New scheme for complete silicate analysis based on ion-exchange chromatography

Summary A new method has been developed for the quantitative separation and determination of Si, Ti, Al, total iron, Mn, Mg, Ca, Na, K and P in silicate rock samples. Silicate is decomposed by fusion with a mixture of boric acid and lithium carbonate and the melt is dissolved in 1 M hydrochloric acid. The diluted sample solution is loaded on a column of AG 50W, X-8 sulfonated polystyrene cation-exchange resin and the elements Fe, Mn, Ti, Al-Mg and Ca are eluted by stepwise changing eluting agents. Si and P are eluted together without retention and are spectrophotometrically determined in the effluent without any separation. The Al-Mg mixture is further separated by simple anion exchange in the same eluent system as used in the preceding cation-exchange chromatography. Na and K are accurately determined in an aliquot of the original sample solution without any separation by flame atomic absorption spectrometry. Recoveries of 10 major and minor elements are satisfactory. Results are quoted of the quantitative analyses of four standard rocks of the U. S. Geological Survey and Geological Survey of Japan.

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Neues Schema zur quantitativen Gesamtanalyse von Silicaten durch Ionenaustausch-Chromatographie

Zusammenfassung Eine neue Methode wurde entwickelt zur quantitativen Trennung und Bestimmung von Si, Ti, Al, Gesamt-Fe, Mn, Mg, Ca, Na, K und P in Proben von Silicatgestein. Hierbei wird das Silicat durch Schmelzen mit einer Mischung von Borsäure und Lithiumcarbonat aufgeschlossen und die Schmelze in 1 M Salzsäure gelöst. Die verdünnte Lösung wird auf eine Kationenaustauschersäule (AG 50W, X-8, sulfoniertes Polystyrol) gegeben und die Elemente Fe, Mn, Ti, Al-Mg und Ca werden mit Hilfe von stufenweise variierten Elutionsmitteln eluiert. Si und P werden gemeinsam ohne Retention eluiert und ohne Trennung spektralphotometrisch im Eluat bestimmt. Al und Mg werden durch Anionenaustausch mit demselben Elutionssystem wie in der vorangegangenen Kationenaustausch-Chromatographie getrennt. Na und K können zuverlässig aus der ursprünglichen Lösung ohne Trennung mittels Flammen-AAS bestimmt werden. Die Wiederfindung für 10 Hauptund Nebenbestandteile ist zufriedenstellend. Das Verfahren wurde zur Analyse von vier Standardgesteinen des US Geological Survey und des Geological Survey of Japan angewendet.

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This work was in part supported by a Grant-in-Aid for Scientific Research (No. 60540364) from the Ministry of Education, Science, and Culture.     

Combined anion-exchange separation and spectrophotometric determination of traces of titanium in sea water

Summary Traces of titanium in sea water have been preconcentrated by anion-exchange from acidified samples in the presence of thiocyanate. Titanium adsorbs strongly on a column of Amberlite CG 400 (SCN^–) and can be stripped easily by elution with 2 M hydrochloric acid — 1.5% hydrogen peroxide solution. Titanium in the effluent is determined spectrophotometrically with diantipyrylmethane as colour reagent. The combined method allows to determine traces of titanium very selectively and sensitively in sea water as well as non-saline water on a 41 sample basis. The method yields a coefficient of variation of 7% at a titanium level of 0.4 g per l.

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Kombinierte Anionenaustauscher-Trennung und spektralphotometrische Bestimmung von Titanspuren in Meerwasser

Zusammenfassung Titanspuren wurden in Gegenwart von Thiocyanat durch Anionenaustausch aus der angesäuerten Probe angereichert. Titan wird an Amberlite CG 400 (SCN^–) stark adsorbiert und kann durch Elution mit 2M HCl — 1,5% H₂O₂ leicht abgelöst werden. Im Eluat wird es spektralphotometrisch mit Diantipyrylmethan bestimmt. Die kombinierte Methode gestattet eine selektive und empfindliche Bestimmung in einer 41-Probe von Meer- oder auch Süßwasser. Für einen Gehalt von 0,4 g Ti/l beträgt der Variationskoeffizient 7%.

