Ion chromatographic system with a novel switching suppression device

Ion chromatography (IC) has been a powerful tool for measuring ionic species in environmental samples such as tap, river and drain waters. Suppressor modules (membrane and disposable column types) have been used for reducing the background of a baseline. A new type of suppressor device, which has a suppressor resin and switching valve was developed. Fresh ionic resin is introduced into a groove for each analysis to perform the suppression of the working eluent. The eluent composition for obtaining higher sensitivity and better resolutions among ionic species and carbonate ion was also investigated. Although carbonate buffers are used for ion separation in general, the separation of carbonate ion from other ions was not achieved. A borate eluent resulted in good resolutions and higher sensitivity. A new column was also developed for obtaining higher column efficiency and resolution. The optimization of anion separation using a new IC system (IC-2001) that consists of a new suppressor device, an anion-exchange column (TSKgel SuperIC-Anion, 150x4.6 mm), an autosampler, a conductivity cell and a pump in a compact module is described.     

Molecular-level chiral discrimination and induction

The review describes the mechanism of chiral discrimination of racemic amines upon crystallization and the induction of chirality in organic reactions by using them as chiral auxiliaries. In order to form conglomerates, which can be resolved into the two enantiomers upon alternative seeding, both formation and packing of 2₁-columns are essentially very important. On the other hand, in order to achieve high efficiency in resolution through diastereomeric salt formation, which is the most practical method, one of a pair of diastereomeric salts derived from a racemic amine and an enantiomerically pure resolving agent should at least have two 2₁-columns and planar boundary surfaces in its crystal structure. On the basis of this knowledge, we developed several artificial chiral auxiliaries such as erythro-2-amino-1,2-diphenylethanol,cis-2-amino-1-acenaphthenol, andcis-2-amino-3,3-dimethyl-1-indanol. These were found to be very efficient chiral auxiliaries in asymmetric inductions: alkylation of chiral imines, catalytic borane-reduction, and alkylation of chiral N-acylated oxazolidinone.     

On the synthetic approach to the protopine alkaloids

The synthetic approach to the protopine alkaloids is described. Efficient construction of the alkaloid models 16a and 16b was accomplished by the general synthetic method consisting of photo-oxygenative ring enlargement of tetrahydrobenzindenoazepines 13a and 13b by singlet oxygen and further elaboration of the resultant 10-membered amido-ketone products 14a and 14b.     

Corrections to νe−νμ universality in neutral current interactions

We examine the effects of higher-order corrections on the universality between ν_μ and ν_e in the Weinberg-Salam model. The leading correction to neutral current amplitudes is an apparent difference in the values of sin²θ as measured by ν_μ and ν_e beams. The difference is .     

High field magnetization of europium-graphite intercalation compound C6Eu

The whole magnetization curve of the first stage compound C₆Eu has been measured by using pulsed fields up to 400 kG below 40 K. For H ⊥ c, c being the crystal c-axis, four regions are observed in the magnetization curve; I) the initial magnetization region with an apparent moment of ～ 0.6micro_B per Eu ion (H < 12 kG), II) the intermediate region with nearly constant moment of 2.2 – 2.7 micro_B, which corresponds to $\text{1}\text{3}$ the full moment of Eu²⁺ ion (22 < H < 82 kG), III) the region of a linear field dependence (82 < H < 205 kG), and IV) the saturation region above 205 kG, where the saturation moment is found as 6.2 micro_B. For H//c, the magnetization increases monotonically and approaches to a saturation value corresponding to 6 micro_B above 240 kG.