Extractive spectrophotometric determination of silver(I) at the 10−7M level using 1,10-phenanthroline and tetrabromophenolphthalein ethyl ester
✍ Scribed by Tomozo Koh; Tatsuo Sugimoto
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 576 KB
- Volume
- 333
- Category
- Article
- ISSN
- 0003-2670
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✦ Synopsis
The determination of silver(I) is based on the formation of a chelate of silver(I) with l,lO-phenanthroline and its extraction into I ,2_dichloroethane as an ion par with tetrabromophenolphthalein ethyl ester. Quantitative extraction of the ion pair was achieved when the volume of a solution containing silver(I) was varied over 1 O-l 500 ml. The apparent molar absorptivities for silver(I) at 610nm are 1.82x lo61 molP' cm-' for a 200 ml volume of solution containing a silver(I), 3.65 x IO" for 400 ml of solution and 1.37x 10' for 1500 ml of solution, respectively. The absorbance of the extract is stable for at least one day in a glass-stoppered tube. A linear calibration graph was obtained over the range 3.6x 10-"-3x lo-' M silver(I) (0.16-I 2.9 pg of Ag' in 400ml); at the 2.25x lo-'M silver(I) level, the relative standard deviation (n=ll) is 0.52%. The method was successfully applied to assays of silver in silver solder and silver protein samples; the results obtained were in good agreement with the stated values.