Noboru Nomura

Automatic liquid chromatography of organic compounds : II. Adsorption chromatography of benzene derivatives on styrene-based cation-exchange resin☆

Abstract The adsorption chromatography of benzene derivatives on styrene-based cation-exchange resin has been investigated. Adsorption isotherms of benzene derivatives are discussed and the possibility of separation and quantitative treatment is considered for some cases of non-linear isothermal adsorption. The distribution coefficient and the height equivalent to a theoretical plate, important for separation and quantitative analysis, have been calculated for thirty-eight derivatives of benzene.

Automatic liquid chromatography of organic compounds : I. Microquantitative analysis of urea type compounds by automatic liquid chromatography with a thermal detection method

Abstract The separation of urea type compounds was studied by using thermal reaction energy detection automatic liquid chromatography. A strong polystyrene-based ion-exchange resin was used as adsorbent, activated in types of sulphonic acid, sodium sulphonate, and ammonium chloride. The highest thermal detection sensitivity on liquid chromatography, ± 3/10000°, full scale was tested while changing the concentration of the eluent, namely 1.0, 0.1, and 0.01 N hydrochloric acid and water. It was illustrated that the sensitivity and reproducibility of the thermal reaction energy detection method were superior to those of colorimetry in quantitative microanalysis of urea type compounds.

Automatic liquid chromatography of organic compounds : III. The relationship between the chromatographic behaviour and the chemical structure of benzene derivatives☆

Abstract The relationship between the distribution coefficients ( K D ) of benzene derivatives on the hydrogen and sodium forms of styrene-based strong cation-exchange resins, e.g. Bio-Rad AG 50W X8, and their chemical structures are discussed. A comparison of the K D values of the hydrogen and sodium forms of the resin, the effect of the size of the halogen atom on the K D values and of the additivities of the K D values with respect to the number of carbon atoms in the alkyl groups in alkyl phenyl ethers and alkylphenols and to substituents in phenol derivatives are considered.

Modified normal pulse polarography of alkali-metal ions in acid solution

Well-defined polarograms of five alkali-metal ions in 0.01M hydrochloric acid were obtained by means of modified normal pulse polarography. The method uses the procedure of anodic stripping chronoamperometry during the life-time of a drop from a dropping mercury electrode, namely preparation of electrode, accumulating step and anodic stripping step of a metal. The instantaneous polarographic currents were sampled only once per mercury drop after the fall of each pulse. The wave heights for alkali-metal ions by the present method are free from the interference caused by 0.01M hydrochloric acid. The present method is applicable to monitoring of alkali-metal ions in fluid acid streams.

Reversed-Phase Liquid Chromatography of Alkylphenols Depending on Their Dissociation Constants

Abstract The reversed-phase liquid chromatography of structural isomers of alkylphenols has been studied. Octyl-bonded silica gel was useful as stationary phase and addition of a trace of triethylamine to the eluent was effective for this purpose. The separation of nine structural isomers of alkylphenols, ethylphenols and xylenols, was accomplished by such liquid chromatographic system. Thus the good reproducibility of the capacity ratios was obtained. The increase of retention of the solute was not observed by addition of the ion-pair reagent to the eluent.

Ion-Pair Liquid Chromatography of Alkylanilines

Abstract The optimization of ion-pair liquid chromatography of structural isomers of carbon number two alkyl anilines has been studied. The shorter alkyl cha in bonded silica gel demonstrated the stereo selectivity. the alkyl chain length of ion-pair reagent ruled the equilibration of ion-pair formation. the longer chain of ion-pair reagent formed hydrophobic ion-pair and the shorter chain could not form ion-pair, and ionized solute formed ion-pair with polar ion which was a component of eluent. Three ethylanilines and six xylidines mixture was separated on an octadecyl-bonded silica gel column using an eluent containing methanol/water mixture with sodium 1-dodecanesul-fonate.

Modified reverse pulse polarographic behaviour of magnesium ion in aqueous solution

Modified reverse pulse polarography (MRPP) is proposed for measuring the quantity of a reduction product formed at the initial potential in reverse pulse polarography. A double potential-step method is employed for this purpose. MRPP has been applied to the study of the electrochemical behaviour of magnesium in aqueous solution. For magnesium the height of the MRPP anodic wave was proportional to concentration at low pH, but not in unbuffered neutral solution. This difference is attributed to formation of hydroxo-magnesium complexes because of depletion of hydrogen ions near the electrode in a neutral solution.

Application of modified normal pulse polarography and its differential mode to alkaline-earth metal ions in acid solutions

The simultaneous determination of alkaline-earth metal ions in acid solution was studied by modified normal pulse polarography. Well-defined waves were recorded for calcium, strontium and barium, but no limiting current was found for magnesium, because of its very negative reduction potential. The differential mode of this method gives peak-type polarograms and is useful for the simultaneous determination of species for which the half-wave potentials lie close together. The interference of dissolved oxygen was eliminated by the use of tetramethylammonium chloride as a supporting electrolyte.