Atomic Absorption Spectrometric Determination of Silver, Bromide and Iodide Ions in a Flow System Using an on-Line 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 NH 3 solutions, bromide was precipitated as AgBr and dissolved by S 2 O 3 =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 4.6×10 −9 M for silver when it is precipitated as AgCl and dissolved by s 2 O 3 2− solution, 1×10 −6 M for bromide when it is precipitated as AgBr and dissolved by S 2 O 3 2− solution and 1×10 −6 M for iodide when it is precipitated as AgI and dissolved by CN − solution.