DETERMINATION OF CALCIUM, STRONTIUM, BARIUM AND YTTRIUM BY SPECTROPOLARIMETRIC ANALYSIS

A spectropolarimetric method of analysis was developed for calcium(II), strontium(II), barium(II) and yttrium(III) utilizing the stereospecific ligand, D-(-)-1,2-propylenediaminetetraacetic acid (D(-)PDTA). The optical rotation of the solution was monitored with a photoelectric polarimeter to determine the end point of the titration. The metal complexes and titrant are optically active and serve as self-indicators. Since D(-)PDTA is stereospecific in its reaction with these metals, maximum utilization of the optical rotation of these complexes is achieved. The observed optical rotation is linear with respect to concentration of the metal complexes; consequently, it is possible to perform straight line extrapolations to the end point. The effects of some parameters were investigated and optimum conditions were established. The range of the average deviations from visual chelometry for the four metals determined was 0.00 to 0.50%. © 1969, Taylor & Francis Group, LLC. All rights reserved.