Gd2O3:Eu纳米晶的制备及其光谱性质研究

以EDTA为络合剂，聚乙二醇为有机分散剂，用络合溶胶—凝胶法制备出Gd2O3:Eu纳米晶。用XRD，SEM，X—射线能量色散谱仪(EDS)，荧光分光光度计等分析手段对Gd2O3:Eu的纳米晶结构、形貌、组分的均匀性以及发光特性进行了研究。结果表明：EDTA—M凝胶仅在800℃焙烧即可得到颗粒细小、组分均匀、纯立方相的Gd2O3:Eu纳米晶，颗粒基本呈球形，粒径为30nm左右。对样品的激发光谱、发射光谱测定表明：Gd2O3:Eu纳米晶在269nm光激发下发红光，发射光谱谱峰在611nm，与体材料基本相同；激发光谱中电荷迁移带(CTB)明显红移，从体材料的255nm移至269nm，移动了约14nm；猝灭浓度从体材料的6％提高到8％。     

流通池介质交换差示脉冲阳极溶出伏安法用于多元素重叠峰的分离及其同时测定

本文用流通池介质交换差示脉冲阳极溶出伏安法在盐酸介质中富集,而以碳酸钠-碳酸氢钠缓冲溶液为溶出介质,有效地分离了酸性介质中Cu(Ⅱ)、Sb(Ⅲ)、Pb(Ⅱ)、Tl(Ⅰ)、Cd(Ⅱ)、In(Ⅲ)的重叠溶出峰,实现了多离子的同时测定。     

离子色谱法同时测定水中六种阳离子

研究了用抑制电导离子色谱法一次进样同时测定水中Li^ ,Na^ , NH4^ ,Mg^2 ,Ca^2 的色谱法条件，相对标准偏差小于0．5％，加标回收率在97．5％－104．0％。在水质分析中运用t检验法，比较了用钙、镁离子浓度计算和传统方法测定的总硬度之间是否存在显著性差异。     

葡萄糖和水混合溶液多组分电解质热力学 Ⅱ.HCl-NaCl-d-Glucose-H_2O体系(5—45℃)

本文续前报在恒定溶液总离子强度I=1.00mol·kg~(-1),改变葡萄糖在混合溶液中的质量百分数x=5%、15%和20%的条件下,应用电动势法测定了无液接界电池(A)和电池(B)的电动势: Pt,H_2(1.013×10~5Pa)|HCl(m),d-Glucose(x),H_2O(1-x)|AgCl-Ag (A) Pt,H_2(1.013×10~5Pa)|HCl(m_A),NaCl(m_B),d-Glucose(x),H_2O(1-x)|AgCl-Ag(B) 其中x代表葡萄糖在水中的质量百分数,m_A和m_B分别是HCl和NaCl在混合溶液中的质量摩浓度。利用电池(A)的电动势数据得到了AgCl-Ag电极在d-Glucose-H_2O混合溶液中的标准电极电势Φ_m~0,讨论了HCl的迁移性质,利用电池(B)的电动势数据,确定了HCl在HCl-NaCl-d-Glucse-H_2O体系中的活度系数γ_A,实验结果表明:在恒定总离子强度下,HCl的活度系数服从Harned规则。HCl的迁移自由能与葡萄糖的质量百分数x成线性关系。计算了HCl     

温敏性聚合物复合体系低临界溶解温度的研究

研究了温敏性N-异丙基丙烯酰胺的均聚物(PNIPAm)及其共聚物P(NIPAm-co-KYD)与十六烷基三甲基氯化铵(CTAC)、乙二胺四乙酸(EDTA)、盐等复配体系的低临界溶解温度(LCST)的变化规律。单因素复配体系中,wEDTA为0.1%时,体系LCST从33℃降低到25℃,增大到0.2%时,LCST下降趋于缓慢;wCTAC在0.5%-3.0%范围内,LCST先上升后下降,但wCTAC在0.5%-1.0%内相转变很不明显,超过1.5%后相转变又趋于明显;而无机盐能使体系LCST线性下降;多因素复配体系中LCST变化较缓和,易于控制且相转变现象明显。     

EDTA—Cu配合物用于还原糖的测定

首次报道了应用ＥＤＴＡ（乙二胺四乙酸二钠盐）－铜配合物（ＥＣ）测定还原糖的分光光度法，结果表明，ｐＨ４～１１时ＥＣ的最大吸收波长为７３２ｎｍ，在ＨＣＯ－３ＣＯ２－３缓冲介质中，配合物ＥＣ的吸光度与还原糖在０７７～１６１ｍｇ（六碳糖）范围内有很好的线性关系，相关系数大于０９９８，样品测定回收率在９５％～１０５％之间。该法试剂易得、性质稳定，操作方便，灵敏度较高，取样量少于５ｍＬ。     

Electrode kinetics of Eu3+/Eu2+ reaction by cyclic voltammetry

The cyclic voltammetric behaviour of Eu³⁺/Eu²⁺ couple at hanging mercury drop electrode (HMDE) has been studied in chloride, bromide, iodide, thiocyanate and EDTA supporting electrolytes. The apparent rate constant and transfer coefficient for these systems have been calculated at various voltage scan rates, without using the data for standard or formal potential. The values have been compared with those obtained by earlier workers through other electrochemical methods.     

Analysis of nitriles at low parts per million levels by capillary gas chromatography

Two methods have been developed for the determination of trace levels of acetonitrile and propionitrile in light naphthas. One involves clean-up and preconcentration by medium pressure liquid chromatography (MPLC) in which nitriles are concentrated ten-fold while the complex hydrocarbon matris is removed. The concentrated solution is then analyzed by high resolution GC with flame ionization detection. The second method involves direct injection of samples into a capillary GC equipped with chemiluminescence nitrogen detection. The results and repeatability obtained from both methods are comparable. Preconcentration enables identification by GC-MS and simultaneous analysis of other polar species, with no need for selective detectors. Direct analysis is, on the other hand, much less time-consuming and requires less sample.     

Hydrolysis of DNA by cerium(IV)/EDTA complex

Homogeneous solutions are formed from equimolar amounts of Ce(NH₄)₂(NO₃)₆ and EDTA. These solutions hydrolyze single-stranded DNA far more efficiently than double-stranded DNA. In contrast, Ce(IV) hydroxide gel, obtained in the absence of EDTA, hydrolyzes both single-stranded and double-stranded DNAs at almost the same rates. In order to achieve this substrate-specificity sufficiently, the mole ratio of EDTA to Ce(NH₄)₂(NO₃)₆ must be 1.0 or greater. By using this remarkable specificity of Ce(IV)/EDTA complex, gap-site in substrate DNA is selectively hydrolyzed. The scission-site is modulated by use of appropriate combination of oligonucleotide additives. The reactions have been kinetically analyzed.     

壳聚糖修饰玻碳电极卷积伏安法测定环境水中的EDTA

制备了壳聚糖修饰玻碳电极 ,研究了Fe(EDTA) -在修饰电极上的吸附还原行为 ,用卷积伏安法通过Fe(EDTA) -的检测测定了环境水中的EDTA。在优化的实验条件下 ,峰电流值与 8.0× 1 0 -7～ 5 .0× 1 0 -6mol L的EDTA呈线性关系 ,回归方程为epp′ =0 .75 2 5c - 0 .661 3,r =0 .991 ,最低检出限为 5 .0× 1 0 -7mol L ,5次测定的相对标准偏差小于 5 .8%。对实际样品测定的回收率为98 1 %～ 1 0 5 % ,对比HPLC的结果 ,相对偏差小于 5 %。