SIMULTANEOUS DETERMINATION OF PHOSPHORUS AND SILICON BY NORMAL-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Separation of molybdophosphoric and molybdosilicic heteropoly acids ob tained under analytical conditions as ion associates with trioctylamin e by normal-phase HPLC on a column packed with Diasorb-130 CN with det ection at 320 nm was examined. A tetrahydrofuran-chloroform mixture (5 5 : 45) containing 0.1 mass % trioctylamine was used as the eluant. A procedure for the simultaneous determination of phosphorus and silicon without preseparation was developed. The detection limits are 0.06 mu g/mL in an initial solution (3 ng of an element in a 10-mu L sample o f a chloroform extract). After masking with fluoride, 1000-fold amount s of Ni(II), Co(II), Cr(III), and AI(III) and a 20-fold amount of Fe(I II) caused no interference. The separation time was 6 min, and the dur ation of a single determination was 20 min, taking into account the st age of sample preparation. The procedure was applied to the analysis o f tap water, spent nickel catalysts, and wastes containing organophosp horus compounds.