Linear Starch Reagents: Cadmium Iodide—Linear Starch Reagent

Abstract

The cadmium iodide-linear starch reagent had been reported in two previous papers by the author and coworkers, but no extensive study made of the reagent itself. This work was primarily intended to study the reagent more thoroughly and to point out its usefulness and potentialities for the colorimetric determination of trace amounts of oxidizing substances. The intensity of the starch-iodide blue color developed in solution was found to be directly proportional to the concentration of the oxidizing agent over relatively wide ranges. Rate of color development was studied and the extinction coefficient determined. The reagent is colorless, unaffected by age, and capable of giving highly reproducible results. This reagent makes possible the first satisfactory utilization of the extremely delicate starch-iodine reaction for colorimetric work, and has the added convenience of stability. It should make possible the development of a number of new analytical procedures. © 1951, American Chemical Society. All rights reserved.