Reversible replication between ordered mesoporous silica and mesoporous carbon

Highly ordered mesoporous silica can be regenerated from a mesoporous carbon CMK-3 that is a negative replica of mesoporous silica SBA-15, indicating reversible replication between carbon and inorganic materials.     

A thin-layer electrochemical detector coated with nafion film for liquid chromatography

The selectivity and analytical application of a thin-layer electrochemical detector comprised of glassy carbon electrode coated with Nafion film were investigated. As a result of the ion-exchange characteristics of the Nafion polymer, the selectivity and stability were improved greatly. The coated electrode has a good response only for cations with the same sensitivity as an uncoated (bare) electrode, but not for anions, and the response for neutral molecules is decreased three-fold. The diffusion of electroactive compounds in Nafion film is discussed based on the results of flow injection experiments. The peak current at the coated electrode was independent of the flow-rate of the mobile phase. Electrode poisoning due to protein adsorption was minimized. The use of 30% methanol or 10% acetonitrile in the mobile phase did not affect the performance of the coated electrode. Various analytes having three kinds of charge state, i.e., anionic, cationic and neutral, were tested. Liquid chromatography with electrochemical detection of ascorbic acid, norepinephrine, epinephrine, dopamine and uric acid was demonstrated.     

Laser-assisted electron capture by a fast proton from a hydrogen atom

The first Born approximation is used to study the laser-assisted electron capture by a fast proton from a hydrogen atom. The laser modification on differential cross section peaks sharply in the forward direction. With the impact energy increasing, the change in integral cross section becomes notable. The more intense the laser, the greater the cross section is; the lower the frequency, the greater the cross section.     

Chemie der Seltenerdmetalle, 19. Mitt.: Dissoziation des Ce(III)-succinats im sauren Gebiet

Zusammenfassung Die Dissoziation von Ce₂ Suc ₃·3 H₂O^** in Perchlorsäure-Lösungen wurde verfolgt und die Dissoziationskonstanten der Succinationen: (CeSuc)⁺ und (CeSuc ₂)^– unter Benützung einer Löslichkeitsmethode in 1m-NH₄ClO₄-Lösung bei 25°C bestimmt. Die Löslichkeitsprodukte von Ce₂ Suc ₃: [Ce³⁺]²[Suc ^2–]³, [CeSuc ⁺]²[Suc ^2–], [CeSuc ⁺][CeSuc ₂ ^–] wurden bestimmt.

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The dissociation of Ce₂ Suc ₃·3H₂O in perchloric acid solutions was investigated. The dissociation constants of the succinate ions (CeSuc)⁺ and (CeSuc ₂)^– were determined inM-NH₄ClO₄ at 25° using a solubility method and the solubility products of Ce₂ Suc ₃, i. e. [Ce³⁺]²[Suc ^2–]³, [CeSuc ⁺]²[Suc ^2–], [CeSuc ⁺][CeSuc ₂ ^–] measured.

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18. Mitt.:R. Pastorek, Lanthantartrate im neutralen und alkal. Bereich. Mh. Chem.99, 676 (1968).     

An HPLC and EPR investigation on the stability of DMPO and DMPO spin adducts in vivo

Application of the spin trapping technique in intact animals requires an understanding of the stability and distribution of the spin traps and their spin adducts in vivo. We studied the stability of DMPO in vivo in mice using HPLC and the stability of spin adducts of DMPO by EPR in plasma, whole blood, peritoneal fluid, and homogenized heart tissue of the rat. At 15 minutes after intraperitoneal injection DMPO had similar concentrations in the liver, heart, and blood of the mice and 40% remained in the organs 2 hours after the injection. In contrast, the spin adduct DMPO-OH was short lived, with a half-life of 3.0 minutes in plasma, and was not detectable 1 minute after formation in whole blood and homogenized heart tissue. The carbon centered spin adduct DMPO-CH(OH)CH₃ was more stable, having half-lives of 16, 11, 3.6, and 0.79 minutes in plasma, peritoneal fluid, whole blood, and homogenized heart tissue, respectively. The spin adduct DMPO-SO₃ was sufficiently stable for the adduct to be observed directly from living mice.     

Molecular intercalates

The paper deals with the relations between host lattices and guest molecules. Several types of interaction of the guest molecules and the host material are explained and some conclusions are made about the arrangement of various guest molecules in the van der Waals' gap.     

N,N,N,′N′-四丁基丁二酰胺的合成及其萃取稀土离子Pr(Ⅲ)的研究

合成了四取代双酰胺萃取剂N,N,N,′N′-四丁基丁二酰胺(TBSA),并对萃取剂的结构进行了表征。研究了其萃取Pr(Ⅲ)的性能,考察了硝酸浓度、萃取剂浓度、硝酸锂浓度以及温度等对萃取分配比的影响。萃取反应在298K时,TBSA以甲苯为稀释剂时的热力学焓变为-12.83 kJ/mol。萃合物的组成结构为Pr(NO3)3.3TBSA。     

Theory and applications of ion-selective electrodes Part III

This review of ion-selective electrodes is arranged in the same way as Parts I and II. The continuous growth of the whole subject should be noted. Theory has particularly progressed through mechanistic studies. Among new types of electrodes, ISFET systems have become important. Among new applications of both solid and liquid membrane electrodes, the fluoride electrode still predominates, closely followed by potassium electrodes. In the field of biological and medical applications, the steady growth is significant. More than 800 papers published between mid-1976 and the end of 1978 are mentioned in the review.