Sequential injection renewable separation column instrument for automated sorbent extraction separations of radionuclides

A novel approach to the automation of sorbent extraction separations is described. An advanced sequential injection renewable separation column (SI-RSC) instrument was designed and optimized for automatically packing a separation column on-line, using it for a separation, and then disposing of the used separation material. Column packing/separation material disposal steps are accomplished fluidically using a frit restriction. Using a 250-mu L renewable column, procedures were developed for the separation and analysis of Sr-90, Am-241, and Tc-99 in aged nuclear waste samples employing Sr-resin, TRU-resin, and TEVA-resin sorbent extraction materials (Eichrom Industries), The separation performance of the RSC was identical to that of a freshly packed conventional column of similar size. With a renewable column, it is not necessary to elute all species from the column, carryover on the column from one separation to the next is eliminated, the same instrument can be used for multiple separations requiring different sorbent extraction media without physical changes to the instrument (sorbent extraction medium is selected in software), and the sorbent extraction material can be recovered for analysis of noneluted species.