Determination of microgram quantities of silver in aluminium-, iron-, and nickel-base alloys

Trace quantities of silver in commercial nickel and its alloys are quantitatively extracted from 10% hydrochloric acid medium containing 2% ascorbic acid and 9% potassium iodide by a 5% solution of tri-n-octylphosphine oxide in 4-methylpentan-2-one (MIBK). The MIBK-extract containing the silver is then nebulized directly into an atomic-absorption flame. The sensitivity for the determination of silver in MIBK is about 6 times that for aqueous media. The proposed technique is accurate, rapid, and has a standard deviation of +/- 0.025 ppm at the 1 ppm level. The limit of detection is 0.2 ppm of silver. The method is also applicable to a number of elements in aluminium- and iron-base alloys.