Tairoku Yano

Analytical application of organic reagents in hydrophobic gel media—I: General principle and the use of dithizone gel☆

Two types of hydrophobic gel particles containing dithizone were prepared, either by the swelling of low cross-linkage polystyrene beads with a dithizone solution in chlorobenzene, or by the gelatinization of a dithizone solution with dibenzalsorbitol. The extraction capacity of the gel particles for metal ions such as mercury, cadmium, zinc and lead from dilute aqueous solution, was investigated at various dithizone concentration and pH values. A column packed with such gel particles is found to be useful for the selective preconcentration or the selective trapping of specific metal ions at low concentration levels.

Spectrophotometric determination of water in organic solvents with solvatochromic dyes—II

The correlation between the absorbance at a fixed wave-length of a betaine dye in an organic solvent and the water content of the same solvent has been investigated. The betaine dyes investigated are 2,4,6-triphenyl-N-(3,5-diphenyl-4-hydroxyphenyl)pyiidinium betaine (I), 1-methyl-8-hydroxyquinolinium betaine (II), 1-methyl-6-hydroxyquinolinium betaine (III) and 2-methyl-5-isoquinolinium betaine (IV), and the organic solvents are ethanol, isopropanol, acetone, dioxan, acetonitrile and pyridine. The possibility of determining a trace amount of water in an organic solvent is demonstrated. The sensitivity of the method depends on solvent and dye but for example, 0.06 mg of water in 1 ml of acetonitrile can be detected with III with an ordinary spectrophotometer. The limitations of practical applications are discussed.

The Analytical Applications of Organic Reagents in Hydrophobic Gel Media

Abstract The use of hydrophobic gel particles containing an organic solvent solution of chelating agents is described. With the use of a column of such gel particles, it is possible to trap or concentrate metal ions selectively on the gel particles from very dilute aqueous solution. A method for the semi-quantitative determination of trace amount of metal ions is proposed.

Analytical application of organic reagents in hydrophobic gel media-IV Selective preconcentration of Cobalt(II) with 1-nitroso-2-naphthol gel

Cobalt is selectively extracted from solution onto gel beads impregnated with 1-nitroso-2-naphthol. A concentration factor of 67 has been achieved by passing 2 litres of sea water containing 0.05 ppm of cobalt over the beads at a flow-rate of 40 ml/hr. The cobalt is eluted from the beads with methyl isobutyl ketone.

Dual-wavelength spectrophotometric determination of traces of mercury(II) with solubilized dithizone: An approach to simplified analytical procedures for environmental pollutants

Abstract A simple spectrophotometric procedure is described for the determination of traces of mercury, with solubilized copper(II) dithizonate. Sample water containing 0.05–0.25 μg of mercury(II) is mixed with an aqueous solution of copper dithizonate containing Triton X-100 at pH 1 (H2SO4 ). After 5 min, dual-wavelength photometry is used to measure the difference in absorbances at 507 and 493 nm, which is proportional to the mercury concentration. The advantages are that no reagent blank is necessary and the equipment is simple. Few cations interfere; silver(I) and iron(III) can be masked by chloride and fluoride, respectively.