OSCILLATING FLOW-INJECTION STRIPPING POTENTIOMETRY

A fully computerized flow injection (FI) manifold with a peristaltic p ump allowing periodic alternation of the now direction and incorporati ng a detector system capable of performing potentiometric stripping an alysis (PSA) is outlined. The measuring technique has been named oscil lating flow injection stripping potentiometry (OFISP). It combines the attractive features of both traditional flow injection analysis (FIA) and batch PSA and at the same time overcomes some of the most serious drawbacks of the latter resulting from the fact that potentiostatic d eposition and chemical stripping occur in the same solution. An experi mental study of the influence of the main parameters of the flow syste m on its behaviour was performed using Cu(II) solutions in the mu g l( -1) concentration range as samples. The potentiostatic deposition was carried out on an Hg precoated glassy carbon electrode and Hg(II) ions were utilized as oxidant in the chemical stripping step.