RADIOMETRIC DETERMINATION OF BORON WITH MANDELIC-ACID AND ZINC-65-LABELED BIS(1,10-PHENANTHROLINE)ZINC(II)

The use of solvent extraction methods for the radiometric determinatio n of boron is scarce. This work was undertaken to examine the feasibil ity of an indirect radiometric method for the determination of trace a mounts of boron by solvent extraction. Mandelic acid was used as the c omplexing agent for boron and the complex anion formed was extracted a s an ion associate with zinc-65-labelled bis(1,10-phenanthroline)zinc( II) into isobutyl methyl ketone. The activity of zinc in the organic l ayer was measured using an NaI-Tl well-type scintillation detector, an d was a linear function of the concentration of boron in the aqueous p hase over the range 0-10 mu g in a final volume of 15 ml. A detection limit of 0.25 mu g of boron in a 15 ml aqueous volume could be achieve d. The interfering effect of various ions was overcome by selective di stillation of boron as methyl berate. The method was applied to the de termination of boron in Cr-Mo-B alloy, ointments, talcum powder and ey e lotion samples. The reliability of the proposed method was checked b y comparing the results obtained for the above samples with those give n by ICP-AES.