Amylose and amylopectin as reagents for the flow-injection determination of elemental iodine

Abstract

The complexation reactions of elemental iodine with amylopectin and amylose were studied under flow conditions with spectrophotometric signal detection. It was found that the average hydrodynamic molecular weights of amylose and amylopectin are 260 000 and 430 000, whereas the coefficients of sedimentation are 3.44 × 10−13 and 7.15 × 10−13 s, respectively. It was demonstrated that the optimum configuration of a flow system depends on the properties of polymer reagent solutions, their viscosity, and the different effects of clath-rate formation with iodine. It was found that the reaction somewhat accelerated in the presence of iodide ions, and amylose as a reagent exhibited the best properties, when the calibration function was described by a linear regression equation. The throughput capacity of this technique was as high as 220 or 140 samples per hour with the use of amylose or amylopectin, respectively. The technique is suitable for the direct determination of elemental iodine in seawater and salt. The detection limit of iodine with amylose was as low as 40 ng/mL.