614 JOURNAL OF ANALYTICAL CHEMISTRY Vol. 58 No. 7 2003 THE INTERNATIONAL SYMPOSIUM Optimal conditions were determined for the sorp- tion of aluminum, iron, and zinc in the batch and dynamic modes. The results demonstrated that cellulose acetate mod- ified with R1 completely adsorbs (at pH 6) 9 mg of iron and 7 mg of aluminum per 1 g of the air-dry ion exchanger, and the sorbent with R2 adsorbs 8 mg of aluminum. Under these conditions, zinc in not adsorbed on either the first or the second sorbents. As follows from the results of this study, modified sorbents resulting on the basis of cellulose acetate can be used for the preconcentration and extraction of alu- minum and iron or aluminum and zinc. Preconcentration of Organic Compounds on Foamed Polyurethanes: Regularities and Examples of Analytical Application S. G. Dmitrienko, L. N. Pyatkova, O. M. Medvedeva, and Yu. A. Zolotov Department of Chemistry, Moscow State University, Vorob’evy gory, Moscow, 119899 Russia Foamed polyurethanes are of significant interest for the analytical chemistry of organic compounds. The specific features of these adsorbents are a high effi- ciency, versatility, chemical and mechanical stability, resistance to organic solvents, relatively low cost, and availability. To a large extent, the unique sorption prop- erties of these synthetic polymer materials are caused by the combination of various hydrophilic and hydro- phobic active centers and the reactive terminal groups. Sorption on foamed polyurethanes was studied for organic compounds of different classes: polycyclic aro- matic hydrocarbons, cationic and anionic surfactants, phenols, hydroxybenzoic acids and their azo deriva- tives, and sulfophthalein and xanthene dyes. We revealed the main factors affecting sorption and rela- tionships between the sorption parameters and physic- ochemical properties of the adsorbent and the adsorbed component. We proposed a classification of sorption systems involving foamed polyurethanes, which is based on the notion of different types of adsorbent– adsorbate intermolecular interactions. We developed sorption techniques for the precon- centration of polycyclic aromatic hydrocarbons, phe- nols, hydroxybenzoic acids, and ionogenic surfactants, which formed the basis of hybrid and combined analyt- ical procedures. It was demonstrated that the reason- able selection of the volume of the test sample and the mass of the adsorbent and the use of the consecutive sorption technique provide concentration coefficients up to n ¥ 104. We proposed new sorption–spectrometric methods of analysis based on the combination of the sorption preconcentration of compounds on foamed polyurethane and their determination directly in the adsorbent matrix using diffuse reflectance or lumines- cence spectrometry. ACKNOWLEDGMENTS The work was supported by the Russian Foundation for Basic Research, project no. 01-03-33102. Sorptive Extraction of Gold(III) with Silica Gels Chemically Modified with Mercapto, Amino, and Disulfide Groups V. N. Losev*, E. V. Buiko*, E. V. Elsuf’ev*, A. K. Trofimchuk**, E. B. Andrianova**, and A. V. Legenchuk** * Research Engineering Center Kristall, Svobodnyi pr. 79, Krasnoyarsk, 660041 Russia ** Shevchenko National University, Vladimirskaya ul. 64, Kiev, 01033 Ukraine We synthesized the following sorbents: silica gels chemically modified with mercapto and disulfide groups and silica gels with mercaptopropyl and amino- propyl groups simultaneously bonded to their surface at different SH : NH 2 molar ratios. For all sorbents containing mercapto groups, the recovery of gold(III) is 99.5–99.9% in a wide acidity range (4 M HCl–pH 8), and the sorption equilibration time is no longer than 2–3 min. For sorbents containing only primary amino groups, the recovery decreases from 96% at pH 4 to 10% at 2 M HCl. Upon the UV irradiation of wet adsorbates obtained by the sorption of gold(III) on silica gel containing only mercapto groups, intense yellow–orange luminescence (λ max =