engleski

Direct potentiometric determination of starch using a platinum redox sensor

Here, we describe the development of a platinum redox sensor for the direct potentiometric quantification of starch in solution. The sensor measures the decrease in free triiodide ion after it complexes with starch to form a starch-triiodide complex. This decrease was, therefore, correlated with starch concentration, and the composition and stability of the potassium triiodide solution were optimized. The starch-triiodide complex was characterized potentiometrically at variable starch and triiodide concentrations. We also propose a response mechanism for the platinum redox sensor towards starch and an appropriate theoretical model. The optimized method exhibited satisfactory accuracy and precision and was in good agreement with a standard spectrophotometric method. The sensor was tested over a range of 0.4-9 mg starch, with recoveries ranging from 97.8 % to 103.4 % and a detection limit of 0.01 mg starch.

starch; potentiometric sensor; direct potentiometry; triiodide

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