Amylose-iodine complex formation without KI: Evidence for absence of iodide ions within the complex

Amylose-iodine (AI) complex has been synthesized in aqueous solution without added KI. Complex formation (with solid iodine in amylose solution) is maximized at approximately 35 °C and decreases beyond that temperature. Ion-selective electrode (ISE) measurements of an aqueous solution of iodine and AI complex indicate that there is no change in the I^- ion concentration when the complex forms. This suggests that I^- ions (including I₃^-, I₅^-, and others) cannot be involved in forming the AI complex. The present work also reports a new and simple method for providing both the iodine-binding capacity (IBC) of amylose and the dissociation mechanism for the AI complex.