| Research Abstract |
1. A silica-gel immobilized xanthurenic acid (4, 8-dihydroxyquinoline-2-carboxylic acid) was synthesized and it potential as an adsorbent for metal ions was studied. The silica-gel immobilized xanthurenic acid had an adsorption capacity of about 50 μmol/g for copper ion. This is more than twice that for silica-gel immobilized 8-quinolinol by the same method. Copper, lead and zinc were adsorbed quantitatively from the solution of over pH 1, 2 and 3, respectively.
Cadmium, nickel, cobalt and vanadium were adsorbed over pH 4. Many metal ions were adsorbed under a more acidic condition than the adsorbent, silica-gel immobilized 8-quinolinol, because xanthurenic has a carboxyl group in the structure. It was possible to determine sub μg/L levels of trace metals, such as copper, lead, nickel, cobalt, cadmium and vanadium and so on, after a 100-fold preconcentration using this adsorbent and ICP-AES or GFAAS.
2. Rapid and simple analysis method was developed for the determination of trace polyethylene oxide non-ionic surfactants using a chelation and an ion-pair extraction as principle.
3. Tristimulus colorimeter was used as instrument for the rapid simple and on-site measurement of trace cyanide, ferrous and phosphorous after collection as colored ion associate on an membrane filter.
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