Tsugio Takeuchi

Studies of open-tubular micro-capillary liquid chromatography: II. Chemically bonded octadecylsilane stationary phase

Abstract A chemically bonded octadecylsilane stationary phase was successfully prepared on the inner glass surface of a micro-capillary tube of I.D. 60 μm. Using these capillary columns of length 3–20 m, several aromatic compounds were separated completely with methanol—water or acetonitrile—water as the mobile phase at a linear velocity of 0.3–1.3 cm/sec.

Studies of open-tubular micro-capillary liquid chromatography : IV. Soda-lime glass columns treated with alkaline solution

A soda-lime glass capillary treated with an alkaline solution was used as an adsorbent column for the separation of aromatic amines and phthalates in the normal-phase mode. The best adsorbent column for open-tubular micro-capillary liquid chromatography was made by treatment with 1 N sodium hydroxide solution at 25–54° for 2 days.

Characteristics of S2 emission intensity with a flame photometric detector

Abstract The molecular emission from sulphur compounds was studied by using a flame photometric detector and determining its intensity as a function of the composition of an air-hydrogen flame and of the concentration of the sulphur compounds. The relationship between the intensity of emission and the amount of sulphur in the compound is given by where i E is the intensity of the emission, M the amount of sulphur and i 0 and n are constants for a given experimental flame condition. The value of n varies between 1.69 and 2.00, depending on the flame conditions. The variations in the values of i 0 and n are discussed by considering reaction kinetics. The recombination reaction of sulphur atoms in a flame, which is the rate-determining step, is affected by the experimental conditions. Therefore, the relationship between the intensity of the emission and the amount of sulphur-containing compounds varies considerably with the flow-rate of air and hydrogen in the burner.

Interferences of S2 molecular emission in a flame photometric detector

Abstract The presence of gaseous non-sulphur-containing organic compounds in a carrier gas causes a decrease in the response of flame photometric detectors. The way in which such organic compounds interfered with the response of sulphur-containing compounds in the flame photometric detector was determined. The interference by organic compounds increases exponentially with increased in concentration of the substances. The interference by an organic compound is, however, independent of the concentration of sulphur-containing compounds in the presence of a certain concentration of the organic compound, and it was found that the decrease in the response of a flame photometric detector can be explained by inactivation of the excited S, species by its combination or collision with and/or its degradation products.

Trace analysis by flameless atomic-absorption spectrometry

The operating conditions of an atomic-absorption system based on flameless atomization have been investigated for trace analysis for Al, Cr, Cu, Fe, Mg and Mn. The sample solution on a tantalum strip was atomized by electrical heating in an inert atmosphere within an absorption chamber. This technique allows the use of small sample sizes and results in a higher sensitivity than that with the conventional flame technique. Some interference effects and applications were investigated.

Gel permeation chromatography of the cyclic monomers and oliglmers in nylon 6 and nylon 66

Abstract The cyclic monomers and oligomers in nylon 6 and nylon 66 were separated and determined by gel pearmeation chromatography. The gels used in the experiment were Sephadex G-15 and Bio-Gel P-4. The ethanol extracts of nylon 6 and nylon 66 were dissolved in 0.1 N hydrochloric acid which was used as an eluant. The effluent was introduced into a flow cell and the absorbance at 210 mμ was measured continously by means of a spectrophotometer. The method is applicable to 1–5 mg samples or less and the time needed for chromatography is less than 6 h. The presence of linear oligomers does not affect the determination of the cyclic oligomers. Linear relationships between log M and several elution values, vis . V e , V e / V t , V e / V o , K d , and V e /( V o + V i ), have been confirmed for the cyclic monomer and oligomers of nylon 6. Deviation from linearity of the elution values of the cyclic dimer of nylon 66 implies that the dimension of the dimer is contracted in a solution compared with others.

Ion chromatography with micropacked alumina columns

SummaryMicropacked alumina columns were applied to ion chromatography. Inorganic anions and cations could be simultaneously separated by using an appropriate mobile phase. The analyte ions were detected indirectly by using a UV detector.

Liquid chromatography/fast-atom-bombardement mass spectrometry of nonionic detergents

SummaryMicrocolumn liquid chromatography (LC) combined with fast-atom-bombardment mass spectrometry (FABMS) was applied to the analysis of nonionic detergents. The porous silver filter attached to the top of the capillary fused-silica tubing worked as the interface for coupling of micro LC and FABMS.

Spectroscopic studies of microwave-excited plasma

Manganese solution was sprayed into a microwave-excited plasma torch (2450 MHz and ca. 200 W), whose profile was examined; the electron temperature, the degree or ionization and the total number of atoms and ions were estimated. Effects of alkali and alkaline earth metals were found to depend on the ionisation potentials of both manganese and the added metal.

Gel permeation chromtography of the linear monomer and oligomers in polyamides

Abstract The linear monomers and oligomers in nylon 6, nylon 66, and nylon 12 were separated and determined by gel permeation chromatography using Sephadex LH-20 as the gel and 0.05 N HCl—methanol as eluant. The water—ethanol extractables of the polyamides were reacted with 2,4-dinitrofluorobenzene and the reaction solution was chromatographed. The effluent was channeled into a flow cell and the absorbance of the DNP-derivatives of the linear monomer and oligomers separated was measured continuously by a spectrophotometer in the 370 to 450 mμrange. The cyclic monomers and oligomers did not interfere with the separation and determination of the linear monomer and oligomers. Higher oligomers, up to the octamer of nylon 6, the tetramer of nylon 66, and the hexamer of nylon 12, were separated and determined. As little as 0.01 μmole of the DNP-derivatives has been determined. A linear relationship was obtained betwwen the elution volume and the logarithm of the molecular weight of monomer and oligomers from which that of the dinitrophenyl group had been subtracted.