Automatic catalytic titration of silver

An automatic method is described for the catalytic titrimetric determination of microgram amounts of silver. The method is simple and accurate, and is based on the inhibitory effect of silver ions on the iodide-catalysed Ce(IV)-As(III) reaction. The end-point of titration with iodide is determined either automatically by the second- derivative technique or from the recorded potentiometric or spectrophotometric curves. Microamounts of silver in the range 1–2000 μg were determined with relative errors of about 0.7%.