Abstract: This paper describes the development and optimization of a flow injection analysis (FIA)manifold for the simultaneous determination, by atomic absorption spec-trophotometry (AAS)and flame emission photometry (FP), of total calcium and potassium in blood serum. A dialysis unit is used in this setup to ensure a high dilution of potassium and to divide the sample plug before it reaches the detectors. The advantages of an optimization algorithm, modified Powell's method, to attain the best performance of the setup are demonstrated by a restricted experimental trial. Lastly, the quality of the results obtained with this method is evaluated with two pools of control sera.

Key words: Flow-injection analysis, Two-component determination, Potassiumand calcium, Blood serum, Powell's optimization