EFFECTS OF ACETONE, ETHANOL, ISOPROPANOL, AND DIMETHYL-SULFOXIDE ON AMYLOSE-IODINE COMPLEX

The amylose-iodine (AI) complex formation was studied by absorption sp ectra in water and water containing varying proportions of ethanol,ace tone, isopropanol and dimethyl sulfoxide (DMSO). Complex formation is most favored in pure water and decreases as the proportion of nonaqueo us solvent is increased. A decrease in the absorbance intensity at aro und 615 nm (for AI complex) is accompanied by a peak shift towards 550 nm and an increased absorbance at around 350 nm (for unbound iodine). The amount of the nonaqueous solvent added, as well as the order in w hich it is added relative to amylose and iodine solution, change remar kably the extent of the AI complex formation. A mechanism of the compl ex formation is proposed.