Determination of Silver in Water by Flame Atomic Absorption Spectrometry

Abstract A precise method to determine Ag in natural water using flame atomic absorption spectrometry is described. This method consists of the precipitation of Ag with Fe3+ and Na2S, and the separation of Ag into methylisobutylketone (MIBK) using sodium N,N-diethyl-dithiocarbamate (DDTC) as a complexing agent after redissolving the Ag in the precipitate. Silver in the MIBK is determined by direct aspiration into a flame atomic absorption spectrophotometer. The amounts of Fe3+ and Na2S that should be added and the appropriate pH for Ag precipitation were investigated. The results showed that more amounts of both Fe3+ and Na2S were needed for Lake Kasumigaura water than for distilled water to recover all the Ag added to the water samples. The detection limit (SIN = 2) for the method was 0.005 μ Ag L−1. Using the method, Ag concentrations in some water samples taken from rivers, lakes and ponds were determined. The Ag concentrations ranged from < 0.005 to 0.210 μ L−1, which were lower than the value reporte...