     

Comparison between the effects of ultrasound and γ-rays on the inactivation of Saccharomyces cerevisiae: Analyses of cell membrane permeability and DNA or RNA synthesis by flow cytometry

The effects of 200 kHz ultrasonic irradiation on DNA or RNA formation and membrane permeability of yeast cells were investigated by flow cytometry and compared with those of ⁶⁰Co γ-ray radiation. Colony counting analyses were also performed for comparison. It was observed that the colony-forming activity of yeast cells was not affected by small doses of ultrasonic irradiation, but was closely related to the amounts of sonolytically formed hydrogen peroxide at concentrations of more than 80 μM. On the other hand, γ-rays directly retarded colony-forming ability in addition to the effects of radiolytically formed hydrogen peroxide. The results obtained by flow cytometry also indicated that the amounts of DNA or RNA formed decreased with an increase in ultrasonic irradiation time without any threshold. These results indicated that flow cytometry can show early growth activities, but that colony counting analyses are insufficient to evaluate continuous and quantitative changes in these activities. In addition, by analyzing the amounts of DNA or RNA formed in the presence of the same amount of hydrogen peroxide, it was found that DNA or RNA formation behavior in the presence of hydrogen peroxide with no irradiation was similar to that following ultrasonic irradiation. These results suggested that similar chemical effects due to the formation of hydrogen peroxide were produced during ultrasonic irradiation. In addition, physical effects of ultrasound, such as shock wave, hardly contributed to cell inactivation and cell membrane damage, because relatively high frequency ultrasound was used here. In the case of γ-ray radiation, direct physical effects on the cells were clearly observed.     

Hydrogenation effects in metalloporphycenes: synthesis and redox behavior of Ni(II)-tetra(n-propyl)dihydroporphycene

Hydrogenated tetrapropylporphycenes, 2,3-dihydro-2,7,12,17-tetrapropylporphycene 1 and its Ni(II) complex 2, have been prepared and the hydrogenation effects on their electronic structure characterized. A one-electron reduction of 2 promotes dehalogenation of organic halides whose observation is unprecedented for the porphycene compounds.     

Atmospheric concentrations of sulfur dioxide, nitrogen oxides, ammonia, hydrogen chloride, nitric acid, formic and acetic acids in the south of Vietnam measured by the passive sampling method.

A passive sampling method was applied to measure the concentrations of air pollutants, such as sulfur dioxide, nitrogen oxides, ammonia, hydrogen chloride, and nitric, formic and acetic acids, in the ambient air at four test sites in the southern region of Vietnam. The monthly averages and the average concentrations of air pollutants during the period from July 2001 to September 2002 are reported here. The concentrations of air pollutants varied widely, depending on the test sites and the sampling periods. The average concentrations of sulfur dioxide in the air during the period from July 2001 to September 2002 at the four test sites were 3.3-16.9 ppb, and those of nitrogen dioxide were 5.4-12.8 ppb. The concentrations of nitrogen monoxide and hydrogen chloride were very low at all of the test sites. The observed concentrations of all of the above-mentioned pollutants were lower than those of the Vietnamese standards of air pollutants.     

Synthesis of a series of multiply meso-acetoxylated porphycenes

A series of multiply meso-substituted porphycenes has been prepared by acetoxylation of 2,7,12,17-tetra-n-propylporphycene (H₂TPrPc), and the molecular structure of 9,10-diacetoxy-2,7,12,17-tetra-n-propylporphycene (2a) determined by single-crystal X-ray diffraction analysis. The ¹H NMR and optical properties have also been investigated.     

Preconcentration and selective determination of traces of tin in natural waters

A combined preconcentration-photometric determination technique has been worked out for trace concentration of tin in fresh and sea waters. After refluxing the sample acidified to 1M HCl for 2 h, tin is preconcentrated by anion-exchange in the presence of thiocyanate and recovered by elution with dilute HNO₃. Tin is then generated as stannane, caught in permanganate solution, and determined spectrpphotometrically with phenylfluorone. The results are quoted on the determination of tin in several fresh and sea waters in the order of submicrogram of tin per litre. The results for tin are in good agreement with those obtained for these samples by manganese dioxide coprecipitation-hydride generation-phenylfluorone spectrophotometric method that is also newly developed.