ATOMIC-ABSORPTION SPECTROMETRIC DETERMINATION OF SILVER, BROMIDE AND IODIDE-IONS IN A FLOW SYSTEM USING AN ONLINE PRECONCENTRATION TECHNIQUE

Silver, bromide and iodide ions are determined using a flow analysis system and precipitation as a reconcentration technique. The precipitate formed by reaction of cation and anion in a Tygon tube containing glass beads and connected to the atomic absorption spectrophotometer is dissolved by passing a solution of suitable dissolving agent. The dissolving agent dissolves the precipitate and the formed soluble complex is transported to the atomic absorption spectrophotometer, yielding a signal. The signal height is proportional to silver concentration which is in turn proportional to anion concentration. Silver was precipitated as AgCl and dissolved by S2O3 =, CN- and NH3 solutions, bromide was precipitated as AgBr and dissolved by S2O3 = and CN- solution and iodide was precipitated as AgI and dissolved by CN- solution. This method has proved to be sensitive, simple and precise. The lowest detection limit is 4.6 x 10(-9)M for silver when it is precipitated as AgCl and dissolved by S2O3(2-) solution, 1 x 10(-6)M for bromide when it is precipitated as AgBr and dissolved by S2O3(2-) solution and 1 x 10(-6)M for iodide when it is precipitated as AgI and dissolved by CN- solution.