SOLID-PHASE EXTRACTION FOR REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF IODIDE-ION

This paper describes the anion-exchange solid-phase extraction of iodi de ion (I-) using a column (Bond Elut(R) NH2) packed with aminopropyls ilyl bonded silica. The quantitative retention of I- on the solid phas e in the free (-NH2) form is obtained when the pH of the sample is adj usted below 5.0, while on the solid-phase in the acetate form it is ob tained below 6.7. The I- retained on the solid phase is effectively el uted with ammonia water. To eliminate the analytical interference from ammonium ion, I- eluted from the solid phase is passed through a cati on-exchange column packed with AG(R) 50W-X8, and is then subjected to reversed-phase HPLC with a UV detector. In the optimum extraction proc edures, the recoveries of I- from 1, 0.1 and 0.01 mM I- standard solut ions (0.5 mi) were 98.3 +/- 1.8, 92.9 +/- 2.0 and 88.0 +/- 3.5 %, resp ectively.