title: Direct potentiometric determination of starch using a platinum redox sensor.
abstract: 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 optimised. 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 optimised 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.
authors.affiliation: Department of Chemistry, Josip Juraj Strossmayer University of Osijek, F. Kuhača 20, 31000 Osijek, Croatia. nikola.sakac@gmail.com
authors.forename: Nikola
authors.initials: N
authors.lastname: Sakač
authors.forename: Milan
authors.initials: M
authors.lastname: Sak-Bosnar
authors.forename: Marija
authors.initials: M
authors.lastname: Horvat
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D057230:Limit of Detection; D010084:Oxidation-Reduction; D010984:Platinum / Q000737:chemistry; D011199:Potentiometry / Q000379:methods*; D013213:Starch / Q000032:analysis*
chemical_list: D010984:Platinum; D013213:Starch