キレート樹脂検知管によるクロム酸イオンの迅速簡易定量

抄録

A chelating resin to analyze chromate ions was prepared by mixing 0.02% diphenylcarbazide solution (100cm³) and 1gr of 50-100mesh Dowex 2×8 anion exchange resin. After stirring for 25min by magnetic stirrer the resin was filtered off from the solution and dried at 50°C in air to sustain about 25% of the original water content. The chelating resin thus prepared was stored in nitrogen atmosphere in the dark, it was stable for 6 months. A 200mg portion of the resin was put in a glass tube of 2.55mm∅×70mm, both ends of which were plugged with cotton wool. For determination, 2cm³ of sample solution was sucked into the column in 4min and the length of red-violet colored layer appearing in the column was measured. For producing the color, it was neccessary to add H₂SO₄ at concentrations 0.1-0.25mol dm^-3. Addition of H₂SO₄ was done by passing the sample solution to a column of silica gel (50-80mesh, 100mg) containing 0.13mol H₂SO₄/dm³ prior to the determination. Diverse cations were preliminarily removed by cation exchange, a column containing Dowex 50W×2 (100-200mesh, 100mg) was placed before the silica gel column. Temperature of the sample solution was kept at 10-25°C. Determination of chromate ion was possiblefor concentrations 0.1-500ppm in about 6min within an error of±10%.