简易型离子选择电极-流动注射分析仪的研制及卤水中氯、溴和碘的连续测定

本文设计研制了简单实用的流通池,组装了简易型离子选择电极—流动注射分析仪,对体系的分析特点和影响因素进行了考察。此装置性能可靠,能满足简单流注分析的需要,并建立了卤水中Cl~-、Br~-和I~-的连续测定方法。     

H-NMR studies of duplex DNA decamer containing a uracil cyclobutane dimer: implications regarding the high UV mutagenecity of CC photolesions

To determine the origin of the UV-specific CC to TT tandem mutation at the CC site, we made a duplex DNA decamer containing a uracil cis-syn cyclobutane dimer (CBD) as the deaminated model of a cytosine dimer. Two-dimensional 1H-NMR spectroscopy studies were performed on this sequence where two adenines (Ade) were opposite to the uracil dimer. Two imino protons of the uracil dimer were found to retain Watson-Crick hydrogen bonding with the opposite Ade, although the 5'-U(NH) of the dimer site showed unusual upfield shift like that of the 5'-T(NH) of the TT dimer, which seemed to be associated with deshielding by the flanking base rather than with reduced hydrogen bonding. (McAteer et al. 1998, J. Mol. Biol. 282:1013-1032). Hydrogen bondings at the dimer site were also supported by detecting typical strong nuclear Overhauser effects (NOE) between two imino protons and the opposite Ade H2 or NH2. But sequential NOE interactions of base protons with sugar protons were absent at the two flanking nucleotides of the 5' side of the uracil dimer and at the intradimer site, contrasting with its thymine analog where sequential NOE was absent only at the A4-T5 step. In addition, NOE cross peak for U5(NH) <--> A4(H2) was detected, although the NOE interactions of U6(NH) with A7(H2) and A17(H2) were not observed in contrast to the thymine dimer duplex. This different local structural alteration may be affected by the induced right-hand twisted puckering mode of cis-syn cyclobutane ring of the uracil dimer in the B-DNA duplex, even though the isolated uracil dimer had left-hand twisted puckering rigidly. In parallel, these observations may be correlated with observed differences in mutagenic properties between cis-syn UU dimer and cis-syn TT dimer.     

催化动力学极谱法测定痕量钼

在稀Ｈ２ＳＯ４介质中，钼（Ⅵ）对硫酸联氨还原乙基橙的反应有强烈的催化作用。建立了催化动力学极谱法测定痕量钼的新体系，方法线性范围为２０－３００ｎｇ／ｍＬ，检出限为３．５４ｎｇ／ｍＬ。方法应用于尿中中钼的测定，结果满意。     

Preparation of Europium Induced Conformation—specific anti—calmodulin Monoclonal Antibody

Monoclonal antibody technique was employed to detect the conformational difference of CaM induced by metal ions. A trivalent europium ion induced conformation-specific anti-calmodulin monoclonal antibody was successfully prepared with europium-saturated calmodulin as antigen.     

Application of microemulsions in determination of chromium naphthenate in gasoline by flame atomic absorption spectroscopy

A new method using microemulsified samples is presented. It is for the determination of chromium naphthenate in gasoline by flame absorption spectroscopy. The method has the advantage of simplicity, speed and the use of aqueous standards for calibration instead of organic standards. Coexistent elements do not disturb the determination. Results obtained by this method were better than those obtained by other methods for the same samples.