DETERMINATION OF SILVER-IODIDE BY HIGH-PRESSURE ION CHROMATOGRAPHY INSOIL AND WATER MATRICES AFTER SOLID-PHASE EXTRACTION

Silver iodide is determined in soil and water samples after reduction by zinc, in acidic with acetic acid environment at 60 degrees C, for 2 h. Iodide ions are subsequently determined by High Pressure Ion Chrom atography using a low capacity, PRP-X100 Hamilton 150 x 4.1mm, 10 mu m , anion exchange column filled with spherical poly(styrene-divinylbenz ene)trimethylammonium exchanger, with a mobile phase consisted of CH3O H-NaCl 0.1 M (55:45 v/v). Identification of iodide ions was achieved b y UV detection and quantitation was performed at 230 nm. Nitrate ions we:re used as internal standard at a concentration of 1.5 ng/mu L. Lim it of detection (S/N=3) was 0.8 ng for iodide ions. Recovery of iodide from silver salt was 95% with a reproducibility better than 6% RSD. R ecovery of silver iodide from spiked soil matrices was 90%. Solid phas e extraction, using SAX Lichrolut Merck cartridges, revealed recoverie s of iodide ions ranging from 86-108%. Iodides were eluted from sorben t using a mixture of 70-30 % v/v 0.1M NaCl-CH3OH as eluent. Statistica l evaluation of presented method was examined performing intra-day (n= 8) and inter-day (n=8) calibration studies and was found to be satisfa ctory with high accuracy and precision results.