Silver concentrations in natural water are very low and generally require preconcentration prior to instrumental analysis. Solvent extraction and anion exchange methods are the most commonly applied techniques for the determination of Ag in water samples. In this study, solvent extraction and anion exchange techniques are combined and modified to an ¡§organic complexation-acid extraction¡¨ method. The procedure developed involves four steps: (1) a buffer is added and the pH of the solution is adjusted for optimization purpose; (2) APDC and DDDC chelating agents were added and the silver in the solution is organically complexed; (3) the solution was passed through AG-MP1 anion exchange resins and silver complexes and their flocculant were retained and; and (4) acid solutions were used to extract silver from the column for subsequent determination of sliver by a graphite furnace atomic absorption spectrophotometer. After the experiments, the optimal procedures were established as the following: The pH of a 1-L aqueous sample was adjusted to ~4.5 by adding a buffer solution. Aliquots of 2.5-mL solutions containing chelating agents (2% w/v each of APDC and DDDC) were added. After being mixed, the solution was passed through an anion exchange column (AG MP-1) and silver complexes (and their flocculated particles) retained. Two 0.5¡VmL aliquots of 6, 4 and 2 N HNO3 were used to extract Ag from the column, aided by sonication for 3 min during each extraction procedure. The final volume is 3 ml, yielding a concentration factor of ~333. Determination of sliver was done by a graphite furnace atomic absorption spectrophotometer. The detection limit is 1.03 pM. This method was suitable for both freshwater and seawater samples, and was successfully applied for the determination of Ag in coastal and off-shore seawaters collected from coastal region off southwestern Taiwan.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0911112-184442 |
| Date | 11 September 2012 |
| Creators | Chen, Wei-Han |
| Contributors | Liang-Saw "CAT" Wen, Su-Cheng Pai, Kuo-Tung Jiann |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0911112-184442 |
| Rights | unrestricted, Copyright information available at source archive |
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