AMMONIUM PYRROLIDINEDITHIO-CARBAMATE-METHYL ISOBUTYL KETONE-GRAPHITE FURNACE ATOMIC-ABSORPTION SYSTEM FOR SOME TRACE-METALS IN DRINKING-WATER

A critical study of the solution conditions and other parameters affecting the reliability of the ammonium pyrrolidinedithiocarbamate-methyl isobutyl ketone (APDC-MIBK) extraction system for Ag, Cd, Co, Cr, Cu, Fe, Mn, Ni, and Pb was made. The following parameters were investigated in detail: pH of the aqueous phase prior to extraction, amount of APDC added to the solution following pH adjustment, the length of time needed for complete extraction and the time-stability of the chelate in the organic phase. Except for Ag and Cr which were quantitatively extracted only in a very narrow pH range (1.0-2.0 and 1.8-3.0, respectively), and Cd and Pb which were stable in the extracted MIBK phase only for 2–3 hrs, the solution conditions for quantitative extraction were not critical for the other metals. Simultaneous extraction of all the metals except Cd and Pb was also investigated. Good recoveries (100±10%) were obtained for a number of spiked raw, treated and distributed drinking water samples covering a wide range of hardness. It is concluded that the APDC-MIBK-GFAA procedure is reliable and precise under proper solution conditions. The method is now routinely used in our laboratory for the determination of a number of the above metals in various Canadian drinking water supplies. © 1979, Taylor & Francis Group, LLC. All rights reserved.