated hydrocarbons (20), and others (three). The minimum detection limits of the method for the target compounds ranged from 0.016 to 0.040 ppb (0.06–0.23 μg/m³). The recoveries of the target compounds ranged from 77 to 113% and relative coefficients of variation (n=4) were 3.0–9.0%. The sampled air was stable for at least 14 days after pressurizing with humidified nitrogen gas at 200 kPa (absolute pressure). The method was applied to analyze the VOCs in the air of Yakushima, a remote island of south-west Japan where no distinct local pollution source is considered.     

辣根过氧化氢酶电极的研究

以辣根过氧化氢酶修饰电极采用循环伏安法对环境污染物对对苯二酚进行了测定 ,对测定条件进行了探索 ,该电极在 p H7,H2 O2 浓度为 1 0μmol· L-1时对苯二酚具有良好的响应 ,其线性范围为 2 .0× 1 0 -5～ 2 .8× 1 0 -3mol·L-1,检测下限为 1 .0× 1 0 -6mol· L-1。电极的峰电流与扫描速度的平方根成正比 ,电极上的传质过程受扩散控制 ,对酶催化反应的动力学机制进行了探讨。     

探针体耐尔蓝(NB)与DNA结合反应研究

应用微相吸附-光谱修正（MPASC）新技术研究DNA与耐尔蓝（NB）探针分子间的相互作用,分析生物大分子内静电场的形成与Langmuri吸附的关联性,测定了结合产物结合比、平衡常数等。通过在pH=10.38介质中对DNA-NB反应的光谱分析,结果表明产物结合比NB：DNA-P=3：1、平衡常数K=3.33×10^5,摩尔吸收系数ε^660nm=4.81×10^3L/mol cm。样品分析表明DNA回收率95.6%-108%,相对标准偏差RSD=2.8%。     

油脂中九种抗氧化剂的反相高效液相色谱法分离和测定

研究了油脂中９种酚类抗氧化剂的色谱保留行为,以甲醇－水－乙酸体系为流动相,采用梯度洗脱,可在３０ｍｉｎ内将九种物质完全分离并定量测定。测定的线性范围１￣２００ｍｇ／ｌ（ｒ＝０．９９８５￣０．９９９７）,检测限为２ｍｇ／ｋｇ,回收率为８２．４％￣９８．７％,ＲＳＤ为１．０１％￣４．７４％。     

Spectrophotometric Determination of Trace Amounts of Vanadium Based on its Catalytic Effect on the Reaction of Diphenylamine and Hydrogen Peroxide

 In this work a kinetic spectrophotometric method for the determination of trace amounts of vanadium is presented. The method is based on the catalytic effect of the vanadium(V) on the reaction between diphenylamine (DPhA) and hydrogen peroxide in a concentrated solution of formic acid. The formation of the deep-blue oxidation product is followed by a filter spectrophotometer, equipped with an optical fiber assembly, on line with a PC provided with the suitable software. The measurements were taken at 583 nm, with an immersed type cell of 1 cm light path length. The optimization of the operating conditions regarding concentrations of the reagents, temperature and interferences are also investigated. The working curve is linear over the concentration range 0.40–4.0 μg/ml vanadium(V). The relative standard deviation for a standard solution of 0.6 μg/ml of vanadium is 0.5% (n = 5). The proposed method proved highly sensitive, selective and relatively rapid for the assay of vanadium, at low level of 0.40 μg/ml without any pre-concentration step. The method was applied to alloys and cosmetics samples. The results were compared to those received with a reference method. Good agreement was attained, with a mean error of 0.5%. Received February 25, 2000. Revision May 15, 2000.